Check the construction of complete dentures. Laboratory stages of complete dentures production . Filing of complete dentures. Adaptation to the dentures. Processing of complete dentures after polymerization plastics. Correction of complete dentures. Repair of dentures. Effect dentures on oral tissues.
Dentures, also known as false teeth, are prosthetic devices constructed to replace missing teeth, and which are supported by surrounding soft and hard tissues of the oral cavity. Conventional dentures are removable, however there are many different denture designs, some which rely on bonding or clasping onto teeth or dental implants. There are two main categories of dentures, depending on whether they are used to replace missing teeth on the mandibular arch or the maxillary arch.
Dentures can help patients through:
- Mastication as chewing ability is improved by replacing edentulous areas with denture teeth.
- Aesthetics because the presence of teeth provide a natural facial appearance, and wearing a denture to replace missing teeth provides support for the lips and cheeks and corrects the collapsed appearance that occurs after losing teeth.
- the improvement of pronunciation of those words containing sibilants or fricatives by replacing missing teeth, especially the anteriors enabling patients to speak better.
- improving self-esteem
Modern dentures are most often fabricated in a commercial dental laboratory using a combination of a tissue shaded powder polymethylmethacrylate acrylic (PMMA) for the tissue shaded aspect, and commercially produced acrylic teeth available in hundreds of shapes and tooth colors.
The process of fabricating a denture usually begins with a dental impression of the maxilla or mandible. This impression is used to create a stone model that represents the arch. A wax rim is fabricated to assist the dentist or denturist with establishing the vertical dimension of occlusion. After this a bite registration is created to marry the position of one arch to the other.
Once the relative position of each arch to the other is known, the wax rim can be used as a base to place the selected denture teeth in correct position. This arrangement of teeth is tried in the mouth so that adjustments can be made to the Occlusion. After the occlusion has been verified by the dentist with the patient, and all phonetic requirements are met, the denture is processed.
Processing a denture is usually performed in a lost-wax process whereby the form of the final denture, including the acrylic denture teeth, is invested in stone. This investment is then heated, and the wax is removed through a sprue when it melts. The remaining cavity is then either filled by forced injection or pouring of the uncured denture acrylic. After a curing period, the stone investment is removed, the acrylic is polished, and the denture is complete.
Whether some or all of the natural teeth are missing, there are several benefits from replacing them with complete or partial dentures. Replacing missing teeth helps to fill out the smile by giving support to the cheeks and lips. Also, a more youthful, vibrant appearance is achieved by supporting facial muscles. Speaking, chewing, swallowing and smiling are also improved. Partial dentures prevent teeth from shifting into the spaces created by the missing teeth. This helps prevent bite problems and decreases the likelihood of gum disease that is often associated with crooked teeth.
When a denture is attached to dental implants, especially the lower denture, its retention and stability are dramatically improved. Also, the bone loss that occurs yearly with complete dentures is avoided.
Stages of making complete removable dentures
Clinical stages
First visit
obtaining anatomical impressions (alginate material is usually used for making impressions ). Similar impressions are taken at partial defects of dentition
Second visit:
Obtaining functional impression (with thermoplastic or silicone mass). Is obtained by special samples
Third visit:
Determination of the central relationship of the jaws, the choice of form and color of teeth, prosthetic plane determination, drawing landmarks for setting the teeth
Fourth visit:
Check of prosthesis structures in the mouth
Fifth visit:
Fitting the prosthesis to the patient jaw and its correction
Facebow Record
Relates Maxilla to Transverse Hinge Axis
Determine Occlusal Vertical Dimension
Facial Height/Separation of Dentures
Centric Relation Registration
Ant/Post & Mediolateral Relationships
Laboratory stages
1. Getting a model from plaster, defining the boundaries of the denture base and making an individual spoon
2. Production of a model(better use highly strong varieties of gypsum). Manufacture of wax patterns with bite rollers
3. Strengthening plaster models in an occludor or articulator, torus and exostosis isolation, setting artificial teeth in wax basis
4. Final modeling of a denture base, denture plastering in a flask, replacing wax on plastics, polymerization, grinding and polishing the prosthesis
5. The final polishing of prosthesis
Box Impression
Stronger cast with peripheries for Processing
Delivery of complete removable denture is a final stage of production of complete removable dentures.This is fixation, correction, adaptation processes and recommendations on the use of the denture. The main condition for the denture holding on toothless jaw is anatomical retention, functional suction – physical and biological methods for fixing dentures on toothless jaws. So making a functionally complete removable denture depends largely on correctly obtained functional impression, reasonable choice of impression mass , methods of edge design of functional impression , wringing or unloading mucous membrane, prosthetic bed, etc.
Removable dentures are foreign body for a mouth and the patient, in addition, it inadequately conveys chewing load. So study the process of adjusting to it is very important.
Fixing complete romovable denture in the mouth is a responsible clinical moment. The procedure of entering complete romovable denture does not require any special efforts from a dentist- orthopaedist, but the next steps related to this, require special attention and patience.
The procedure of fixing finished complete romovable denture begins with a detailed review of them. Reviewing dentures is begun with detecting visible to the eye and those inequalities that are defined palpatorily, and are immediately removed by a grinding method . After entering the prosthesis in the oral cavity it is checked whether the base does not fall from the prosthetic bed tissue and there are no balancing, and only then it is offered to the patient to close the teeth in position of the central relationship. Stability of dentures in upper jaw is checked by alternate manual finger pressing on the front and side teeth. The strength of locking valve in the field of soft palate is checked by folding back the cutting edges of upper teeth in lateral direction, on the lower jaw in the same way you assign the degree of base fixation in distal spots , in turns onthe right and left.
In addition, prosthesis fixation is checked by a patient himself, who performs set of movements of the mandible, mimic muscles and tongue. Basis of the prosthesis does not move from prosthetic bed during normal muscle contractions. While fixing the complete romovable denture lowering can be seen or increase of intercollar height, fixing the central relationship of the jaws in lateral occlusion, but often mistakes are made in case of fixation of the central relationship of the jaws, when the patient pulls the lower jaw in front occlusion. In the absence of closure in the region of the frontal or side teeth such dentures need to be remade. Defined preliminary teeth contacts, areas of increased pressure within the denture base, and areas where muscles are excessively overlapping prosthesis, are removed by grinding-off. While fixing the prosthesis side and front-rear movements must be checked, artificial teeth, at which the bite increases, particularly the canines must be grinded-off. Different actions are taken to keep maximum contact between the artificial teeth during movements. Front teeth, if they overlap considerably lower ones, are subjected to shortening.
Dentist-orsthopaedist after the above described manipulations should give the patient recommendations concerning the use of prostheses in the early days. Especially it should be done if the patient’s complete romovable dentures are made for the first time. Therefore it is necessary to emphasize that the prosthesis is a foreign body in oral cavity and it must be accepted this way. Often, after fixing the prosthesis a patient has a headache, nausea etc. In this case, it is recommended to withdraw dentures from the mouth. An important consideration during the use of prostheses is the first day. The patient is asked, if possible, during the first period not to remove the dentures from the mouth even at night. Of course the doctor very easily achieves a proper fit of the denture base to prosthetic bed tissue, easy input and output from his mouth, but over time the patient comes to the doctor complaining that the prosthesis causes pain in certain areas where they have contact with mucous membrane.
The elimination process places on the basis of the denture, which injures prosthetic bed tissue , is called a correction. Correction is conducted usually starting from the very next day after fixing dentures. The patient is asked to not use them in case of a pain, but about for 2-4 hours before visiting the doctor to enter the dentures in the mouth. Doctor during the review of oral mucous membrane easily determines the place of injury prosthetic bed tissue by edge of denture base. Denture places, which cause injury, are grinded-off and polished.
The number of corrections is different and can vary from one to ten. In the first period of prostheses use the patient must be supported psychologically, noting that he already speaks the words that it becomes easier to eat ,that after a while all the discomfort disappears. The described aspects of getting used to complete removable denture are called “adaptation””.
The term “adaptation” means adjustment, fitting. In terms of physiology orthopedic treatment of complete romovable dentures is a very serious interference in the human body and for the doctor to underestimate its complexity is unacceptable.
Complex mechanisms of adaptation can be better understood if refer to classic works of I.P. Pavlov of braking process.
Complete romovable dentures are unusual stimulus, the patient experiences it as a foreign body. Patients often are obsessed with feelings of prosthesis and its location in the oral cavity, which prevents them from performing the work and fully relax.
In the first stage together with all the listed deficiencies salivation increases, indicating the first phase of adaptation, which is called reflex irritation, and goes from 1 to 3 days. The nature of this reflex is unconditional, it recalls the reaction caused by the action of substances which are not accepted by the body. Vomiting reflex is caused by mechanical stimulation of receptor root of the tongue or soft palate. This reflex has a protective character. During the first week using the prosthesis the mentioned reaction to the irritation begins to subside, foreign body sensation changes. Salivation decreases, vomiting reflex disappears. These signs indicate that second phase of adaptation starts, entitled conditioned inhibition and extended for one further week.Patient ceases to feel the presence of the denture in the mouth, forgets about it and feels uncomfortable only when the prosthesis should be removed from the mouth. The third phase of adaptation extends to 30-35 days and is called extinction of conditioned stimuli and habituation to complete romovable denture. Valuable criterion for assessing adaptation to complete romovable dentures is adaptation.
E.I. Gavrilov (1978) believes that doctors should monitor patients for as long as there is no sure of the full adaptation to the onset of complete romovable denture. These measures, he calls the principle of completeness of treatment.
Often, doctors are asked the following question: whether to remove a prosthesis from oral cavity at night? If this question is not of only one person, then, in principle, dentures need to be removed from the mouth to decrease its staying on its mucosa. It is more difficult to solve this issue in relation to a particular patient. Before giving advice, the doctor must take into account the patient age, sex, marital status, as far as changing the aesthetic appearance of the patient in case of removing a prosthesis from an oral cavity. Especially it concerns younger patients, older patients in recommendations for removing a prosthesis from an oral cavity at night does not cause psychological stress.
Patients are recommended to rinse their mouth with decoction of oak bark, weak Nitrofural solution (1:5 000), solution of potassium permanganate. Do not use baking soda because it leads to breaking mucosa, which in turn will facilitate the emergence of prosthetic stomatitis.
Patient instruction in the care of the dentures should include the following topics:
- Denture insertion and removal
- Cleaning dentures
- Diet
- Night use
- Recall
- Use of denture adhesive
Denture Insertion
Denture insertion is seldom a topic requiring patient instruction at the insertion appointment. However, there are three possible exceptions to this rule:
- First-time denture wearers may want to know if it matters which prosthesis is inserted first. A patient asking about this should be reassured that the order of insertion does not matter—unless there is virtually no retention to the upper denture. In this case the lower plate should be inserted first.
- If the patient has significant undercuts in the retromylohyoid space, instruction should clarify the mandibular denture needs to be positioned posterior to its ultimate position; the posterior segment seated; and then the prosthesis brought anteriorly and then fully seated.
- If the patient suffers from cognitive dysfunction due to stroke or Alzheimer’s Disease (or other dementia), it may be impossible for him or her to initially distinguish upper and lower denture or to correctly position a prosthesis over the ridge. In such an event, the dentist needs to work with both the patient and the caregiver who will be able to reinforce the information away from the office. Parenthetically, it should be stressed that for some patients, use of a mirror will actually make the process MORE difficult, whereas it may ease matters for others.
A fourth situation meriting instruction on insertion occurs when the subject of denture adhesive is brought up, whether by the patient or the dentist. This will be covered in more detail shortly, in the section titled “Protocol for the Use of Denture Adhesive.”
Denture Removal
Patients with no prior familiarity to removing a denture should be instructed to break the seal by running one or both fingers along the full length of the flanges, or by puffing out the cheeks (making a “P!” sound).
Cleaning Dentures
Patients should be taught to remove their prostheses after each meal for a rinsing and to clean thoroughly at least once daily. Thorough cleaning involves brushing and soaking.
Brushes specifically designed for denture cleaning should be recommended. These feature a wide handle for easy gripping; stiff bristles of one length on one side of the head (for use against broader, flatter denture surfaces such as facial, palatal, and lingual surfaces); and bristles set in a pyramidal arrangement on the other side (for cleaning the tissue surface of the denture). Patients should be cautioned not to use toothpaste (other than toothpaste specifically designed for use on dentures) as the high abrasivity of non-denture toothpaste will scratch acrylic, thereby, dulling and removing anatomic and esthetic details from the denture surface.
Daily soaking in cleanser specifically designed for dentures is recommended for assuring cleanliness and eliminating odors. Patients should be cautioned to always rinse the denture thoroughly after soaking in order to avoid ingesting traces of caustic cleaning agents.
Diet
Patients should be cautioned that chewing and swallowing with the new dentures is a learned behavior and lip- and tongue-biting are very common risks at first. To ensure comfortable eating while fostering confidence in the prostheses, patients should be urged to continue to consume the quality and variety of foods they did prior to receiving the new dentures until those foods can be easily consumed without discomfort from the dentures. As a patient gains skill with the prostheses, the range of foods can gradually expanded to include crisp fruits cut in small pieces, nuts, and sandwiches.
- Continue former diet
- Add new foods as comfort increase
Night Use
Patients, whether first-time users or those receiving a new set, should always be instructed to leave their dentures out of the mouth for at least 6 hours per day in order to allow the bearing tissues to rest. For most individuals, this is most conveniently and acceptably accomplished during sleep. Whenever dentures are removed for an hour or more, they should be thoroughly cleaned and then placed in water or a cleansing agent.
Recall
Patients with complete dentures likely have lower awareness of preventive dental behaviors than the average American consumer. As such, a deliberate, proactive effort must be made to bring them back to the practice annually for a recall. This is important to re-evaluate and revise, as necessary, the prostheses and to assess the health of the oral cavity. Over 90% of the 30,000 new cases of oral cancer diagnosed in America annually are found in persons over age 50 years. Denture use is correlated with advanced age, use of tobacco, and lower socioeconomic status—the three strongest risk factors for development of oral cancer. As such, it is essential for dental professionals to establish and stress a program of recall examinations for their edentulous patients just as they do for their patients who maintain their natural teeth.
The main condition for the maintenance of dentures on toothless jaw is their anatomical retention, functional suction – physical and biological method of fixation of prostheses on toothless jaws. So making a functionally complete dentures depends largely on obtaining functional impression correctly,reasonable choice of impression mass, methods of designing edges of a functional impression, streak or unloading mucosal prosthetic bed, etc.
Removable dentures are foreign body for the mouth and the patient, it also conveys inadequate chewing load. So study the process of adjusting to it is very important..
Processing of complete dentures.
After completion of plastics polymerization and complete flask coolness its release of her dental pliers begins. Denture is taken out from the flask very carefully. First, take the lid and the bottom of the flask and pull entire unit with the pressing, and then gently release prosthesis of gypsum.Exemption from plaster denture does not cause the difficulties, if good insulation of plaster model surface was done .
Eliminating inequalities, surface dissonances , residues of plastic on the surface basis is carried with various instruments – files,burins, abrasives, drills, burs. Edges of the prosthesis are formed in curves, keeping the thickness and boundaries. Particular attention is given to treatment of artificial teeth in their places of attachment to an artificial basis.
During prosthesis processing with grinding wheel and another it is necessary to continually moisten the surface, which is treated to prevent overheating and deformation of plastic.
Denture surface facing the oral mucous membrane, is treated very carefully, cutting off only visible remnants of plastic so as not to disrupt relief which must correspond to microrelief of mucosal prosthetic bed.
For polishing the denture base sandpaper is used with different grain size, which is firmly fixed in drill paperhold. grinding is started with rough grinding paper and finished with fine, getting their smooth surface.
Polishing is begun with the application of tapered felted folds , applying pumice mixed with water on the denture surface. After appearing smooth surface folds are replaced with rigid brush that allows to polish places difficult of access. For providing mirror shine on a surface a soft brush from threads and chalk mixed with water or mineral oil is used. The surface of the prosthesis, facing to the mucosa, and artificial teeth are polished with soft brushes with little effort, to prevent abrasion of plastic and violations of relief form.
Denture repair.
Denture bases repair is necessary if:
1)basis cracks or complete fracture ,
2) partial or full fracture of an artificial tooth,
3) clamp failure ,
4) removal of an abutment tooth,
5) replacing the removed artificial tooth with an artificial one.
Depending on the nature of the damage repair may be done by obtaining an impression with or without prosthesis. In the case when there is a crack or full fracture of the base and when it is not possible to make the prosthesis and stick together, do not get an impression. But if denture parts caot be composed or there is lack of some of them an impression must be obtained along with prosthesis parts . In the laboratory, after casting models or, as is said, “pouring”, the prosthesis parts are removed, their edges are grinded off, removing plastic from each end 2-3 mm ; grinding off is conducted with dental mills. On the boundary of the fracture surface is polished with files, burins and mills , giving roughness. Fragments are put on the model, the gap between the parts of the prosthesis is filled with wax and basis simulation is conducted.
After the simulation model is plastered by direct method in flask basis, the entire prosthesis is filled with liquid plaster, leaving open only part of the wax. having cast a contraform after crystallization of gypsum flask is opened and wax is smelted with hot water. After cooling flask plastic preparation is made. For one correction on average 4.3 g polymer and 2 ml of monomer are needed. Before forming the plastic dough break lines are wiped with a monomer, the required number of plastic dough is imposed , covering its wet with cellophane, and pressing is done. After the control cellophane is removed, plastic residues are removed , if necessary,plastic dough is added and final pressing is done. Having checked the flask fixation on a clasp it is dipped into the bowl with water and polymerization is done. After treating and polishing denture again isfixed in the mouth.
In the case when there is breakage or fracture of artificial teeth or clamps, when there is a need for clamps transfer to another place because of loss of abutment teeth the denture fining is done. Its essence is that an impression is obtained from the jaw with prosthesis put on it , and then model is cast.The position of central occlusion is fixed with thwe help of blocks from the warm wax. Model is plastered in occludor. The clamp full bending is done , and if necessary setting an artificial tooth is conducted. Model is plastered in a flask and wax is replaced on plastic by conventional methods.After the prosthesis is treated, polished, grinded and sent to a clinic for fitting and fixing.
Separately we will stiop at denture bases fining with selfhardening plastics. This method is widely used in clinical prosthodontics, but necessary to recall that the conditions of its application is to conduct polymerization in the apparatus under pressure to reduce residual monomer.
Description of fining is to glue parts with dichlorineethan denture glue, which is contained in complex of selfhardening plastics ‘Protacryl’ and ‘Redont’.
Parts of the prosthesis are placed along the fracture line, having glued them before and are kept in this position for 2-4 min.
On cemented prosthesis plaster model (‘pidlytok’) is cast. having smeared prosthesis and plaster with vaseline , a contramodel is obtained with the new portion of densely mixed plaster. After, the prosthesis is removed from the model and broked through bonding line, the fracture is grinded each side for 1-2 mm, making the notch.
Model and contramodel are smeared with insulating varnish ‘Izokol’, then part of the prosthesis is placed on the model.
Plastic dough is prepared with selfhardening plastic, strewing powder in monomer tu full, covering wuth glass pot on top to prevent weathering monomer.
The process of maturation of plastic dough goes 3-5 minutes, depending on air temperature. Fracture line is greased with monomer. Polymerization should be in a special apparatus under pressure for 8-10 minutes. After machining, grinding and polishing dentures are passed on for fitting and fixing in the mouth
Complete removable dentures correction.
The places elimination process on the basis of denture, which injure prosthetic bed tissue, is called a correction. Correction is conducted usually starting from the very next day after fixing dentures. The patient is asked to not use them in case of a pain, but about for 2-4 hours to visit the doctor must enter the dentures in the mouth.
Doctor during the review of oral mucous membrane easily determines the place of injury tissue prosthetic bed with edge ofdenture base . Places of denture, which cause injury, must be grinded off and polished.
The number of corrections is different and can vary from one to ten.
In the first period of prostheses for each visit the patient must be supported psychologically, noting that he already speaks the words that it becomes easier to eat that after a while all the discomfort disappear.
Denture stomatitis is a common oral mucosal lesion in the United States and Western Europe. Prevalence rates of 2.5-18.3% in adults aged 35-44 years or 65-74 years are reported, with a predominance in the latter age group.Although patient age and denture quality alone do not predispose individuals this mucosal condition, the odds of developing stomatitis, denture-related hyperplasia, and angular cheilitis are increased almost 3-fold in denture wearers. Studies indicate that correlations may exist with the amount of tissue coverage by a maxillary denture, vitamin A levels, smoking of cigarettes, and not removing dentures.
It may be that you have very few symptoms at all but there are some things to watch out for. When you take your dentures out, the area underneath may be very red. It could be painful when you are putting your dentures in or taking them out. You may also find you have red sores at the corners of your lips or on the roof of your mouth. White patches can appear anywhere on the inside of your mouth. You will most likely have bad breath and your dentures will feel that they are irritating the skin more thaormal.
If you suspect you have denture stomatitis, visit your dentist. He will be able to recognize the symptoms and prescribe a suitable course of treatment. If it goes untreated, your mouth will become very sore and it can ultimately lead to poorly fitting dentures in the near future. It can also last for years if you do not notice it and get some treatment.
Pathophysiology
Mucosal factors have been implicated in the etiology of this condition, as have behavioral and manner-of-use factors in patients who wear complete dentures. In these patients, the nighttime wear of the prosthetic appliance is the most significant factor.
Although the dominant etiologic factor now appears to be fungal infection, other factors must be considered; these include the prosthetic device itself and also local and systemic factors in patients who are aging and edentulous. The extent of inflammation has been correlated with the presence of yeast colonizing the denture surface. Trauma has been shown to have a role in the production of basement membrane alterations involving expression of type IV collagen and laminin (alpha 1), thus indicating a possible relationship between these elements and denture stomatitis. Regarding the prosthesis-related factor, an allergy in the form of contact mucositis is suggested. This reaction may be related to the presence of resin monomers, hydroquinone peroxide, dimethyl-p -toluidine, or methacrylate in the denture. Furthermore, contact sensitivities such as this one are more common with cold or autocured resins than with heat-cured denture-base materials.
Candida species have been identified in most patients or in all patients, with Candida albicans being the predominant species isolated in addition to many other candidal species. Whether the organism is merely commensal in this situation remains an issue because of the frequency of such organisms in the general population; the role of this organism as the sole etiologic factor in denture stomatitis is unclear; however, the presence of candidal organisms within the overall biofilm lends credence to its role in the development and maintenance of denture stomatitis. The etiology is best considered multifactorial, with the prosthesis considered the prime etiologic factor. The character of biofilm communities of denture wearers, however, has been shown to be distinctive when compared with healthy non – denture-wearing individuals.
Age
The disease is more common in elderly persons than in young persons because elderly persons are more likely to wear dentures and because their level of oral and denture hygiene is reduced. In addition, age-related chronic disease (eg, type 2 diabetes mellitus), iatrogenic drugs, and age-associated immunocompromise contribute to this risk level.
Denture stomatitis usually occurs in a patient who wears a complete maxillary denture or a partial denture. The presence of deteriorating temporary soft denture lining material and an improperly matched cleanser (which generally is the case) is associated with an increased presence of candidal organisms within the biofilm.
In almost all patients, the duration of the lesion is usually unknown because of its asymptomatic nature.
On rare occasions, patients may complain of slight bleeding and swelling in the involved area, as well as a burning sensation, a xerostomialike quality, or cacogeusia.
Although symptoms are uncommon, the clinical presentation of erythema and edema in the part of the palatal mucosa covered by the denture base is a diagnostic finding. Intense erythema is the most common finding. Note the image below.
A variably intense erythema distributed over the part of the mucosa covered by the denture base is diagnostic of denture stomatitis.
At times, an obvious fungal infection in the form of white surface colonies or plaques may be observed on the mucosal surface. Variably intense erythema, which may also be associated with scattered petechiae, is distributed over the mucosa covered by the base of the denture but not beyond. Palpation of the involved mucosa reveals no tenderness or tissue friability. The severity of denture stomatitis can vary (see Staging).
Risk Factors
- Poor oral hygiene
- Dietary deficiencies and malnutrition
- Chronic systemic disease
- Immune deficiencies
- Poor denture
- Smoking
- Cancer therapies
Diagnostic Tests and Interpretation
The diagnosis relies on clinical symptoms and history. Testing is not routinely performed.
Lab
- Tzanck test of historic interest only; herpes simplex virus (HSV) culture
- Serologic test for syphilis
- CBC; cultures to determine secondary infection
Follow-Up and Special Considerations If not resolving in 7–14 days or getting worse, consider CBC.
Diagnostic Procedures/Other
- Biopsy if persistent/recurrent/suspicious
- Immunofluorescence is useful in the differential diagnostic between RAS and bullous skin diseases
Pathological Findings Biopsy suspicious lesions or lesions that fail to heal or chronically recur to rule out oral or hematologic cancer or vasculitis.
Treatment
Treatment of stomatitis depends on the causative factors. If cause is allergic, identification removal of the agent is critical. For infectious causes, antibiotic or antifungal regiments. Steroidal anti-inflammatory drugs for systemic conditions with stomatitis manifestation. If the cause of stomatitis is due to medical treatment or cancer therapy, treatment needs to be more aggressive.
- Acetaminophen or ibuprofen for analgesia
- Steroids, colchicine, and cytotoxic drugs for Behçet disease
- 2% viscous lidocaine (Xylocaine) swish and spit for local discomfort
- Liquid diphenhydramine (Benadryl) by mouth or swish and spit, for allergic reactions
- Antibiotics for gangrenous stomatitis (penicillin and metronidazole are reasonable first-line agents; often start with IV)
- Antifungal ointment (e.g., nystatin [Mycostatin]) for candidiasis-complicating angular stomatitis
- For candidiasis: Nystatin oral suspension 400,000 units (4 mL) q.i.d. × 10 days; swish and swallow (1 mL q.i.d. for infants)
- Acyclovir 200–800 mg 5 times a day × 7–14 days for herpetic stomatitis
- Sucralfate (Carafate) suspension 1 tsp swish in mouth or place on ulcers q.i.d. (helpful)
- Topical 0.2% hyaluronic acid for recurrent aphthous ulcers
- “Miracle mouth rinses”: Various combinations of the preceding in equal parts; use swish and spit out q.i.d.:
- Maalox or Mylanta, diphenhydramine, lidocaine
- Maalox or Mylanta, diphenhydramine, Carafate
- Duke’s: Nystatin, diphenhydramine, hydrocortisone
- Chemical cauterization with silver nitrate for aphthous stomatitis (treatment can cause burning sensation)
- Contraindications: Allergy to specific medication
- Precautions: Toxic dose of topical lidocaine is uncertain, but likely only 25–33% of dose may have significant absorption from open ulcers or mucous membrane.
- Topical minocycline for aphthous stomatitis (4)
- Steroid oral rinses (see “General”) or topical preparations for aphthous ulcers (Kenalog in Orabase) or oral steroids injected into lesions for severe cases
- Thalidomide 20 mg 1–2× daily × 3–8 weeks in HIV-positive patients with nonhealing aphthous ulcers (extreme caution for birth defects)
- For prevention or reducing severity of mucositis with cancer treatments, these agents have some evidence of benefit: allopurinol, aloe vera, amifostine, cryotherapy, glutamine (IV), honey, keratinocyte growth factor, laser, and polymixin/tobramycin/amphotericin (PTA) antibiotic pastille/paste (5)
General Measures
- In most cases, treatment of symptoms only
- Severe cases may require parenteral fluids, particularly children.
- Good oral hygiene
- Topical anesthesia
- Analgesics
- Oral rinses such as half-strength hydrogen peroxide
- Smoking cessation
- Refit dentures; daytime wear only
- Avoid specific allergens.
- Replace vitamin deficiencies.
- Treat malnutrition if present.
Prognosis
- Herpetic: Self-limited, with resolution in 7–14 days
- Hand-foot-mouth disease: Same as for herpetic
- RAS: 7–14-day course per episode
- Vincent: May progress to fascial space infection with airway compromise or sepsis
- Nicotinic: Resolves with cessation of smoking
- Denture: Resolves with proper fitting, careful oral hygiene, and daytime-only denture wear
- Erythema multiforme: Resolution in 2–3 weeks
- Stevens-Johnson: Resolution in about 6 weeks with adequate supportive care
- Recurrent ulcerative: As the name implies, recurs over time, but the overall prognosis is good
- Recurrent scarifying: Occasional patients suffer continuous ulcers; others have recurrence with eventual scarring. The prognosis is otherwise good.
- Behçet disease may recur for several years. Overall prognosis is related to other aspects of the disease.
- Angular: After correction of mechanical problems, allergic disorders, and nutritional deficiencies, the prognosis is good.
- Gangrenous: The most serious stomatitis, requiring aggressive treatment with IV antibiotics and débridement to avoid death
- Scarlatina: The prognosis is related to other manifestations of the disease.
- Herpangina: 7–14-day course with total resolution
- Uremic: Depends on the underlying renal disease
- Recurrent scarifying stomatitis may result in intraoral scarring with restriction of oral mobility.
- Behçet disease may result in visual loss, pneumonia, colitis, vasculitis, large-artery aneurysms, thrombophlebitis, or encephalitis.
- Gangrenous stomatitis may lead to facial disfigurement and even death.
- Scarlet fever may result in cardiac disease.
- Herpetic stomatitis may be complicated by ocular or CNS involvement.
Processing of complete dentures.
After completion of plastics polymerization and complete flask coolness its release of her dental pliers begins. Denture is taken out from the flask very carefully. First, take the lid and the bottom of the flask and pull entire unit with the pressing, and then gently release prosthesis of gypsum.Exemption from plaster denture does not cause the difficulties, if good insulation of plaster model surface was done .
Eliminating inequalities, surface dissonances , residues of plastic on the surface basis is carried with various instruments – files,burins, abrasives, drills, burs. Edges of the prosthesis are formed in curves, keeping the thickness and boundaries. Particular attention is given to treatment of artificial teeth in their places of attachment to an artificial basis.
During prosthesis processing with grinding wheel and another it is necessary to continually moisten the surface, which is treated to prevent overheating and deformation of plastic.
Denture surface facing the oral mucous membrane, is treated very carefully, cutting off only visible remnants of plastic so as not to disrupt relief which must correspond to microrelief of mucosal prosthetic bed.
For polishing the denture base sandpaper is used with different grain size, which is firmly fixed in drill paperhold. grinding is started with rough grinding paper and finished with fine, getting their smooth surface.
Polishing is begun with the application of tapered felted folds , applying pumice mixed with water on the denture surface. After appearing smooth surface folds are replaced with rigid brush that allows to polish places difficult of access. For providing mirror shine on a surface a soft brush from threads and chalk mixed with water or mineral oil is used. The surface of the prosthesis, facing to the mucosa, and artificial teeth are polished with soft brushes with little effort, to prevent abrasion of plastic and violations of relief form.
Denture repair.
Denture bases repair is necessary if:
1)basis cracks or complete fracture ,
2) partial or full fracture of an artificial tooth,
3) clamp failure ,
4) removal of an abutment tooth,
5) replacing the removed artificial tooth with an artificial one.
Depending on the nature of the damage repair may be done by obtaining an impression with or without prosthesis. In the case when there is a crack or full fracture of the base and when it is not possible to make the prosthesis and stick together, do not get an impression. But if denture parts caot be composed or there is lack of some of them an impression must be obtained along with prosthesis parts . In the laboratory, after casting models or, as is said, “pouring”, the prosthesis parts are removed, their edges are grinded off, removing plastic from each end 2-3 mm ; grinding off is conducted with dental mills. On the boundary of the fracture surface is polished with files, burins and mills , giving roughness. Fragments are put on the model, the gap between the parts of the prosthesis is filled with wax and basis simulation is conducted.
After the simulation model is plastered by direct method in flask basis, the entire prosthesis is filled with liquid plaster, leaving open only part of the wax. having cast a contraform after crystallization of gypsum flask is opened and wax is smelted with hot water. After cooling flask plastic preparation is made. For one correction on average 4.3 g polymer and 2 ml of monomer are needed. Before forming the plastic dough break lines are wiped with a monomer, the required number of plastic dough is imposed , covering its wet with cellophane, and pressing is done. After the control cellophane is removed, plastic residues are removed , if necessary,plastic dough is added and final pressing is done. Having checked the flask fixation on a clasp it is dipped into the bowl with water and polymerization is done. After treating and polishing denture again isfixed in the mouth.
In the case when there is breakage or fracture of artificial teeth or clamps, when there is a need for clamps transfer to another place because of loss of abutment teeth the denture fining is done. Its essence is that an impression is obtained from the jaw with prosthesis put on it , and then model is cast.The position of central occlusion is fixed with thwe help of blocks from the warm wax. Model is plastered in occludor. The clamp full bending is done , and if necessary setting an artificial tooth is conducted. Model is plastered in a flask and wax is replaced on plastic by conventional methods.After the prosthesis is treated, polished, grinded and sent to a clinic for fitting and fixing.
Separately we will stiop at denture bases fining with selfhardening plastics. This method is widely used in clinical prosthodontics, but necessary to recall that the conditions of its application is to conduct polymerization in the apparatus under pressure to reduce residual monomer.
Description of fining is to glue parts with dichlorineethan denture glue, which is contained in complex of selfhardening plastics ‘Protacryl’ and ‘Redont’.
Parts of the prosthesis are placed along the fracture line, having glued them before and are kept in this position for 2-4 min.
On cemented prosthesis plaster model (‘pidlytok’) is cast. having smeared prosthesis and plaster with vaseline , a contramodel is obtained with the new portion of densely mixed plaster. After, the prosthesis is removed from the model and broked through bonding line, the fracture is grinded each side for 1-2 mm, making the notch.
Model and contramodel are smeared with insulating varnish ‘Izokol’, then part of the prosthesis is placed on the model.
Plastic dough is prepared with selfhardening plastic, strewing powder in monomer tu full, covering wuth glass pot on top to prevent weathering monomer.
The process of maturation of plastic dough goes 3-5 minutes, depending on air temperature. Fracture line is greased with monomer. Polymerization should be in a special apparatus under pressure for 8-10 minutes. After machining, grinding and polishing dentures are passed on for fitting and fixing in the mouth
Complete removable dentures correction.
The places elimination process on the basis of denture, which injure prosthetic bed tissue, is called a correction. Correction is conducted usually starting from the very next day after fixing dentures. The patient is asked to not use them in case of a pain, but about for 2-4 hours to visit the doctor must enter the dentures in the mouth.
Doctor during the review of oral mucous membrane easily determines the place of injury tissue prosthetic bed with edge ofdenture base . Places of denture, which cause injury, must be grinded off and polished.
The number of corrections is different and can vary from one to ten.
In the first period of prostheses for each visit the patient must be supported psychologically, noting that he already speaks the words that it becomes easier to eat that after a while all the discomfort disappear.
Model quality check
Attention is paid to their integrity: existence of splits, pores, cracks, signs of injury by technical spatula, blurriness of prosthetic bed lines or defects on its surface. If defects occur one should again take the functional impression and cast new models.
Setting teeth in articulator check:
Attention is paid to color, size, style of teeth, incisor overlap size . Numbers of color, size and style teeth should correspond to preliminary record in production warrant.
Lower incisors overlap by upper ones should be in the range 1-2 mm. The upper front teeth lie 2 / 3 outside the mid-alveolar crest, and 1 / 3 through its center. Lateral teeth should have fisur contact. All teeth must have two antagonists, except the first lower incisors and second molars in the maxilla.
Molars and premolars must be placed in the middle alveolar process adhering to interalveolar lines. Intensity of sagittal and transversal compensation occlusion curves are taken into account.
Existence of palatal contact and tongue bumps of chewing teeth from the inside are checked.
Attention is paid to modeling wax base, its edges extensionality,fit tightness to the model.
Wax structure of the future prosthesis in the mouth check:
Dentures are inserted into the mouth and the correct placement of the median line between the central incisor, which should coincide with the middle line of the face is controlled. When opening mouth slightly only cutting edges of incisors must be visible and at a smile front teeth are viewed almost to the neck. Type of tooth should correspond to the face shape. Patients are offered to perform the speech test, during which the distance between the front teeth, upper and lower jaws should be about 5 mm.
When checking the construction of dentures errors made in defining the relationship of the central jaw can be revealed. They can be divided into 5 groups:
1) incorrect determination of facial lower part height (lowering or increasing);
With increased bite facial expression of the patient will look somewhat surprised, nasolabial and cheek folds will be smoothed, while speech test “knock” can be heard, tooth gap in front during the speech test will be less than 5 mm, gap (2-3 mm) in a state of physiological rest will be missing . This error is eliminated by the following. If the upper dentition is set correctly, and increase was due to lower teeth, the teeth should be removed from the lower base wax, a new roller should be made or basis with a bite roller be taken, upon which the central relationship of the jaws was established, and the height is redetermined. If the setting of upper teeth done wrongly (incorrect prosthetic plane), then bite rollers for an upper jaw are made. Then again, the central relationship of jaws is defined and teeth are set. At height lowering of the facial bottom part, when the upper teeth are set correctly, a heated wax strip is imposed on the lower dentition and redefinition of the central relationshipn of the jaws is made, bringing the height to normal.A new wax base with an occlusion roller can be made for a lower jaw. If the reason of the height lowering are the upper teeth, it is necessary to redefine the central relationship of the jaws using new upper and lower rollers.
2) fixation of the mandible with a shift in the horizontal plane;
most common mistake in defining the central relationship of the jaws is the advancement of the lower jaw forward and fixing it in that position. During checking structure dentition prognathic relationship is found out , mainly bump closing of lateral teeth, gap between the front teeth, bite rise to a height of bumps. This error is eliminated by redefining the central relationship with a new occlusion platen in side of mandible, and a group of front teeth is left for control.
Displacement of the mandible backwards at determination of the central relationship of the jaws of possible with loose joints. When checking anterior relationship of dentition is detected, papulose closing of lateral teeth, bite raising on papulose height. Fault is eliminated, redefining jaw central relationship with a new bite roller on the lower jaw. However, it should be noted that this is not always possible, because often lower jaw isnotfixed in a certain position .Checking the design of denture at displacement of the mandible to the right or left, you may find bump closure on the opposite side of the shift, bite increase, a shift of the centre of lower denture in the opposite direction, gap between chewing teeth on the side of displacement. The error is possible to be corrected by redefining the jaw central relationship with a new lower bite roller.
3) errors caused by discharge or gapping of bite rollers to the prosthetic bed (of model);
These errors occur due to uneven squeezing bite rollers during fixation of the central relationship of the jaws. This may be not accurate fitting lower roller to the upper one, uneven heating of lower roller with a hot spatula, gap between wax base and a model. Often the result of such mistakes in the clinic is the lack of contact between the chewing teeth of one or both sides. It is defined by entering cold spatula between the chewing teeth . Meanwhile a spatula turn around its axis is made, and at the moment can be seen as wax bases closely gets adjacent to underlying tissues. Correcting the error is done by imposing heated wax plate in the chewing teeth area and bite redefinition.
4)braced basis during jaw central fixing relationship of the jaw: This may happen when occlusive rollers are not strengthened with arched wires or alveolar part of mandible is very narrow. It is seen during establishing such bases on the model that they are not firmly adjacent to it. In the clinic this error becomes apparent in the form of increased bite with uneven and uncertain chewing teeth papulose contact, gaps in front teeth. A mistake is corrected by redefinition of the central relationship of the jaws with new rollers, often with hard bases.
4) fixation jaw central relationship at shifting one of the wax bases.
For unfavorable anatomical conditions in the mouth (II degree of atrophy in the mandible and III degree of atrophy of the upper jaw) during fixation of the jaw central relationship a shift forward or back of lower or upper, which happens more often, wax bases with occlusion roller can occur. Checking prosthesis design, you can see the same picture as in the fixation of the mandible not in the central but in the front or back relationship, which was described above. A mistake is corrected, conducting re-redefinition of the jaw central relationship with new rollers made on hard bases.Further, on these hard plastic bases teeth are placed and prosthetic restoration is checked. Application of hard bases in this case is justified because they are stable on jaws, caot be deformed or displaced as wax ones.In all cases, when testing prosthesis design mistakes are revealed and corrected, a top model is obtained from an occludor or articulator and plastered in a new position.
After examination of the denture design in a clinic, dentures wax compositions are sent into the dental laboratory for final wax bases modelling and their replacement into plastic ones.
Fixing complete romovable denture in the mouth is a responsible clinical moment. The procedure of entering complete romovable denture does not require any special efforts from a dentist- orthopaedist, but the next steps related to this, require special attention and patience.
The procedure of fixing finished complete romovable denture begins with a detailed review of them. Reviewing dentures is begun with detecting visible to the eye and those inequalities that are defined palpatorily, and are immediately removed by a grinding method . After entering the prosthesis in the oral cavity it is checked whether the base does not fall from the prosthetic bed tissue and there are no balancing, and only then it is offered to the patient to close the teeth in position of the central relationship. Stability of dentures in upper jaw is checked by alternate manual finger pressing on the front and side teeth. The strength of locking valve in the field of soft palate is checked by folding back the cutting edges of upper teeth in lateral direction, on the lower jaw in the same way you assign the degree of base fixation in distal spots , in turns onthe right and left.
In addition, prosthesis fixation is checked by a patient himself, who performs set of movements of the mandible, mimic muscles and tongue. Basis of the prosthesis does not move from prosthetic bed during normal muscle contractions. While fixing the complete romovable denture lowering can be seen or increase of intercollar height, fixing the central relationship of the jaws in lateral occlusion, but often mistakes are made in case of fixation of the central relationship of the jaws, when the patient pulls the lower jaw in front occlusion. In the absence of closure in the region of the frontal or side teeth such dentures need to be remade. Defined preliminary teeth contacts, areas of increased pressure within the denture base, and areas where muscles are excessively overlapping prosthesis, are removed by grinding-off. While fixing the prosthesis side and front-rear movements must be checked, artificial teeth, at which the bite increases, particularly the canines must be grinded-off. Different actions are taken to keep maximum contact between the artificial teeth during movements. Front teeth, if they overlap considerably lower ones, are subjected to shortening.
Dentist-orsthopaedist after the above described manipulations should give the patient recommendations concerning the use of prostheses in the early days. Especially it should be done if the patient’s complete romovable dentures are made for the first time. Therefore it is necessary to emphasize that the prosthesis is a foreign body in oral cavity and it must be accepted this way. Often, after fixing the prosthesis a patient has a headache, nausea etc. In this case, it is recommended to withdraw dentures from the mouth. An important consideration during the use of prostheses is the first day. The patient is asked, if possible, during the first period not to remove the dentures from the mouth even at night. Of course the doctor very easily achieves a proper fit of the denture base to prosthetic bed tissue, easy input and output from his mouth, but over time the patient comes to the doctor complaining that the prosthesis causes pain in certain areas where they have contact with mucous membrane.
The elimination process places on the basis of the denture, which injures prosthetic bed tissue , is called a correction. Correction is conducted usually starting from the very next day after fixing dentures. The patient is asked to not use them in case of a pain, but about for 2-4 hours before visiting the doctor to enter the dentures in the mouth. Doctor during the review of oral mucous membrane easily determines the place of injury prosthetic bed tissue by edge of denture base. Denture places, which cause injury, are grinded-off and polished.
The number of corrections is different and can vary from one to ten. In the first period of prostheses use the patient must be supported psychologically, noting that he already speaks the words that it becomes easier to eat ,that after a while all the discomfort disappears. The described aspects of getting used to complete removable denture are called “adaptation””.
The term “adaptation” means adjustment, fitting. In terms of physiology orthopedic treatment of complete romovable dentures is a very serious interference in the human body and for the doctor to underestimate its complexity is unacceptable.
Complex mechanisms of adaptation can be better understood if refer to classic works of I.P. Pavlov of braking process.
Complete romovable dentures are unusual stimulus, the patient experiences it as a foreign body. Patients often are obsessed with feelings of prosthesis and its location in the oral cavity, which prevents them from performing the work and fully relax.
In the first stage together with all the listed deficiencies salivation increases, indicating the first phase of adaptation, which is called reflex irritation, and goes from 1 to 3 days. The nature of this reflex is unconditional, it recalls the reaction caused by the action of substances which are not accepted by the body. Vomiting reflex is caused by mechanical stimulation of receptor root of the tongue or soft palate. This reflex has a protective character. During the first week using the prosthesis the mentioned reaction to the irritation begins to subside, foreign body sensation changes. Salivation decreases, vomiting reflex disappears. These signs indicate that second phase of adaptation starts, entitled conditioned inhibition and extended for one further week.Patient ceases to feel the presence of the denture in the mouth, forgets about it and feels uncomfortable only when the prosthesis should be removed from the mouth. The third phase of adaptation extends to 30-35 days and is called extinction of conditioned stimuli and habituation to complete romovable denture. Valuable criterion for assessing adaptation to complete romovable dentures is adaptation.
E.I. Gavrilov (1978) believes that doctors should monitor patients for as long as there is no sure of the full adaptation to the onset of complete romovable denture. These measures, he calls the principle of completeness of treatment.
Often, doctors are asked the following question: whether to remove a prosthesis from oral cavity at night? If this question is not of only one person, then, in principle, dentures need to be removed from the mouth to decrease its staying on its mucosa. It is more difficult to solve this issue in relation to a particular patient. Before giving advice, the doctor must take into account the patient age, sex, marital status, as far as changing the aesthetic appearance of the patient in case of removing a prosthesis from an oral cavity. Especially it concerns younger patients, older patients in recommendations for removing a prosthesis from an oral cavity at night does not cause psychological stress.
Patients are recommended to rinse their mouth with decoction of oak bark, weak Nitrofural solution (1:5 000), solution of potassium permanganate. Do not use baking soda because it leads to breaking mucosa, which in turn will facilitate the emergence of prosthetic stomatitis.
The reaction of skin and oral mucosa at a dental laboratory plastics.
Used in dental practice materials inevitably lead to anti-living tissues and systems of the human body with allogenic materials. This ‘confrontation’ is represented most vividly in the mouth.
Dental materials have on living tissues of the human organism a direct or indirect (through ‘mediator’) effect. Healthy tissues are in dynamic equilibrium with balanced biochemical processes that keep tissues and structures and support their function. Allogenic material breaks this balance, causing in the tissues of humans different reactions, which tasks to eliminate these violations. These materials can in principle be toxic, allergens, carcinogens, mutagens, teratogenic. Under the influence of a strong irritant human body tissue reacts on the basis of nonspecific inflammation, ie normergic reaction, characterized by the classic symptoms: redness, swelling, fever, pain. In people who use dentures these signs occur rarely, but can be seen under a microscope. Virtually every field has a prosthetic signs ‘struggle’ with alien body. Normergic reaction manifests itself when the intensity of hazards than tissue tolerant ability (endurance) .During minor irritation of living tissue structures remain. Strong irritation causes destruction, destruction of tissue.
Description of the allergic reaction is the body or tissue of a living organism with appropriate sensitivity in contact with certain substances – antigen – antibody forming cells or sensitive.Repeated contact with antigen allergic reaction occurs.
Dental materials and their components are inferior antigens – so-called haptenes that can transform into a full-antigens resulting in connection with its own protein and have the ability to sensitization (sensitivity). Last is the background depends on the material dosage. First stage allergy can be compared with barrels, which gradually filled with water and suddenly overfills
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Plastic for making dentures
Acrylic plastic has been used for dentures for 30 years. In recent years have been developed a variety of materials – filled plastic materials based on diacrylic.
Toxicological aspects
Methyl ether of methacrylic acid – monomer – is poison. What, however, its toxic properties are only at high doses. For skin monomer is a strong irritant, which inhibits the protective barriers quickly, with prolonged exposure to integuments appear first contact eczema of eealergic type, then – allergic contact eczema.
Polymethylmethacrylate with toxicological point of view is not dangerous even if not achieved 100% polymerization and plastic is very little residual monomer.however long known that components of dental dental materials can cause as stomatopathy in patients and allergic contact eczema skin hand techniques. It is in these cases of allergic risk.
Allergic aspects
When suspecting allergies clinical examination and the application skin test are usually conducted. Predict allergens to which the patient or dental technician can answer the reaction of the relevant parts of the body are used. The following situations:
1. Sensitization of skin only.
2. Sensitization of skin and mucous membranes.
3. Sensitization of only mucosa.
Acrylic dentures while using absorb water, which contributes to destruction of plastics, inner tension appearance and pores lighting [15].Hardness and porosity, and poor care for dentures facilitate penetration of microorganisms in the oral cavity and lighting bases on its surface plaque, which contains carbohydrates, proteins, desquamated epithelial cells, leucocytes and others. Dentures are covered by dental plaque, the remains of food, epithelium desquamated cells .Most often food debris are under the bases of removable plate prostheses on upper jaw. As a result, favorable conditions for living fungi, especially the genus Candida albicans. Microorganisms plaque, disposal and recycling of food carbohydrates, create a critical pH value in the retention points.
How points Z.S. Vasilenko , the roughness as far various sizes, hills, spikes, sharp ridges, rough inner surface of the bases found in 25% plate dentures. Research by J.F. Roulet showed that the inner surface of such features are present in 74% of the bases of removable plate prostheses . During use quite often inflammatory infectious process takes place, as well as dentures and mucous membrane prosthetic bed (nozzle) get contaminated by microbial flora. Representatives of the microflora of saliva V.A. Khramov and L.M. Gavrikova divided into two antagonist groups: 1 – producers of urease (ureolitical), causing saliva increase by hydrolysis of urea and ammonia lighting. 2 – organisms that contain a set of glycolytic enzymes, which displace pH of saliva in the sour side fermenting sugar to organic acids..
Microbiological, biochemical and structural studies of plaque on removable dentures showed that it (denture plaque)is similar to the plaque on the surface of natural teeth. Essential for bacterial adhesion to different surfaces of prosthetic materials is the presence of free surface energy, and display them hydrophobic forces . Some research shows that in acidic medium the decrease of metabolic activity by plaque buildup in its liquid phase acid anions with high pH (acetic, propionic, oil), which act as effective buffers in the product stronger acids (eg, dairy) plaque microorganisms. Metabolic products Candida albicans (lactic acid, etc.) can cause pain in the prosthetic bed, burning .
V.A. Levkin notes that patients who do not remove the dentures at night or keep them dry at night, most often suffer from acrylic stomatithis. People, who do not remove dentures at night, have the number of colonies of fungus Candida albicans is 10 times higher than patients who use dentures only during the daytime. J. Kraft and co-authors in studies in vitro have shown that using the tools that improve the adhesion of dentures on the mucosa, is an increase in the number of colonies Sandida spesies.
With prolonged use of dentures microorganisms can penetrate the thick plastic to a depth of 2 – 2.5 mm .Among modern acrylate highest permeability for microorganisms has plastic “Etakril”. All are acrylic plastic on the surface of white coating, changed in color, with time and age is depot for oral cavity.It was found that strains of the genus Pseudomonos Aerobacter aerogenose destroy plasticizers that are part of the plastic, causing their collapse, which significantly worsens the basis material properties.Increase of microorganisms leads to increased enzymatic processes, contributing to the intoxication of the body.Irritating action of bacterial toxins cause unpleasant subjective sensation, hyperemia of the mucosa, so-called “effect bloodsicking banks”
Clinical stages
First visit
obtaining anatomical impressions (alginate material is usually used for making impressions ). Similar impressions are taken at partial defects of dentition
Second visit:
Obtaining functional impression (with thermoplastic or silicone mass). Is obtained by special samples
Third visit:
Determination of the central relationship of the jaws, the choice of form and color of teeth, prosthetic plane determination, drawing landmarks for setting the teeth
Fourth visit:
Check of prosthesis structures in the mouth
Fifth visit:
Fitting the prosthesis to the patient jaw and its correction
Laboratory stages
1. Getting a model from plaster, defining the boundaries of the denture base and making an individual spoon
2. Production of a model(better use highly strong varieties of gypsum). Manufacture of wax patterns with bite rollers
3. Strengthening plaster models in an occludor or articulator, torus and exostosis isolation, setting artificial teeth in wax basis
4. Final modeling of a denture base, denture plastering in a flask, replacing wax on plastics, polymerization, grinding and polishing the prosthesis
5. The final polishing of prosthesis
Devices that recreate movements of the mandible:
1. Occludors.
2. Articulators universal (Ghanau, Hite).
3. Articulators medium (Sorokin, Giza)
Methods of making individual spoons:
- individual spoon from standard base plates (AKR-P) •
- individual plastic spoon with hot wax immediate polymerization
- Cyto method of single-stage spoon
- photopolymerplastic spoon
- fast-hardening plastic spoon
- fast-hardening plastic spoon with bite rollers
Setting teeth methods during complete removable dentures manufacture:
- teethsettingontoothlessupperjawatpresence of lowerdentition
- classicteethsettingon toothless jaws
- anatomic teeth setting after Gizi
- teethsettingafter Vasiliev
- teethsetting after Ganau
- teethsettingat anterior jaw relationship
- teeth settingat prognathic jaw relationship
- teeth settingafter Sazur
- teeth settingon spheres
Gerber’s (1979) minimum requirements for complete dentures must be met when arranging artificial teeth. They are as follows:
- “Complete dentures should restore the facial appearance with a personalized and natural look.”
- “Complete dentures should preserve the residual tissue structures of the gnathodynamic system.”
- “Complete dentures should attempt to ensure adequate masticatory function and enhance clear phonation.”
Establishing Tooth Width
In keeping with Gerber’s requirements, the esthetic components of the anterior tooth arrangement must not be dissonant with a patient’s facial appearance.
Establishing maxillary anterior tooth width can be aided by observing the relative widths of the base (ala) and the bridge of the nose. For tooth selection that is harmonious with a patient’s facial appearance, the incisal width of the central incisor should reflect the width of the base of the nose, and the width of the lateral incisor should reflect the width of the bridge of the nose. That is, when the base of the nose is wide, the width of the maxillary central incisor should be wide. If the bridge of the nose is narrow, the lateral incisors should be narrow.
The line joining the distoincisobuccal corners of the central incisors and the base of the nose must be parallel.
Symmetry of the face should be considered in determining the vertical tooth axes, particularly the central incisors.
Selecting Tooth Forms
The shape and form of teeth should be selected in harmony with facial forms:
- Square face with square forms
- Oval face with oval forms
- Triangular face with tapered forms
Identification of facial form may be impaired in the edentulous patient due to inadequate soft tissue support and loss of vertical dimension of occlusion. For this reason, determination of facial shape should occur only when the occlusion rims are in the mouth and the appropriate vertical dimension and the patient is in centric relation.
Arranging Artificial Teeth
To assist compliance with Gerber’s requirements, there are seven anatomic landmark guidelines that should be followed when placing teeth:
Sagittal and frontal considerations |
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1. The incisive papilla is an invaluable reference point for correct placement of the maxillary anterior teeth and the anterior arch form. The maxillary anterior teeth lie to the facial of the incisive papilla. In the young, the line connecting the tips of the canines transverses the incisive papilla. As the alveolar ridge is increasingly resorbed with increasing years since loss of the teeth, the line moves posteriorly and may eventually pass through the posteriorly extent of the papilla.
2. The distance from the middle of the incisive papilla to the labial surface of the maxillary central incisor is typically 8 mm. Because this distance is fixed, the apparent curvature of the anterior arch form will increase as a person experiences more alveolar ridge resorption.
3. The labial surface of the canine is normally 10.5 mm from the lateral aspect of the anterior rugae.
Maxillary Anterior Teeth |
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o Tips of canines = width of nose o Width of centrals = width of philtrum |
4. The distance between the tips of the canines is the same as the width of the base of the nose.
5. Canines are immediately inferior to the side of the nose. They must not be positioned directly at the corners of the mouth when the patient smiles, so the “buccal corridor”—the facial surfaces of the premolars and first molar—can be visualized between the cuspid and the corners of the mouth.
6. The width of the central incisor approximates the width of the philtrum.
7. First premolars appear at the head of the “buccal corridor” and behind the canine.
Arranging Anterior Teeth
The buccal and facial surfaces of the prosthetic teeth should follow the facial contour established by the wax rim. In many cases it may be helpful to employ small amounts of either cream or powder denture adhesive during the try-in appointment to prevent the possible displacement of a baseplate that may be non-retentive due to distortion of the baseplate material, blocked-out undercuts, or the absence of a posterior palatal seal. Adhesive product should always be removed from the fitting surface of a baseplate before it is reseated on the master cast.
Selecting Tooth Shade, Form, and Alignment
Selecting tooth shade, form, and alignment is best accomplished prior to setting posterior teeth. Once the anterior teeth have been selected and set, the dentist needs to evaluate the midline in the mouth to ensure acceptable tooth placement.
Easier to judge before posterior teeth are set |
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The Smile Line
Once the midline is established as correct, the length, contour, and position of the incisal edges can be checked. The final evaluation of the anterior arrangement, which will include the gingival contours and margins, will be completed at the last try-in.
Final evaluation at last try-in
In this example, the central incisors appear too short and the canines appear too long.
Maxillary Anterior Teeth
A lifetime of gravity leads to slightly different soft tissue positions in older persons’ lips and faces. In the younger patient, approximately 1 mm of the incisal edge of the maxillary anterior teeth should be visible when the upper lip is relaxed. In an older patient, the maxillary incisal edge is likely right at the edge of the upper lip, and the mandibular anterior teeth will be more visible than one expects in a younger person.
At least 1 mm of incisal edge should show when the upper lip is relaxed |
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Principles of Posterior Tooth Arrangement
The following are the general principles of tooth arrangement:
- Denture teeth must be within muscular balance between tongue, lips, and cheeks.
- The occlusal plane should be at or below the height of contour of the tongue.
- Proper mastication and effective occlusion requires at least three pairs of antagonistic teeth on each side.
- A cusp-to-fossa relationship should be established whenever possible.
- During function, the forces on each tooth should have a stabilizing effect on the denture (independent of cross-arch equilibration).
Arranging Posterior Teeth
Proper selection of tooth forms and careful execution of the chosen occlusal arrangement can compensate for an unfavorable residual ridge. Cross-tooth/cross-arch balanced articulation is required during empty mouth movements, such as swallowing and speaking. Canine guidance is not advised for complete denture occlusion.
Balanced Occlusion
Shown is an example of the harmonious arrangement of the maxillary and mandibular denture teeth in a balanced occlusion relationship. Shown as well is an occlusal view of the maxillary posterior teeth. Note the mesial fossa of the first premolar and the palatal cusps of the posterior teeth lie along the line describing the alveolar ridge crest.
Occlusal view of maxillary posterior teeth |
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Facial View of Mandibular Posterior Teeth
Occlusal view of mandibular posterior teeth |
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Shown is an occlusal view of the mandibular posterior teeth in a balanced occlusion relationship. Note the buccal cusp tip of the first premolar and the central fossae of the posterior teeth lie directly over the line describing the alveolar ridge crest (which can be approximated by the line connecting the mandibular cuspid cusp tip to the medio-lateral center of the retromolar pad).
Lingual View of Teeth in Balanced Occlusion
Note dominant lingual cusp-to-fossa relationship |
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Note the dominant cusp-to-fossa relationships of the maxillary palatal cusp and the mandibular central fossae in this balanced setup. An observation of the setup from the facial would reveal a similarly tight intercuspation between mandibular buccal cusps and the maxillary fossae. With an arrangement such as this, both cross-tooth and cross-arch contacts are maintained during eccentric movements:
- On the working (discluding) side, the maxillary buccal cusps rise on the facial surfaces of the mandibular teeth as the palatal cusps are contacting the facial cusp inclines of the mandibular lingual cusps, providing the cross-tooth contact.
- On the balancing (non-working) side, the maxillary palatal cusps rise along the lingual cusp inclines of the mandibular facial cusps, providing the cross-arch contact.
A variation on the balanced occlusion is the lingualized occlusion. This arrangement is preferable for patients with severely resorbed alveolar ridges because the displacive forces between the opposing dentures in excursive motions are minimized. In lingualized occlusion, the cross-arch balance of the traditional balanced arrangement is preserved; but the “cross-tooth” relationship of balanced occlusion in which the palatal cusp/mandibular central fossae relationship is paired with a mandibular facial cusp/maxillary mesial fossae relationship is reduced to only include the former.
In a lingualized set-up, the mesial fossa of the maxillary first premolar and the palatal cusps of the maxillary posterior teeth lie along or lingual to the crest of the ridge, just as in a balanced denture setup. In some cases it may be advantageous for the orientation of the maxillary posterior teeth to slightly splay away from the palatal midline.
Mandibular Teeth
Occluded teeth viewed from the facial aspect |
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In the mandibular arch of a lingualized setup, the buccal cusp tip of the first premolar lies over the crest of the ridge as with a balanced setup. But the fossae of the remaining posterior teeth are lingually displaced. This results in the buccal cusps of the maxillary second premolar and maxillary molars being placed out of contact. The resulting intercuspation is restricted to the more lingual cusp/fossa pair; the occlusion is “lingualized.”
Lingualized Occlusion, Lingual View
Note the distinct lingualization of the cusp-to-fossa relationship.
The final try-in is an important step in the fabrication of a complete denture and must not be overlooked. At this stage, while the teeth are still set in wax and adjustments to the setup can be easily made, the patient and the dentist can evaluate the trial denture and make corrections if necessary.
Observe • Evaluate • Correct |
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The final try-in may take multiple appointments, depending on the patient’s esthetic and emotional needs.
Evaluating the trial denture at the final try-in includes:
- Inspecting the trial denture on the master cast
- Positioning the teeth on the articulator
- Checking anterior teeth for shape, form, color, and function
- Checking posterior teeth for shape, form, color, and function
- Checking the denture base form
- Evaluating function
Each of these steps will now be discussed in greater detail.
To inspect the trial dentures on the master cast, the dentist should:
Inspect the Trial Dentures on the Master Casts |
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Once these characteristics have been verified, the dentist needs to position the trial dentures on the articulator and evaluate the:
Position of the Teeth in Articulator |
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The general esthetic impression is best judged when the patient is standing or is sitting in an upright position. Once the articulated casts and the trial dentures on the articulator have been found acceptable, the dentist should insert the trial denture and evaluate the anterior teeth to be sure they display the correct:
Anterior Teeth |
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When the anterior set-up is deemed acceptable, the dentist then evaluates the posterior teeth for:
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To check the denture base form, the dentist then:
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Evaluating Function
Once the dentist is satisfied with the appearance and characteristics of the trial dentures under static conditions (with the patient at rest), many of the features just described must be assessed while the patient undergoes modest functional movements.
For instance, during the final try-in stage, the dentist must evaluate the vertical dimension for adequate space for the tongue during swallowing.
Additional aspects of the functional appraisal of the prosthesis will now be described.
Use of small amount of denture adhesive powder is helpful in building patient confidence at try-in stage
It is essential at this stage of prosthesis assessment that the patient build confidence iot only the esthetics but the function of the new denture as well. The inconvenience and embarrassment of a dropping maxillary denture or a floating mandibular interferes with the dentist’s appraisal of the trial prosthesis, and compromises the patient’s confidence in the likely successful performance of the new appliance. A small amount of denture adhesive can be used to help judge the appearance and speaking and other interocclusal functions, even as it dispels possible patient misgivings about the denture. Powdered adhesive, rather than cream adhesive, is advisable at this stage because the greater initial cohesion (“hold”) of cream-type adhesive may cause the operator to inadvertently distort the final wax try-in during removal.
Observing Facial Proportions
Observe the patient from every angle
To accurately appraise the quality of the prosthesis in function, the patient should be in a sitting position and should be observed from all angles. The dentist carefully watches the patient to check that the correct amount of the vermillion border is being displayed during speech, licking of the lips, and swallowing.
Maximum Intercuspation
Centric occlusion should correspond to articulator
Centric occlusion in the mouth and centric occlusion on the articulator must be identical. Should any discrepancy be evident at any stage of the trial denture appraisal, the following steps become necessary:
- A new bite registration is obtained;
- The mandibular cast is remounted;
- A second bite registration confirms the new mounting; and
- The teeth are reset according to the new interocclusal relationship and the intraoral and esthetic assessments are repeated.
Anterior Teeth
The dentist instructs patient to open the mouth slightly. The vermillion border should be supported by the denture teeth and not by the denture base. Younger patients should show more vermilion border and maxillary incisal edge than the older patient. When asked to pronounce “f” and “v” sounds, the patient’s lower lip should approximate the maxillary incisal edge effortlessly, and the enunciation should be distinct.
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The vermilion border should be supported by teeth |
Mandibular anterior teeth should be positioned to contact lower lip |
Mandibular Teeth
The mandibular teeth should be in contact with the lower lip, adjacent to the wet/dry border in a younger patient and extending superiorly about 1 mm in an older patient.
The dentist rechecks the vertical axis of the anterior teeth relative to the base of the denture to ensure the dominant angles of the face are in symmetry with the orientation of the incisors.
Lip Support
The labial surfaces of the flange and the anterior teeth provide lip support, but there are limitations to what can be accomplished with a denture.
For instance, thickening the maxillary anterior flange will not successfully remove vertical wrinkles in the upper lip and will distort the philtrum, giving it a “plumped” and unnatural appearance.
The facial surfaces of both the maxillary and mandibular denture should ideally feature subtle depressions to accommodate the orbicularis oris muscle, which will contribute to the retention of the prostheses. In the maxillary arch, the depression should be located entirely within the denture base, superiorly to the prosthetic teeth. In contrast, the depression in the mandibular prosthesis should be created between the teeth and the denture base.
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Lip support should come from labial surface of anterior teeth |
Teeth should be in muscular balance between cheek and tongue |
Cheek Contact
The cheeks and the tongue play key roles in positioning food onto the “occlusal table” formed by the mandibular teeth. As such, the proper amount and location of cheek contact is important for satisfactory function. The mandibular posterior teeth should be in a zone between the cheek and the tongue, impinging oeither.
Positioning Mandibular Teeth Relative to the Tongue
Difficult to evaluate
Chewing cannot be evaluated during the trial denture try-in. However, evaluating for adequate tongue space can be accomplished. The dorsum of the tongue should be approximately level with the occlusal plane.
When all of the preceding criteria have been checked and adjusted as necessary, the posterior palatal seal should be located prior to terminating the try-in appointment.
The maxillary denture should terminate at the most posterior extent of the hard palate, where it transitions into the moveable tissues of the velum or soft palate. This location can be determined by having the patient say Aah! (which elevates the soft palate) or by blowing through their obstructed nose (which forces it downward). The palatal tissues that do not move during either of the preceding actions are underlain by osseous tissue; the tissues that do move mark the extent of the soft palate. The line between them—the “vibrating line”—will correspond to the most posterior extent of the denture base.
The vibrating line is gently wiped with gauze to remove mucus secretions and then marked with an indelible pencil.
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Transferring marking to tissue-bearing surface of record base |
Determining the vibrating line |
Shortening the Record Base Border
The dentist then reinserts the maxillary trial denture. The patient is once again directed to blow through the obstructed nose; this will bring the marking on the palate into contact with the maxillary trial denture base.
The dentist then shortens the base to the indicated length and watches the soft palate as the patient says Aah. The movement of the soft palate should originate at the most posterior extent of the trial denture base. The dentist can further verify the border length in the mouth by palpating the soft palate with a finger or the end of the intraoral mirror handle. The hard palate should not be evident as the finger moves posteriorly.
The trial denture is then removed. The dentist should then gently palpate the mucosal tissues just anterior to the vibrating line to ascertain the degree to which they will tolerate the deliberate distortion introduced by the posterior palatal seal. This palpation should continue laterally to the pterygomaxillary area; the region immediately posterior of the tuberosities. This area is best palpated with the edge of the intraoral mirror.
Designing the Posterior Palatal Seal
Compensation for polymerization shrinkage
The posterior palatal seal will ensure the posterior extent of the maxillary denture, which has a tendency to move away from the master cast during the shrinkage that accompanies the heat curing of methylmethacrylate resin, remains in contact with the palatal tissues. If this contact is not maintained, the peripheral seal of the maxillary denture will be broken and the denture will be non-retentive. To maintain that contact despite the shrinkage of the denture, the tissue surface of the posterior portion of the denture is deliberately extended slightly into displaceable glandular and areolar tissue overlying the hard palate and the pterygopalatline notches. This is accomplished by removing a discrete amount of stone in the maxillary master cast when palpation has demonstrated the patient will tolerate it without discomfort.
Carving the Palatal Seal
A groove is carved and beveled anteriorly
While the patient is still present and the tissue consistency of the posterior palatal seal area fresh in the dentist’s memory, the posterior palatal seal should be carved into the master cast.
The shape of the posterior palatal seal will differ from patient to patient, according to the relative tautness or flaccid nature of the tissues. The groove that is carved into the master cast should be deepest in its most posterior extent (where the tissue is transitioning into the soft palate and is therefore most displaceable) and then beveled anteriorly, as guided by the findings of the intraoral palpation. The depth of the dam is typically 0.5-1.5 mm deep at its most posterior extent. Consistent with the findings from the intraoral palpation, the carving of the posterior palatal seal should continue into the tissues posterior to the tuberosities.
Patient Approval
The goal of the final try-in is to gain patient approval. Once the patient and dentist are satisfied with the product, the trial denture is ready to be processed.
An esthetic result in complete denture treatment is achieved through a deliberate combination of color, arrangement, and orientation of prosthetic teeth. Rather than a precise science, development of the trial denture requires a blending of qualitative and quantitative factors, each weighted according to patient’s preference and dentist’s experience. The occlusal scheme that is developed, in contrast, must adhere to certain clear principles of form and function in order to provide the patient with a result that is both esthetic and effective. Finally, the trial denture is generally evaluated at the same appointment at which the posterior palatal seal is designed. This course will review the factors that have been found to be most useful in selecting and arranging teeth, developing the occlusal scheme, and designing the post-dam.
The Construction of Complete Dentures
Complete dentures are constructed to restore normal speech, provide occlusal and facial support and adequate masticatory function. They should have a pleasing appearance, be comfortable to wear, and not prejudice the health of the supporting tissues. There can, however, be no guarantee that they will satisfy all these criteria for patients who have poor denture control skills, poor motivation, inadequate foundations, or intolerance to prostheses.
Preparation of the mouth prior to treatment and the design of complete dentures is the responsibility of the clinician.
CLINICAL PROCEDURES
Diagnosis and treatment plan
In order to formulate the treatment plan a medical and dental history should be taken and a clinical examination carried out, together with any appropriate investigations. Radiographs should only be taken when there are clear clinical indications. Previous dentures should be examined in conjunction with any complaints from the patient. Any pathological conditions should be investigated and appropriate treatment provided in order to render the oral tissues healthy before final impressions are made. Any elective surgery should be carried out at an appropriate stage.
There should be a clear treatment plan and expected outcome put to the patient, ideally in writing, so that they are able to make an informed decision of accepting the treatment proposed and related costs. It is well to remember that dentures are seen as goods and therefore subject to the Sale of Goods Act. This means that that they are suitable for the purpose for which they were made (i.e. to replace missing teeth) or according to the contract with explanation of any possible shortcomings.
Primary impressions
The requirements of the primary impressions are that they should accurately record clinically relevant landmarks of the edentulous mouth without excessive tissue distortion. They should be made in rigid stock trays modified as necessary to fit the form of the denture bearing area.
Maxillary impressions should record the following:
i) The residual ridge, tuberosities and hamular notches.
ii) Functional labial and buccal sulci, including the fraena
iii) The hard palate and its junction with the soft palate.
Mandibular impressions should record the following:
i) The residual ridge and retromolar pads.
ii) Functional labial and buccal sulci, fraena and the external oblique ridges.
iii) The lingual sulcus, lingual fraenum, mylohyoid ridge and retromylohyoid area. The impression should be recorded with the mylohyoid muscle in a functional raised position.
Where the impression is over-extended in relation to the functional depth of the sulcus, a clear indication should be made on the impression or resultant cast to help the technician in the construction of special trays.
Appropriate spaced or close fitting rigid trays should be requested in the laboratory prescription, depending on the type of impression material and technique to be used and the anatomy of the denture bearing area. The site for any stops, the type and position of the handle, as well as the amount of spacing should be stipulated by the clinician.
Working impressions
These should record the entire functional denture bearing area to ensure maximum support, retention and stability for the denture during use. Each special tray should be examined in the mouth and adjusted as necessary to satisfy the above requirements.
To ensure adequate lip and cheek support the maxillary impression should show an intact rounded record of the labial and buccal sulci, together with the fraena. It should extend posteriorly to the hamular notches and just beyond the junction of hard and soft palates. The mandibular impression should show an intact rounded record of the labial, buccal and lingual sulci, including the fraena. It should extend posteriorly to cover the retromolar pads.
Impressions should be boxed or the borders marked appropriately before the casts are poured in order to preserve an accurate record of the functional depth and width of the sulci.
Recording jaw relations (maxillo-mandibular relations)
The bases which carry the occlusal rims should be rigid and stable. The upper rim is modified to give correct lip support, which will vary from patient to patient. The incisive papilla provides a useful biometric guide to the prominence of the rim, its centre lying 8-10 mm palatal to the labial surfaces of the maxillary central incisors (in the natural dentition). Patients’ wishes, or previous satisfactory dentures, may sometimes dictate otherwise.
The length of the upper rim should be adjusted to indicate the level for the upper anterior denture teeth and the antero-posterior (occlusal) plane made parallel to the interpupillary and alar-tragal lines (unless facial asymmetry warrants an alternative). A centre line should be marked on the upper rim. This will usually be coincident with the midline of the face. High and low smile lines, and the corners of the mouth may also be indicated. It may also be advantageous to mark the centre line of the lower rim.
The occlusal vertical dimension should provide for most patients a minimum inter-occlusal clearance (freeway space) of 2-4 mm in the premolar region. It is established by adjustment of the lower occlusal rim and verified using various techniques of clinical measurement.
Failure to provide sufficient freeway space may lead to muscular discomfort, pain involving the denture bearing areas, and possible increased bone resorption. Excessive freeway space may lead to cheek biting, angular cheilitis, poor appearance and contribute to discomfort from the temporomandibular joints. Progressive incremental additions of acrylic resin to the occlusal surfaces of existing or diagnostic dentures may be necessary before a satisfactory occlusal vertical dimension can be established. It is essential to obtain a patient’s consent before making modifications to their existing dentures.
The horizontal jaw relationship to be recorded at the established occlusal vertical dimension is retruded contact position (RCP). This is a reproducible position at which the denture teeth are placed in intercuspal position (ICP). Once this position can be reproduced, the bucco-lingual width of the occlusal rims should be adjusted to identify the “denture space” (neutral zone). This is important in order to provide tongue space, facial soft tissue support, and denture stability. In some instances functional recording of the mandibular denture space may be appropriate using a suitable impression material on a stable base.
The occlusal rims must be located securely together in RCP in the mouth using an accepted technique. Small V-shaped notches may be cut bilaterally in the occlusal surfaces of the rims prior to the use of a suitable registration material. Wax as a recording medium in these circumstances is not generally recommended. Zinc oxide/Eugenol impression paste or rigid silicone registrations have the advantage of relocation if the rims become detached during transportation. The use of a face-bow may be desirable with a semi-adjustable articulator, although in the majority of situations an average value articulator will suffice. In this latter case, any change in occlusal vertical dimension will require new records to be made.
The prescription accompanying the registration should give details of mould, shade, material, and manufacturer’s brand of chosen teeth. A diagram may help the technician with the arrangement. The cusp form, material, and size of posterior teeth should be selected. The number of teeth to be used and their anatomical type should be recorded.
When setting up the teeth it is usual to limit the lower occlusal table to the horizontal part of the ridge and to avoid placing teeth over an inclined plane of the ascending ramus. Where patients have extremely resorbed lower ridges, and have had problems with previous lower dentures, the use of premolars rather than molars for the lower set up is suggested.
An impression of a previous denture may be helpful to the technician where a particular form of anterior tooth arrangement is to be repeated.
The trial insertion
The occlusal plane, occlusal vertical dimension, and RCP should be verified as correct. Tooth position and arrangement should provide adequate lip and cheek support and tongue space, allow clear speech, and give a pleasing appearance to the patient. Where alterations are required to the horizontal or vertical jaw relationship, a new recording will be required and a re-try necessary.
The position of the posterior palatal border of the maxillary base should be examined to ensure it is correctly extended just beyond the junction of hard and soft palate lying on displaceable but non-moving tissue. The foveae palati act as a useful landmark, lying 2-3 mm behind the posterior margin of the hard palate. It is the clinician’s responsibility to cut a post dam on the master cast in the appropriate position unless a functional post dam was incorporated into the final impression. The patient should be given the opportunity to see the trial dentures in place at this stage. It is wise for them to agree verbally (and ideally in writing) that the appearance is satisfactory.
The extension of the lower base onto the retromolar pad should be clearly indicated on the cast for the technician.
Insertion of the dentures
The denture bases should be inspected and any remaining surface blemishes or defects removed. Each denture should be inserted and assessed for retention, extension, appearance, and stability. Factors assessed at the trial stage such as lip support, speech, and horizontal and vertical jaw relationships should be reconfirmed as correct. Articulating paper or foil may be used to examine occlusion and articulation in the mouth, although this should be carried out with caution to avoid errors.
A pressure indicating paste or other suitable recording material may be used on the fitting surfaces of the dentures to indicate excessive tissue displacement.
A check record is a useful method for refining the occlusion, the dentures being re-mounted on the original articulator and adjustments carried out to provide correct articulation. It is strongly recommended that the processed dentures are routinely remounted on the articulator following deflasking (using the split-cast method), and the occlusion adjusted and ground in to overcome processing inaccuracies before returning to the clinic/surgery.
A check record may not then be necessary at the insertion stage, but could be valuable at the review appointment after the dentures have been worn for a period and the supporting tissues have adapted to them.
Instructions (both verbal and written) on the use and care of dentures should be given to the patient, and a review appointment made approximately one week later.
Inspection and review
At the review appointment, any adjustments should be made to the dentures in the light of the patient’s experiences or complaints. The denture bearing areas should be examined for signs of trauma even in the absence of patient complaints. The occlusion and articulation should be examined at this stage.
The importance of attending for regular review should be explained to the patient.
Addendum
The above guidelines are meant to cover techniques used in the different stages of complete denture construction. However, it is accepted that variations may occur, some of which are listed below:
· Copy/duplication techniques are extremely valuable for many patients, particularly the elderly. The techniques have been well documented2-5 and enable reasonably similar copies of previous satisfactory dentures to be made with a minimum of clinical visits.
· Making working impressions in a patient’s existing dentures may eliminate the need for primary impressions, special tray construction and occasionally jaw registration rims.
· Using appropriate impression materials, and by modifying stock trays, acceptable working impressions can be made without the need for special trays in some situations.
Disinfection
In all cases due regard should be given to the disinfection of all materials/prostheses which pass from clinician to laboratory and vice versa, according to health and safety requirements. This can be accessed from the following address:
Current practice and disinfection agents are subject to change and it is a clinician’s responsibility to keep up to date on such matters.
TECHNICAL PROCEDURES
The clinician is responsible for the provision of complete dentures. At each stage the dentist should provide a clear prescription for the laboratory. If the technical quality of the dentures is inadequate it is the clinician’s responsibility to have the problem remedied.
Primary casts and special trays
Surface moisture should be removed from the impressions after rinsing and before casting. Plaster of Paris and dental stone (50/50 w/w) are vacuum mixed with water. The impressions are cast using vibration to eliminate air bubbles and separated from the cast after 40 minutes. The cast should record the depth and width of the sulci and be surrounded by a “land” width of at least 3mm. The base should be 10 mm thicker than the deepest part of the impression. The “land” area should always be recorded unless the extent of the special tray has been indicated on the impression by the clinician.
Special trays are made according to the clinical prescription, which will stipulate the amount of spacing (if any) and stops. Handles must be designed to avoid distortion of the tongue or lips and finger rests are required in the premolar region on the mandibular tray to prevent the operator’s fingers distorting the soft tissues. The borders of the tray should normally extend to the deepest part (or slightly short if border moulding techniques are to be used) of the functionally recorded sulcus, or to an outline on the cast made by the clinician. In the maxilla it should extend posteriorly to the hamular notches and fovea palati ; in the mandible to the distal aspect of the retromolar pads.
Working casts and registration rims
Surface moisture should be removed from the impressions after rinsing and before casting. Dental stone in the correct measure is vacuum mixed with water and the impression cast. The thickness of the base and the width of the “land” is the same as for primary casts.
The base of the registration block should normally be made of a rigid material. Close adaptation of the base to the working cast is essential for stability in the mouth and accurate registration of jaw relations.
Registration rims are usually made of wax. The upper block should measure approximately 22 mm in height from the deepest part of the sulcus adjacent to the midline fraenum. The equivalent dimension of the lower block should measure approximately 19 mm anteriorly
Wax rims are positioned bucco-lingually in the same place as the lost teeth, according to the amount of resorption that has taken place. The occlusal surface of the lower rim passes posteriorly from its anterior edge to a point 2/3 up the retromolar pads. The upper rim should be created using an occlusal rim inclinator so that in the mouth it can easily be adjusted to be parallel to the alar-tragal line antero-posteriorly.
Mounting and setting up
The registration rims are mounted on a semi-adjustable or average value articulator (according to clinical requirements), preferably using the split cast technique. After noting the prescription for tooth arrangement, the maxillary anterior teeth are set up in accordance with the marked centre line, always conforming to the contour of the wax rim.
Unless the prescription says otherwise, or a neutral zone (piezograph) technique has been used, the mandibular posterior teeth are placed to conform to the buccal contour of the wax rim. It is wise, particularly with flat lower ridges, to avoid the most posterior tooth being positioned over an inclined plane, and to achieve this, the last tooth should be at the posterior extremity of the horizontal part of the ridge.
The teeth are adjusted to allow balanced articulation in lateral and protrusive excursions. Any part of the try-in base which was removed to facilitate registration is replaced unless this interferes with occlusal balance.
Processing and finishing
While in ICP on the articulator, the try-in is sealed to the casts with wax around the denture borders. Following processing, the dentures (still on casts) should be replaced on the articulator, by means of the split cast, and any processing errors removed by occlusal adjustment.
Finishing and polishing is carried out carefully to preserve the full width and depth of the recorded borders. Apart from the removal of imperfections, the fitting surface remains untouched. The completed dentures should be stored in clean water (with antiseptic as appropriate) after removal of traces of polish. Denture identification is a desirable option with complete dentures.
Check record
Where this is requested, it is preferably carried out on the original casts if possible. Failing this, the dentures may be remounted on an articulator using quick setting plaster and occlusal adjustments carried out.
Miraculous advancements in dentistry have been made since the inception of organized and intentional dental therapeutic intervention. Most recently, the advent and clinical refinement of dental implant therapy using root-form endosseous implants1 is an example of one such advancement that has revolutionized the profession’s approach to prosthetic replacement of missing teeth. Additional revolutionary advancements ride on the heels of the ever-progressive digital world, making once cumbersome procedures (eg, radiology, treatment planning, impression making, prosthetic design, and prosthesis fabrication) more readily available, and in some cases, more accurate and precise. In fact, advances in the modern dental world are occurring at such rapid rates that the challenge for practicing dentists is to keep up with the latest materials, devices, and procedures, as well as the evidence basis for their clinical implementation.
Despite the remarkable advances impacting so many facets of modern dentistry, pockets of routine treatment seem to have remained relatively stagnant over time. For many practitioners, the routine provision of complete denture therapy includes procedures that seem to have escaped the progresses of modern dentistry. When considering today’s conventional complete denture treatment, it is interesting to note that many of the clinical and laboratory materials and procedures used remain essentially unchanged from their historical inceptions.
While today’s complete denture therapy incorporates several significant improvements, fundamental concepts and techniques remain remarkably similar to historical treatment approaches. Positive advancements have been made in the area of materials and a resurgence of useful therapeutic devices results in improved complete denture outcomes. In order to achieve the fabrication of successful, well-accepted conventional complete dentures, practitioners should thoughtfully combine historically proven concepts with modern materials and devices. This article provides a brief overview of several clinical concepts and new materials that have been used to enhance modern complete denture therapy.
Edentulous Impressions
The number of available edentulous impression procedures is a varied as practitioners interested in treating edentulous patients. Subtle variations in the material or design of impression trays, impression material handling, border molding, management of the denture-bearing foundation, perceived delivery of pressure during impression making, patient-induced functional activity during the procedure, etc, will undoubtedly influence the resulting edentulous impression. Though most of these clinical procedures have enjoyed at least reasonable success, the relatively recent appearance of materials and devices unique to complete denture therapy may prove beneficial. New materials and new anatomically designed stock impression tray systems may facilitating accurate, pressure-controlled, definitive impressions without the need to develop primary casts and custom impression trays.
Practitioners should appreciate the following basic principles of impression making for edentulous patients:
- Impressions should extend to include the entire denture foundation within the health and functional tolerance of the supporting and limiting tissues.
- Impression borders should be in harmony with the anatomic and functional limits of the denture foundation and adjacent tissues. Therefore, impression borders should be identified using functional movements.
- Adequate space for impression material within the impression tray must be available.
- A guiding mechanism, or stop, should be available to accommodate the correct positioning of the impression tray relative to the edentulous ridge and associated tissues, particularly if multiple insertions of the impression tray are required.
- The impression tray and impression material should be made of dimensionally accurate and stable materials.
- Impression contours and dimensions should replicate intended contours and dimensions of the planned prosthesis.
A recently described method for edentulous impression making abides by these basic principles, uses readily available and anatomically designed stock impression trays, incorporates familiar vinyl polysiloxane (VPS) impression materials, and is a relatively time-conservative procedure. This modern edentulous impression system has been previously been described in great detail.
The unique anatomically designed stock edentulous impression trays used in this impression procedure permit several advantages. The trays come in an acceptable variety of sizes, can readily be subtractively adjusted using standard acrylic resin burs, and permit thermoplastic manipulations with shape-stable results. Additionally, the impression system incorporates a wide range of viscosity-specific VPS impression materials that are typically very familiar to most practitioners.
Again, readers are encouraged to review previously published descriptive literature for procedural suggestions for making edentulous impressions.
A variety of VPS impression material viscosities are available. Thoughtful application of viscosity-specific materials during the impression procedure and in different areas of the tray permits predictable tissue placement and control. VPS offers several potential advantages for making edentulous impression, including:
- Availability of different viscosities. For example, Aquasil Ultra Smart Wetting Impression Materials (DENTSPLY Caulk, www.caulk.com) is provided in five viscosities (ie, extra low, low, medium, medium-high, and high).
- Convenient delivery system (ie, automix cartridges).
- Predictable material adhesion between sequential layers of different material viscosities.
- Materials with various working times are available to satisfy operator preference. For example, use of a fast-set material permits the operator approximately 30 seconds to dispense the material into the impression tray, 1 minute to insert the tray into the patient’s mouth and perform tissue manipulations, and then 1 minute to final cure.
- The material is sufficiently elastic with clinically acceptable tear strength.
- Newer VPS materials have been chemically modified to improve wettability and hydrophilicity.
- The material is generally biocompatible and does not possess an offensive taste or odor.
Steps used to make these modern edentulous impressions include: (1) develop stops in properly adjusted stock impression trays using a high-viscosity VPS; (2) complete border molding procedures using a high- or medium-viscosity VPS; (3) trim tray overextensions using an acrylic resin carbide bur; (4) reduce border molding and tray stops by 1 mm to 2 mm in all dimensions and according to the dictates of selective pressure impression making to provide adequate space for the final wash of the impression material; and (5) introduce medium-, low-, and extra-low–viscosity VPS materials into the tray and make the definitive impression . Again, readers are encouraged to visit previously published detailed descriptions of this procedure for predictable clinical implementation.
The Central Bearing Device
The most appropriate relationship of the edentulous maxilla to the edentulous mandible when fabricating conventional complete dentures may be debated. However, most agree that achieving anatomically and physiologically optimal vertical and horizontal jaw relationships is important to successful therapy. It is the opinion of the authors that most clinicians skilled in modern complete denture therapy rely on centric relation as a physiologically stable and repeatable mandibular treatment position. Unfortunately, the ability to reliably record this interarch relationship is in part determined by the clinician’s detailed understanding of the anatomy and physiology of temporomandibular joint function, effective handling of clinical materials and devices, patient cooperation, and his or her skill and experience.
Historically, a number of techniques have been suggested for registering interarch relationships during complete denture therapy. These clinical techniques can be broadly classified as direct interocclusal records, graphic recordings, and functional records. A graphic recording method dating to the turn of the 20th century, but recently updated, involves use of a central bearing device. This device can aid the practitioner in the clinical achievement and registration of both horizontal and vertical jaw relationships and is particularly useful when muscle deprogramming of habitual mandibular closure is indicated.
Use of a central bearing device has been shown to be very precise. The concept has recently enjoyed a resurgence of interest due in part to newly developed instrumentation (Massad Jaw Recorder System, Global Dental Impression Trays, Inc., www.gdit.us). Advantages of this new central-bearing device include: ease of attachment to record bases using conventional light-activated laboratory resin and a unique pivoting central bearing pin for adjustment in all dimensions during the recording process.
This new central-bearing device comes complete with all of the elements necessary to assist in the registration of centric relation in various clinical situations, including dentulism, partial edentulism, full edentulism, small-arch diameter, and large-arch diameter .All components are disposable and setting the device up on record bases or paraocclusal bases is straightforward and time-conservative. The steps required to incorporate the new central bearing device into edentulous record bases are presented in great detail elsewhere
Complete Dentures
Complete dentures cover your entire jaw, either upper or lower. Some people call them “plates.” Complete dentures rest directly on the gum that covers the bone.
Complete dentures are custom made for you. The process involves multiple appointments, usually about five. The dentist first takes impressions of your mouth. At later visits, you and the dentist select the size, shape and color of the artificial teeth.
Learning to chew food with complete dentures takes patience and practice. You might have to cut your food into smaller pieces than you did when you had your natural teeth.
On occasion, one or more natural teeth are kept when a denture is made. These teeth usually have root canal treatment and are shortened to fit under the denture. This type of denture is known as an overdenture.
Dentists like to maintain a few natural teeth and replace the missing teeth with an overdenture if possible. This has several advantages:
- Your natural teeth help preserve bone.
- Your natural teeth bear some of the chewing pressure. This reduces pressure on other areas of the jaw.
- Your remaining teeth make the denture more stable and less likely to shift in your mouth.
- You feel a better sense of where your jaw is in space and the pressure you are placing on the denture if you have not lost all of your teeth.
- You may find it easier to accept wearing dentures if you have kept some teeth.
Lower dentures tend to be more difficult to keep in your mouth than upper dentures. That’s because the surface area of the lower jaw is much smaller than the top jaw. An upper denture covers the entire palate, which helps it stay in place. Therefore, an overdenture can be most helpful for the lower jaw. However, it is an option for almost anyone who has a few teeth remaining.
Teeth that will be preserved with an overdenture must meet certain standards of health. Canines and premolars are the most common teeth selected because of their root length and position in the jaw.
The teeth will have to be shaped to fit the denture. Shaping may expose the tooth’s living pulp. For this reason, the teeth usually need root canal treatment. This removes the pulp (the nerve of the tooth) and replaces it with filling material.
The teeth that will remain are covered with thin metal castings called copings. They fit into openings in the denture. Attachments also can be put on the copings to help retain the denture in the mouth. On occasion, a natural tooth can be kept in the mouth without a metal coping. If this is done, the dentist will prescribe fluoride drops. These should be used in the overdenture to prevent decay of the tooth.
Overdentures also can fit over implants instead of natural teeth. In fact, implants were first developed to give people “artificial roots” for bridges or dentures in the lower jaw. The denture can fit onto the implants directly, or onto a metal bar between implants.