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Laboratory stages of manufacture of complete dentures

June 8, 2024

Laboratory stages of nmanufacture of complete dentures. Peculiarities of choice nof materials for prostheses ipatients Gerontological profile.

INDICATIONS: the ntotal absence of teeth on one or both jaws.

RELATIVECONTRA-INDICATIONS: ndiseases of oral mucosa, allergic states.

Clinical nstages

First nvisit

obtaining anatomical nimpressions (alginate material is usually used for making impressions ). nSimilar impressions are taken at partial defects of dentition

Second nvisit:

Obtaining functional nimpression (with thermoplastic or silicone mass). Is obtained by special nsamples

Third nvisit:

Determination of the ncentral relationship of the jaws, the choice of form and color of teeth, nprosthetic plane determination, drawing landmarks for setting the teeth

Fourth nvisit:

Check of nprosthesis structures in the mouth

Fifth nvisit:

Fitting the prosthesis nto the patient jaw and its correction

Laboratory nstages

1. nGetting a model from plaster, defining the nboundaries of the denture base and making an individual spoon

2. nProduction of a model(better use highly strong nvarieties of gypsum). Manufacture of wax patterns with bite rollers

3. nStrengthening plaster models in an occludor or narticulator, torus and exostosis isolation, setting artificial teeth in wax nbasis

4. nFinal modeling of a denture base, denture nplastering in a flask, replacing wax on plastics, polymerization, grinding and npolishing the prosthesis

5. nThe final polishing of prosthesis

Devices nthat recreate movements of the mandible:

1. Occludators.

2. Articulators nuniversal (Ghanau, Hite).

3. Articulators medium n(Sorokin, Giza)

Methods nof 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 nteeth methods during complete removable dentures manufacture:

teethsettingontoothlessupperjawatpresence of lowerdentition
classicteethsettingo toothless jaws
anatomic teeth setting after Gizi
teeth setting after Vasiliev
teeth setting after Ganau
teeth settingat anterior jaw relationship
teeth settingat prognathic jaw relationship
teeth settingafter Sazur
teeth settingo spheres

Miraculous advancements nin dentistry have been made since the inception of organized and intentional ndental therapeutic intervention. Most recently, the advent and clinical nrefinement of dental implant therapy using root-form endosseous implants¹ nis an example of one such advancement that has revolutionized the profession’s approach nto prosthetic replacement of missing teeth. Additional revolutionary nadvancements ride on the heels of the ever-progressive digital world, making nonce cumbersome procedures (eg, radiology, treatment planning, impressiomaking, prosthetic design, and prosthesis fabrication) more readily available, nand in some cases, more accurate and precise. In fact, advances in the moderdental world are occurring at such rapid rates that the challenge for npracticing dentists is to keep up with the latest materials, devices, and nprocedures, as well as the evidence basis for their clinical implementation.

Despite the remarkable nadvances impacting so many facets of modern dentistry, pockets of routine ntreatment seem to have remained relatively stagnant over time. For many npractitioners, the routine provision of complete denture therapy includes nprocedures that seem to have escaped the progresses of modern dentistry. Wheconsidering today’s conventional complete denture treatment, it is interesting nto note that many of the clinical and laboratory materials and procedures used nremain essentially unchanged from their historical inceptions. A glance at key naspects of dental history illustrates this point.

While today’s complete ndenture therapy incorporates several significant improvements, fundamental nconcepts and techniques remain remarkably similar to historical treatment napproaches. Positive advancements have been made in the area of materials and a nresurgence of useful therapeutic devices results in improved complete denture noutcomes. In order to achieve the fabrication of successful, well-accepted nconventional complete dentures, practitioners should thoughtfully combine nhistorically proven concepts with modern materials and devices. This article nprovides a brief overview of several clinical concepts and new materials that nhave been used to enhance modern complete denture therapy.

Edentulous nImpressions

The number of available nedentulous impression procedures is a varied as practitioners interested itreating edentulous patients.^29-35 Subtle variations in the material nor design of impression trays, impression material handling, border molding, nmanagement of the denture-bearing foundation, perceived delivery of pressure nduring impression making, patient-induced functional activity during the nprocedure, etc, will undoubtedly influence the resulting edentulous impression. nThough most of these clinical procedures have enjoyed at least reasonable nsuccess, the relatively recent appearance of materials and devices unique to complete ndenture therapy may prove beneficial. New materials and new anatomically ndesigned stock impression tray systems may facilitating accurate, npressure-controlled, definitive impressions without the need to develop primary ncasts and custom impression trays.

Practitioners should nappreciate the following basic principles of impression making for edentulous npatients:

Impressions should extend to include the entire denture foundation within the health and functional tolerance of the supporting and limiting tissues.
Impressio 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 impressio tray are required.
The impression tray and impression material should be made of dimensionally accurate and stable materials.
Impressio contours and dimensions should replicate intended contours and dimensions of the planned prosthesis.

A recently described nmethod for edentulous impression making abides by these basic principles, uses nreadily available and anatomically designed stock impression trays , nincorporates familiar vinyl polysiloxane (VPS) impression materials, and is a nrelatively time-conservative procedure. This modern edentulous impressiosystem has been previously been described in great detail.

The unique anatomically ndesigned stock edentulous impression trays used in this impression procedure npermit several advantages. The trays come in an acceptable variety of sizes, ncan readily be subtractively adjusted using standard acrylic resin burs, and npermit thermoplastic manipulations with shape-stable results. Additionally, the nimpression system incorporates a wide range of viscosity-specific VPS nimpression materials that are typically very familiar to most practitioners. nAgain, readers are encouraged to review previously published descriptive literature³⁷ nfor procedural suggestions for making edentulous impressions.

A variety of VPS nimpression material viscosities are available. Thoughtful application of nviscosity-specific materials during the impression procedure and in different nareas of the tray permits predictable tissue placement and control. VPS offers nseveral 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.^38-41
The material is generally biocompatible and does not possess an offensive taste or odor.

Steps used to make these nmodern edentulous impressions include: develop stops in properly adjusted nstock impression trays using a high-viscosity VPS; complete border molding nprocedures using a high- or medium-viscosity VPS; trim tray overextensions nusing an acrylic resin carbide bur; reduce border molding and tray stops by 1 nmm to 2 mm in all dimensions and according to the dictates of selective npressure impression making to provide adequate space for the final wash of the nimpression material; and introduce medium-, low-, and extra-low–viscosity VPS nmaterials into the tray and make the definitive impression . Again, readers are nencouraged to visit previously published detailed descriptions of this nprocedure³⁷ for predictable clinical implementation.

The nCentral Bearing Device

The most appropriate nrelationship of the edentulous maxilla to the edentulous mandible whefabricating conventional complete dentures may be debated. However, most agree nthat achieving anatomically and physiologically optimal vertical and horizontal njaw relationships is important to successful therapy. It is the opinion of the nauthors that most clinicians skilled in modern complete denture therapy rely ocentric relation as a physiologically stable and repeatable mandibular ntreatment position.⁴² Unfortunately, the ability to reliably record nthis interarch relationship is in part determined by the clinician’s detailed nunderstanding of the anatomy and physiology of temporomandibular joint nfunction, effective handling of clinical materials and devices, patient ncooperation, and his or her skill and experience.

Historically, a number nof techniques have been suggested for registering interarch relationships nduring complete denture therapy. These clinical techniques can be broadly nclassified as direct interocclusal records, graphic recordings, and functional nrecords. A graphic recording method dating to the turn of the 20th century, but nrecently updated, involves use of a central bearing device. This device can aid nthe practitioner in the clinical achievement and registration of both nhorizontal and vertical jaw relationships and is particularly useful whemuscle deprogramming of habitual mandibular closure is indicated.

Use of a central bearing ndevice has been shown to be very precise.⁴⁷ The concept has recently nenjoyed a resurgence of interest due in part to newly developed instrumentatio(Massad Jaw Recorder System, Global Dental Impression Trays, Inc., www.gdit.us). nAdvantages of this new central-bearing device include: ease of attachment to nrecord bases using conventional light-activated laboratory resin and a unique npivoting central bearing pin for adjustment in all dimensions during the nrecording process.

This new central-bearing ndevice comes complete with all of the elements necessary to assist in the nregistration of centric relation in various clinical situations, including ndentulism, partial edentulism, full edentulism, small-arch diameter, and nlarge-arch diameter . All components are disposable and setting the device up non record bases or paraocclusal bases is straightforward and time-conservative . nThe steps required to incorporate the new central bearing device into nedentulous record bases are presented in great detail elsewhere

Dentures cahelp 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

Moderdentures 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 nproduced acrylic teeth available in hundreds of shapes and tooth colors.

The process nof fabricating a denture usually begins with a dental impression of the maxilla or mandible. This impression is used to create a nstone model that represents the arch. A wax rim is fabricated to assist the ndentist or denturist with establishing the vertical dimensioof occlusion. After this a bite nregistration is created to marry the position of one arch to the other.

Once the nrelative position of each arch to the other is known, the wax rim can be used nas a base to place the selected denture teeth in correct position. This narrangement of teeth is tried in the mouth so that adjustments can be made to nthe Occlusion. After the occlusion has been verified by the dentist with the npatient, and all phonetic requirements are met, the denture is processed.

Processing a ndenture is usually performed in a lost-wax process whereby nthe form of the final denture, including the acrylic denture teeth, is invested nin stone. This investment is then heated, and the wax is removed through a nsprue when it melts. The remaining cavity is then either filled by forced ninjection or pouring of the uncured denture acrylic. After a curing period, the nstone investment is removed, the acrylic is polished, and the denture is ncomplete.

Whether some nor all of the natural teeth are missing, there are several benefits from nreplacing them with complete or partial dentures. Replacing missing teeth helps nto fill out the smile by giving support to the cheeks and lips. Also, a more nyouthful, vibrant appearance is achieved by supporting facial muscles. nSpeaking, chewing, swallowing and smiling are also improved. Partial dentures nprevent teeth from shifting into the spaces created by the missing teeth. This nhelps prevent bite problems and decreases the likelihood of gum disease that is noften associated with crooked teeth.

When a ndenture is attached to dental implants, especially the lower denture, its nretention and stability are dramatically improved. Also, the bone loss that noccurs yearly with complete dentures is avoided.

Stages of nmaking complete removable dentures

Clinical stages

First visit

obtaining nanatomical impressions (alginate material is usually used for making nimpressions ). Similar impressions are taken at partial defects of dentition

Second nvisit:

Obtaining nfunctional impression (with thermoplastic or silicone mass). Is obtained by nspecial samples

Third visit:

Determinatioof the central relationship of the jaws, the choice of form and color of teeth, nprosthetic plane determination, drawing landmarks for setting the teeth

Fourth nvisit:

Check nof prosthesis structures in the mouth

Fifth visit:

Fitting the nprosthesis to the patient jaw and its correction

Laboratory stages

1. nGetting a model from plaster, defining the boundaries of the denture base and nmaking an individual spoon

2. nProduction of a model(better use highly strong varieties of gypsum). nManufacture of wax patterns with bite rollers

3. nStrengthening plaster models in an occludor or articulator, torus and exostosis nisolation, setting artificial teeth in wax basis

4. nFinal modeling of a denture base, denture plastering in a flask, replacing wax non plastics, polymerization, grinding and polishing the prosthesis

5. nThe final polishing of prosthesis

Delivery of ncomplete removable denture is a final stage of production of complete removable ndentures.This is fixation, correction, adaptation processes and recommendations non the use of the denture. The main condition for the denture holding otoothless jaw is anatomical retention, functional suction – physical and nbiological methods for fixing dentures on toothless jaws. So making a nfunctionally complete removable denture depends largely on correctly nobtained functional impression, reasonable choice of impression mass , nmethods of edge design of functional impression , wringing or nunloading mucous membrane, prosthetic bed, etc.

Removable ndentures are foreign body for a mouth and the patient, in addition, it ninadequately conveys chewing load. So study the process of adjusting to it is nvery important.

Fixing complete romovable denture in the mouth is a responsible nclinical moment. The procedure of entering complete romovable denture does not nrequire any special efforts from a dentist- orthopaedist, but the next steps nrelated to this, require special attention and patience.

The nprocedure of fixing finished complete romovable denture begins with a detailed nreview of them. Reviewing dentures is begun with detecting visible to the eye nand those inequalities that are defined palpatorily, and are immediately removed nby a grinding method . After entering the prosthesis in the oral cavity it is nchecked whether the base does not fall from the prosthetic bed ntissue and there are no balancing, and only then it is offered to the patient nto close the teeth in position of the central relationship. Stability of ndentures in upper jaw is checked by alternate manual finger pressing on the nfront and side teeth. The strength of locking valve in the field of soft palate nis checked by folding back the cutting edges of upper teeth in lateral ndirection, on the lower jaw in the same way you assign the degree of base nfixation in distal spots , in turns onthe right and left.

In addition, nprosthesis fixation is checked by a patient himself, who performs set of nmovements of the mandible, mimic muscles and tongue. Basis of the prosthesis ndoes not move from prosthetic bed during normal muscle contractions. While nfixing the complete romovable denture lowering can be seen or increase of nintercollar height, fixing the central relationship of the jaws in lateral nocclusion, but often mistakes are made in case of fixation of the central nrelationship of the jaws, when the patient pulls the lower jaw in front nocclusion. In the absence of closure in the region of the frontal or side teeth nsuch dentures need to be remade. Defined preliminary teeth contacts, areas of nincreased pressure within the denture base, and areas where muscles are nexcessively overlapping prosthesis, are removed by grinding-off. While fixing nthe prosthesis side and front-rear movements must be checked, artificial teeth, nat which the bite increases, particularly the canines must be ngrinded-off. Different actions are taken to keep maximum contact between the nartificial teeth during movements. Front teeth, if they overlap considerably nlower ones, are subjected to shortening.

Dentist-orsthopaedist nafter the above described manipulations should give the patient recommendations nconcerning the use of prostheses in the early days. Especially it should be ndone if the patient’s complete romovable dentures are made for the first time. nTherefore it is necessary to emphasize that the prosthesis is a foreign body ioral cavity and it must be accepted this way. Often, after fixing the nprosthesis a patient has a headache, nausea etc. In this case, it is nrecommended to withdraw dentures from the mouth. An important consideratioduring the use of prostheses is the first day. The patient is asked, if npossible, during the first period not to remove the dentures from the nmouth even at night. Of course the doctor very easily achieves a proper fit of nthe denture base to prosthetic bed tissue, easy input and output from his nmouth, but over time the patient comes to the doctor complaining that the nprosthesis causes pain in certain areas where they have contact with mucous nmembrane.

nThe elimination process places on the basis of the denture, which injures nprosthetic bed tissue , is called a correction. Correction is conducted usually nstarting from the very next day after fixing dentures. The patient is asked to nnot use them in case of a pain, but about for 2-4 hours before visiting the ndoctor to enter the dentures in the mouth. Doctor during the review of oral nmucous membrane easily determines the place of injury prosthetic bed ntissue by edge of denture base. Denture places, which cause injury, nare grinded-off and polished.

nThe number of corrections is different and can vary from one to ten. In the nfirst period of prostheses use the patient must be supported npsychologically, noting that he already speaks the words that it becomes easier nto eat ,that after a while all the discomfort disappears. The described naspects of getting used to complete removable denture are called “adaptation””.

The term n”adaptation” means adjustment, fitting. In terms of physiology northopedic treatment of complete romovable dentures is a very serious ninterference in the human body and for the doctor to underestimate its ncomplexity is unacceptable.

nComplex mechanisms of adaptation can be better understood if refer to classic nworks of I.P. Pavlov of braking process.

Complete nromovable dentures are unusual stimulus, the patient experiences it as a nforeign body. Patients often are obsessed with feelings of prosthesis and its nlocation in the oral cavity, which prevents them from performing the work and nfully relax.

In the first nstage together with all the listed deficiencies salivation increases, nindicating the first phase of adaptation, which is called reflex irritation, nand goes from 1 to 3 days. The nature of this reflex is unconditional, it nrecalls the reaction caused by the action of substances which are not accepted nby the body. Vomiting reflex is caused by mechanical stimulation of receptor nroot of the tongue or soft palate. This reflex has a protective character. nDuring the first week using the prosthesis the mentioned reaction to the nirritation begins to subside, foreign body sensation changes. Salivatiodecreases, vomiting reflex disappears. These signs indicate that second phase nof adaptation starts, entitled conditioned inhibition and extended for one nfurther week.Patient ceases to feel the presence of the denture in the mouth, nforgets about it and feels uncomfortable only when the prosthesis should be removed nfrom the mouth. The third phase of adaptation extends to 30-35 days and is ncalled extinction of conditioned stimuli and habituation to complete romovable ndenture. Valuable criterion for assessing adaptation to complete romovable ndentures is adaptation.

E.I. nGavrilov (1978) believes that doctors should monitor patients for as long as nthere is no sure of the full adaptation to the onset of complete romovable ndenture. These measures, he calls the principle of completeness of treatment.

nOften, doctors are asked the following question: whether to remove a prosthesis nfrom oral cavity at night? If this question is not of only one person, then, iprinciple, dentures need to be removed from the mouth to decrease its staying non its mucosa. It is more difficult to solve this issue in relation to a nparticular patient. Before giving advice, the doctor must take into account the npatient age, sex, marital status, as far as changing the aesthetic appearance nof the patient in case of removing a prosthesis from an oral cavity. Especially nit concerns younger patients, older patients in recommendations for removing a nprosthesis from an oral cavity at night does not cause psychological nstress.

Patients are nrecommended to rinse their mouth with decoction of oak bark, weak Nitrofural nsolution (1:5 000), solution of potassium permanganate. Do not use baking soda nbecause it leads to breaking mucosa, which in turn will facilitate the nemergence of prosthetic nstomatitis. n

Patient ninstruction 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 nInsertion

Denture ninsertion is seldom a topic requiring patient instruction at the insertioappointment. However, there are three possible nexceptions 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 retentio 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 the 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 nsituation meriting instruction on insertion occurs when the subject of denture nadhesive is brought up, whether by the patient or the dentist. This will be ncovered in more detail shortly, in the section titled “Protocol for the Use of nDenture Adhesive.”

Denture nRemoval

Patients nwith no prior familiarity to removing a denture should be instructed to break nthe seal by running one or both fingers along the full length of the flanges, nor by puffing out the cheeks (making a “P!” sound).

Cleaning nDentures

nPatients should be taught to remove their prostheses after each meal for a nrinsing and to clean thoroughly at least once daily. Thorough cleaning involves nbrushing and soaking.

Brushes nspecifically designed for denture cleaning should be recommended. These feature na wide handle for easy gripping; stiff bristles of one length on one side of nthe head (for use against broader, flatter denture surfaces such as facial, npalatal, and lingual surfaces); and bristles set in a pyramidal arrangement othe other side (for cleaning the tissue surface of the denture). Patients nshould be cautioned not to use toothpaste (other than toothpaste specifically ndesigned for use on dentures) as the high abrasivity of non-denture toothpaste nwill scratch acrylic, thereby, dulling and removing anatomic and esthetic ndetails from the denture surface.

Daily nsoaking in cleanser specifically designed for dentures is recommended for nassuring cleanliness and eliminating odors. Patients should be cautioned to nalways rinse the denture thoroughly after soaking in order to avoid ingesting ntraces of caustic cleaning agents.

Diet

Patients nshould be cautioned that chewing and swallowing with the new dentures is a nlearned behavior and lip- and tongue-biting are very common risks at first. To nensure comfortable eating while fostering confidence in the prostheses, npatients should be urged to continue to consume the quality and variety of nfoods they did prior to receiving the new dentures until those foods can be neasily consumed without discomfort from the dentures. As a patient gains skill nwith the prostheses, the range of foods can gradually expanded to include crisp nfruits cut in small pieces, nuts, and sandwiches.

Continue former diet
Add new foods as comfort increase

Night Use

Patients, nwhether first-time users or those receiving a new set, should always be ninstructed to leave their dentures out of the mouth for at least 6 hours per nday in order to allow the bearing tissues to rest. For most individuals, this nis most conveniently and acceptably accomplished during sleep. Whenever ndentures are removed for an hour or more, they should be thoroughly cleaned and nthen placed in water or a cleansing agent.

Recall

Patients nwith complete dentures likely have lower awareness of preventive dental nbehaviors than the average American consumer. As such, a deliberate, proactive neffort must be made to bring them back to the practice annually for a recall. nThis is important to re-evaluate and revise, as necessary, the prostheses and nto assess the health of the oral cavity. Over 90% of the 30,000 new cases of noral cancer diagnosed in America annually are found in persons over age 50 nyears. Denture use is correlated with advanced age, use of tobacco, and lower nsocioeconomic status—the three strongest risk factors for development of oral ncancer. As such, it is essential for dental professionals to establish and nstress a program of recall examinations for their edentulous patients just as nthey do for their patients who maintain their natural teeth.

The maicondition for the maintenance of dentures on toothless jaw is their anatomical nretention, functional suction – physical and biological method of fixation of nprostheses on toothless jaws. So making a functionally complete ndentures depends largely on obtaining functional impressiocorrectly,reasonable choice of impression mass, methods of ndesigning edges of a functional impression, streak or unloading nmucosal prosthetic bed, etc.

Removable ndentures are foreign body for the mouth and the patient, it also conveys ninadequate chewing load. So study the process of adjusting to it is very nimportant..

Processing nof complete dentures.

After ncompletion of plastics polymerization and complete flask coolness its nrelease of her dental pliers begins. Denture is taken out from the flask very ncarefully. First, take the lid and the bottom of the flask and pull entire unit nwith the pressing, and then gently release prosthesis of gypsum.Exemption from nplaster denture does not cause the difficulties, if good insulation of nplaster model surface was done .

Eliminating ninequalities, surface dissonances , residues of plastic on the surface nbasis is carried with various instruments – files,burins, nabrasives, drills, burs. Edges of the prosthesis are formed in curves, keeping nthe thickness and boundaries. Particular attention is given to treatment of nartificial teeth in their places of attachment to an artificial basis.

During nprosthesis processing with grinding wheel and another it is nnecessary to continually moisten the surface, which is treated to prevent noverheating and deformation of plastic.

Denture nsurface facing the oral mucous membrane, is treated very carefully, cutting off nonly visible remnants of plastic so as not to disrupt relief which must ncorrespond to microrelief of mucosal prosthetic bed.

For npolishing the denture base sandpaper is used with different grain size, which nis firmly fixed in drill paperhold. grinding is started with rough grinding npaper and finished with fine, getting their smooth surface.

Polishing is nbegun with the application of tapered felted folds , applying pumice mixed with nwater on the denture surface. After appearing smooth surface folds are replaced nwith rigid brush that allows to polish places difficult of access. For nproviding mirror shine on a surface a soft brush from threads and chalk nmixed with water or mineral oil is used. The surface of the prosthesis, facing nto the mucosa, and artificial teeth are polished with soft brushes with little neffort, to prevent abrasion of plastic and violations of relief form.

Denture nrepair.

Denture nbases repair is necessary if:

1)basis ncracks or complete fracture ,

2) partial nor full fracture of an artificial tooth,

3) clamp nfailure ,

4) removal nof an abutment tooth,

5) nreplacing the removed artificial tooth with an artificial one.

Depending othe nature of the damage repair may be done by obtaining an impression with or nwithout prosthesis. In the case when there is a crack or full fracture of the nbase and when it is not possible to make the prosthesis and stick together, do nnot get an impression. But if denture parts caot be composed or there is nlack of some of them an impression must be obtained along with prosthesis parts n. In the laboratory, after casting models or, as is said, “pouring”, nthe prosthesis parts are removed, their edges are grinded off, removing plastic nfrom each end 2-3 mm ; grinding off is conducted with dental mills. Othe boundary of the fracture surface is polished with files, burins and mills , ngiving roughness. Fragments are put on the model, the gap between the parts of nthe prosthesis is filled with wax and basis simulation is nconducted.

After the nsimulation model is plastered by direct method in flask basis, the entire nprosthesis is filled with liquid plaster, leaving open only part of the wax. nhaving cast a contraform after crystallization of gypsum flask is opened nand wax is smelted with hot water. After cooling flask plastic npreparation is made. For one correction on average 4.3 g polymer and 2 ml of nmonomer are needed. Before forming the plastic dough break lines are wiped with na monomer, the required number of plastic dough is imposed , covering its wet nwith cellophane, and pressing is done. After the control cellophane is removed, nplastic residues are removed , if necessary,plastic dough is added and nfinal pressing is done. Having checked the flask fixation on a clasp it is ndipped into the bowl with water and polymerization is done. After treating and npolishing denture again isfixed in the mouth.

In the case nwhen there is breakage or fracture of artificial teeth or clamps, when there is na need for clamps transfer to another place because of loss of abutment teeth nthe denture fining is done. Its essence is that an impression is obtained from nthe jaw with prosthesis put on it , and then model is cast.The positioof central occlusion is fixed with thwe help of blocks from the warm wax. nModel is plastered in occludor. The clamp full bending is done , and if nnecessary setting an artificial tooth is conducted. Model is plastered ia flask and wax is replaced on plastic by conventional methods.After the nprosthesis is treated, polished, grinded and sent to a clinic for fitting and nfixing.

Separately nwe will stiop at denture bases fining with selfhardening plastics. nThis method is widely used in clinical prosthodontics, but necessary to recall nthat the conditions of its application is to conduct polymerization in the napparatus under pressure to reduce residual monomer.

Descriptioof fining is to glue parts with dichlorineethan denture glue, which is ncontained in complex of selfhardening plastics ‘Protacryl’ and ‘Redont’.

Parts of the nprosthesis are placed along the fracture line, having glued them nbefore and are kept in this position for 2-4 min.

On cemented nprosthesis plaster model (‘pidlytok’) is cast. having smeared prosthesis nand plaster with vaseline , a contramodel is obtained with the new portion of ndensely mixed plaster. After, the prosthesis is removed from the model and broked nthrough bonding line, the fracture is grinded each side for 1-2 mm, making the nnotch.

Model nand contramodel are smeared with insulating varnish ‘Izokol’, then part nof the prosthesis is placed on the model.

Plastic ndough is prepared with selfhardening plastic, strewing powder in monomer ntu full, covering wuth glass pot on top to prevent weathering monomer.

The nprocess of maturation of plastic dough goes 3-5 minutes, depending on air ntemperature. Fracture line is greased with monomer. Polymerization nshould be in a special apparatus under pressure for 8-10 minutes. After nmachining, grinding and polishing dentures are passed on for fitting and fixing nin the mouth

Complete nremovable dentures correction.

The places nelimination process on the basis of denture, which injure prosthetic nbed tissue, is called a correction. Correction is conducted usually nstarting from the very next day after fixing dentures. The patient is asked to nnot use them in case of a pain, but about for 2-4 hours to visit the doctor nmust enter the dentures in the mouth.

Doctor nduring the review of oral mucous membrane easily determines the place of injury ntissue prosthetic bed with edge ofdenture base . Places of denture, which ncause injury, must be grinded off and polished.

The number nof corrections is different and can vary from one to ten.

In the nfirst period of prostheses for each visit the patient must be supported npsychologically, noting that he already speaks the words that it becomes easier nto eat that after a while all the discomfort disappear.

Denture nstomatitis is a common oral mucosal lesion in the United States and WesterEurope. Prevalence rates of 2.5-18.3% in adults aged 35-44 years or 65-74 years nare reported, with a predominance in the latter age group.Although patient age nand denture quality alone do not predispose individuals this mucosal condition, nthe odds of developing stomatitis, denture-related hyperplasia, and angular ncheilitis are increased almost 3-fold in denture wearers.Studies indicate nthat correlations may exist with the amount of tissue coverage by a maxillary ndenture, vitamin A levels, smoking of cigarettes, and not removing dentures.

It may be nthat you have very few symptoms at all but there are some things to watch out nfor. When you take your dentures out, the area underneath may be very red. It ncould be painful when you are putting your dentures in or taking them out. You nmay also find you have red sores at the corners of your lips or on the roof of nyour mouth. White patches can appear anywhere on the inside of your mouth. You nwill most likely have bad breath and your dentures will feel that they are nirritating the skin more thaormal.

If you nsuspect you have denture stomatitis, visit your dentist. He will be able to nrecognize the symptoms and prescribe a suitable course of treatment. If it goes nuntreated, your mouth will become very sore and it can ultimately lead to npoorly fitting dentures in the near future. It can also last for years if you do not nnotice it and get some treatment.

Pathophysiology

Mucosal nfactors have been implicated in the etiology of this condition, as have nbehavioral and manner-of-use factors in patients who wear complete dentures. Ithese patients, the nighttime wear of the prosthetic appliance is the most nsignificant factor.

Although the ndominant etiologic factor now appears to be fungal infection, other factors nmust be considered; these include the prosthetic device itself and also local nand systemic factors in patients who are aging and edentulous. The extent of ninflammation has been correlated with the presence of yeast colonizing the ndenture surface.Trauma has beeshown to have a role in the production of basement membrane alterations ninvolving expression of type IV collagen and laminin (alpha 1), thus indicating na possible relationship between these elements and denture stomatitis.Regarding the nprosthesis-related factor, an allergy in the form of contact mucositis is nsuggested. This reaction may be related to the presence of resin monomers, nhydroquinone peroxide, dimethyl-p -toluidine, or methacrylate in the ndenture. Furthermore, contact sensitivities such as this one are more commowith cold or autocured resins than with heat-cured denture-base materials.

Candida species have beeidentified in most patientsor in all patients,with Candida nalbicans being the predominant species isolated in addition to many other ncandidal species.Whether the norganism is merely commensal in this situation remains an issue because of the nfrequency of such organisms in the general population; the role of this norganism as the sole etiologic factor in denture stomatitis is unclear; nhowever, the presence of candidal organisms within the overall biofilm lends ncredence to its role in the development and maintenance of denture stomatitis.The etiology is nbest considered multifactorial, with the prosthesis considered the prime netiologic factor. The character of biofilm communities of denture wearers, however, nhas been shown to be distinctive when compared with healthy non – ndenture-wearing individuals.

International

Denture nstomatitis is a common oral mucosal lesion in Western Europe, Thailand, and nTurkey.

Race

No racial npredilection is recognized.

Sex

Sex-related nfrequencies differ among studies; therefore, no clear sex predilection is napparent.

Age

The disease nis more common in elderly persons than in young persons because elderly persons nare more likely to wear dentures and because their level of oral and denture nhygiene is reduced. In addition, age-related chronic disease (eg, type 2 ndiabetes mellitus), iatrogenic drugs, and age-associated immunocompromise ncontribute to this risk level.

Denture nstomatitis usually occurs in a patient who wears a complete maxillary denture nor a partial denture. The presence of deteriorating temporary soft denture nlining material and an improperly matched cleanser (which generally is the ncase) is associated with an increased presence of candidal organisms within the nbiofilm.

In almost nall patients, the duration of the lesion is usually unknown because of its nasymptomatic nature.

On rare noccasions, patients may complain of slight bleeding and swelling in the ninvolved area, as well as a burning sensation, a xerostomialike quality, or ncacogeusia.

Although nsymptoms are uncommon, the clinical presentation of erythema and edema in the npart of the palatal mucosa covered by the denture base is a diagnostic finding. nIntense erythema is the most common finding. Note the image below.

A variably intense erythema distributed over the part of the nmucosa covered by the denture base is diagnostic of denture stomatitis.

At times, aobvious fungal infection in the form of white surface colonies or plaques may nbe observed on the mucosal surface. Variably intense erythema, which may also nbe associated with scattered petechiae, is distributed over the mucosa covered nby the base of the denture but not beyond. Palpation of the involved mucosa nreveals 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 nTests and Interpretation

The diagnosis nrelies on clinical symptoms and history. Testing is not routinely performed.
n
nLab

Tzanck test of historic interest only; herpes simplex virus (HSV) culture
Serologic test for syphilis
CBC; cultures to determine secondary infection

nFollow-Up and Special Considerations If not resolving in 7–14 days or ngetting worse, consider CBC.
n
nDiagnostic Procedures/Other

Biopsy if persistent/recurrent/suspicious
Immunofluorescence is useful in the differential diagnostic between RAS and bullous ski diseases (3).

nPathological Findings Biopsy suspicious lesions or lesions that fail to nheal or chronically recur to rule out oral or hematologic cancer or vasculitis.

Treatment

Treatment of stomatitis depends on the causative factors. If cause nis allergic, identification removal of the agent is critical. For infectious ncauses, antibiotic or antifungal regiments. Steroidal anti-inflammatory drugs nfor systemic conditions with stomatitis manifestation. If the cause of nstomatitis is due to medical treatment or cancer therapy, treatment needs to be nmore aggressive.

Medication (Drugs)

Acetaminophe 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 ca 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)

Additional Treatment

General nMeasures

I 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

Complications

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 nof complete dentures.

After completion of nplastics polymerization and complete flask coolness its release of her ndental pliers begins. Denture is taken out from the flask very carefully. nFirst, take the lid and the bottom of the flask and pull entire unit with the npressing, and then gently release prosthesis of gypsum.Exemption from plaster ndenture does not cause the difficulties, if good insulation of plaster nmodel surface was done .

During prosthesis nprocessing with grinding wheel and another it is necessary to ncontinually moisten the surface, which is treated to prevent overheating and ndeformation of plastic.

Denture surface facing nthe oral mucous membrane, is treated very carefully, cutting off only visible nremnants of plastic so as not to disrupt relief which must correspond to nmicrorelief of mucosal prosthetic bed.

For polishing the ndenture base sandpaper is used with different grain size, which is firmly fixed nin drill paperhold. grinding is started with rough grinding paper and finished nwith fine, getting their smooth surface.

Polishing is begun with nthe application of tapered felted folds , applying pumice mixed with water othe denture surface. After appearing smooth surface folds are replaced with nrigid brush that allows to polish places difficult of access. For providing nmirror shine on a surface a soft brush from threads and chalk mixed with nwater or mineral oil is used. The surface of the prosthesis, facing to the nmucosa, and artificial teeth are polished with soft brushes with little effort, nto prevent abrasion of plastic and violations of relief form.

Denture nrepair.

Denture bases repair is nnecessary if:

1)basis cracks or ncomplete fracture ,

2) partial or full nfracture of an artificial tooth,

3) clamp failure ,

4) removal of aabutment tooth,

5) replacing the nremoved artificial tooth with an artificial one.