Dental examination of patients with complete tooth absence. Clinics of complete tooth absence. Classification of jaw atrophy. Assessment of the mucous membrane of the denture bed. Special oral cavity preparation for prosthetic treatment. Getting anatomical imprints of toothless upper and lower jaws

 

     The increased course of preclinical training in orthopedic dentistry is aimed not only at studying anatomy and physiology of the organs of the dentomaxillary systems, but also at deeper mastering of the practical skills, and thus at general improvement of training quality of dental students.

     Orthopedic treatment of patients is given for final restoration of the maxillodental system, reconstructions of the lost form of some organs of this system, their functional interrelations.

     The maxillodental system is organs and tissues interconnected functionally by anatomy, performing various but co-ordinated functions. It contains the hard tissues – bones of the facial skeleton, including the maxilla and mandible, masticatory and mimic muscles, salivary glands, temporomandibular joint – a paired organ – mobile connection of the mandible with the temporal bone of the skull.

     In the correctly formed maxillodental system the structure of each organ is precisely coordinated with its function. The compensatory process that is compensation of the impaired function due to activity of the intact organs begins to develop in the damaged maxillodental system, for example, influence of the environmental factors on an organism: physical, chemical, biological, social, with genetic defect or under the effect of local factors. But the compensatory process has a limit which is followed by rather steady deviation from the norm, having biologically negative meaning for an organism, resulting in development of a disease.

     Each disease is characterized by certain signs or a group of symptoms. There are subjective and objective symptoms.

     Subjective symptoms are symptoms revealed while questioning the patient, the unusual sensations which the patient began to experience. For example, difficulty in chewing food, pain, itching in the gums, dryness in the mouth, retention of food between the teeth, etc.

     Objective symptoms are found by the dentist during examination: inspection, palpation, instrumental and apparatus investigation.

     Sometimes it is necessary to apply functional methods of investigation to find out the function of the maxillodental apparatus: chewing tests, graphic records of movements of the mandible, investigations of the muscle biocurrents, etc.

     A disease can be manifested by one or several objective symptoms, one of which is characteristic only of the given kind of the disease, and others may be observed in other diseases. Examination of the patient is also aimed at making clear the symptoms, etiology and pathogenesis, course of the disease, his physical and mental condition, function of themaxillodental apparatus. Careful and thorough clinical examination of the patient will promote correct diagnosis, purposeful orthopedic treatment.

     While examining the patient, the dentist should know precisely significance of physiological norms, possible variants of the structure and functioning of separate organs of the maxillodental system, topography and functional interrelations. Thus he should not only detect the signs, but also be able to interpret them logically, determine the leading symptoms, basing on the examination of the patient. So the dentist should know well all sections of dentistry, a clinical picture of every nosologic form of the maxillodental system.

     Examination of the patient is made consistently under a certain plan and includes: the anamnesis (questioning of the patient), external survey, survey and examination of organs of the oral cavity; examination of the temporomandibular joint; examination of the muscles of the head and neck, laboratory and instrumental methods of investigation.

SUBJECTIVE METHODS OF INVESTIGATION

     Taking the anamnesis is the first investigation phase of the patient. The anamnesis consists of the following sections: 1) complaints and subjective condition of the patient; 2) anamnesis of this disease; 3) anamnesis of life of the patient.

     During the first visit of the patient the dentist listens attentively to the story of the patient about unusual sensations (complaints) which he began to experience. It is important to find out the earliest manifestations of the disease, character and peculiarities of its course, to know the cause of unusual sensations in patient’s opinion. In one case the anamnesis may be very brief and there is no necessity to go into detailed history of the patient’s life, in other cases, for example, when the patient has a feeling of burning in the mucous membrane of the oral cavity under the denture , the anamnesis and all investigations will be detailed with the use of apparatus and laboratory methods with participation of doctors of other specialities.

     It is necessary to listen to the patient attentively and patiently, at the same time concentrating his attention to the main, from his point of view, sensations, correctly specifying some moments by purposefully asked questions. All this can determine questions which are required for statement of the diagnosis, special or additional methods of investigation.

     While listening to the complaints of the patient it is necessary to pay attention to response of the patient in statement of complaints. It will help to get idea about the type of his nervous activity that is of great importance in choice of construction of a denture and the subsequent adaptation to wearing it, to faster establishment of mutual contact between the dentist and patients.

     During inspection it is important to obtain data about the onset of the disease, the cause of its development, its course before referring to the dentist, what treatment was applied, if it was, it is necessary to find out a kind and scope of the treatment.

     In some diseases it is difficult to establish the cause of their development. So, for example, pain, burning in the mucous membrane of the oral cavity under the denture can be caused by a badly made denture, a mechanical trauma or allergic reaction to the basic material. The same character of pain are observed in glossalgia, impairment of heat exchange in the tissues of the orthopedic bed, diseases of the gastrointestinal tract. Hence, pain may be caused by various causes, the mechanism of its development is also different.

     Sometimes during questioning it is possible to establish that deterioration of a condition of the maxillodental system occurred during some general disease or after it. Then there is a question, whether the revealed disease is independent nosologic form or is one of symptoms of other diseases (stomach ulcer, gastritis, diabetes, etc.). Therefore it is important to assess the general condition of the patient.

     The anamnesis of life. The anamnesis of life is a“the medical biography” of the patient. It is of great significant for understanding the causes, conditions of development of the present disease. For example, data about feeding (formula feeding, the use of the soft grated food during formation of milk and replaceable bite) can presumably specify the cause of abnormal development of the maxillodental system.

     The birthplace, peculiarities of the environment (lack or excess of fluorine in water) may be the cause of noncarious affection of the teeth in some people.

     Harmful working conditions, such as work connected with manufacture of acids, alkalis, coal-mining industry can promote development of pathological abrasion of the teeth.

     It is important to find out the sustained illnesses and presence of general somatic diseases at the moment of inspection as they also can promote development of pathological changes in the maxillodental system. The knowledge of their course peculiarities will also help the dentist to choose correct tactics in orthopedic treatment. So, in diseases of the cardiovascular system (myocardial infarction, stenocardia, insult) such injuring factor to this system as preparation of the teeth should be eliminated and it is better to recommend prosthesis by removable dentures. In presence of bronchial asthma, it is impossible to apply the materials having smell for taking inpressions (repin, thyodent, dentafol). They also should not be made relocation of the denture directly in the oral cavity. Otherwise it may cause an attack of asthma. Thus, on the basis of the anamnesis and subjective data of the patient, the dentist makes a presumable conclusion about the character and form of the disease. It is a working diagnostic hypothesis, which will promote the further purposeful investigation to specify the assumptions.

OBJECTIVE METHODS OF INVESTIGATION

     Detailed inspection of all organs of the maxillodental system is made for specification of the assumption of the disease and for better understanding of the disease. Data of the objective inspection reject or increase reliability of the assumptions of the disease. The objective inspection includes: external survey, survey and examination of organs of the oral cavity, radiological and laboratory (the analysis of blood, urine, saliva, smears and biopsy material, myography, rheography, etc.) methods of investigation.

     The objective methods of investigation are used, while going on questioning the patient as it is important to know subjective sensations. For example, whether the patient feels pain in probing, percussion, etc.

     External survey of the patient. After questioning survey of the face is started which is made imperceptibly for the patient. By the end of formation of the facial and brain skull, the face of the person gets individual features. The type of the face is influenced by development of the brain skull, respiratory apparatus, masticatory apparatus or musculoskeletal system. Four types of the face are distinguished accordingly: cerebral, respiratory, digestive and muscular .

     The cerebral type is characterized by strong development of the brain and skull. The high and wide frontal part of the face sharply predominates other parts therefore the face gets the pyramidal form with the basis directed up.

      The respiratory type is characterized by prevailing development of the middle part of the face, therefore the facial part of the head, neck and trunk get a number of prominent features. Cavities of the nose and its sinuses are strongly developed, maxillary sinuses are great, cheekbones protrude a little. The face is diamond-shaped, the nose is strongly developed in length, its back is quite often convex.

     The digestive type is characterized by prevailing development of the lower part of the face. The maxilla and mandible are excessively developed. The distance between angles of the mandible is great. The ramus of the mandible is very wide, massive, its coronoid process is short and wide, chewing muscles are strongly developed. The mouth is bordered by thick lips. The chin is wide and high. Due to strong development of the lower part of the face in relative narrowness of the frontal part sometimes the face gets the characteristic form of a trapeze.

     The muscular type: the upper and lower parts of the face are approximately equal, hair border is usually direct, the face of the square form .

     It should be also noted that the face of the person is disproportional: there is asymmetry in the structure of the left and right side. It is accounted for the fact that the left half of the brain skull is bigger than the right one, and the left half of the face is longer, the back of the nose does not coincide with the midline, the tip of the nose is shifted aside, with distance between the external corner of the eye and the corner of the mouth is not equal on both sides of the face, the right zygomatic  bone and the lower half of the maxilla are shifted to the right, the right canine fossa is deeper and narrower, the teeth of the maxilla and the lower part of the nose septum are shifted to the right.

     Division of the face into three parts is widely used in clinic of orthopedic dentistry: the upper, middle and lower thirds. The upper third of the face is located between scalp border on the forehead and a line connecting eyebrows. Borders of the middle part of the face are the line connecting eyebrows, and the basis of the nose septum. The lower third of the face is a part of the face from the basis of the nose septum up to the lower point of the chin.

 

 

 Division of the face into three parts is conditional as position of the points during life varies. For example, the scalp border of the head in different people is located unequally and moves with the years. The height of the lower third of the face also is changeable and depends on the kind closing and amount of the teeth preserved. Only the middle part of the face has rather stable points. Absence of constant anatomic reference points and strict functional division of various parts is of little value of the offered division of the face for regenerative orthopedics.

     Anatomic formations of the lower third of the face are of greater practical value 

     Expressiveness of the mental folds allows to assume presence of deep bite, distal displacement of the mandible with reduction of the vertical size of the lower third of face due to loss of the lateral teeth or their pathological abrasion. Decrease in the lower third of face is frequently accompanied by formation of perleches in corners of the mouth. Thus they become wet and have hyperemic look. Retraction of the lips speaks about absence of the frontal group of the teeth and if there is expressiveness of the nasolabial folds it is possible to draw a conclusion about complete loss of the teeth.

     The establishment of such deviations on survey is evidence of sharp reduction of the interalveolar height in the lower third of the face which are interrelated with absence of teeth-antagonists.

     It is important to distinguish two heights of the lower part of the face for the orthopedic purposes: height of relative rest and occlusionheight. The dentitions are not closed in height of relative rest, there is an opening between them from 1 up to 8 millimeters, depending on depth of incisal overlappings, the muscles of the face are in the condition of physiological rest. Occlusion height is characterized by tight closing of thedentitions under the condition of central occlusion, the muscles are in the contracted condition. Knowledge of these characteristics is important in construction of removable dentures.

     Survey of the face also allows to establish diseases the patient had before or concomitant general somatic diseases. For example, presence of cicatrices in the area of the upper lip is evidence of operative interventions for creft. Dryness of the skin integuments, presence of the skin folds pulled together in the area of the upper and lower lip with reduction of size of the oral fissure surmises the diagnosis of systemic scleroderma. Presence of cicatrices speaks about consequences of chemical or thermal burns. The face has a characteristic form in a number of endocrine diseases, e.g. acromegaly. Presence of moustaches and beard in women is characteristic of the disease of Ischenko –Cushing.

     A close survey of the face accompanied by purposeful questioning of the patient will promote a correct diagnosis both the basic and concomitant.

     Inspection of organs of the oral cavity. Inspection of organs of the oral cavity is one of the basic moments as detection of local manifestations of the disease determines further tactics of orthopedic treatment.

     Inspection is made in the following sequence: survey of the oral cavity, estimation of the teeth, estimation of the dentitions, presence of defects in them, interrelation of the dentitions, estimation of the mucous membrane of the oral cavity, estimation of the maxillary bones.

     First of all, pay attention to a degree of opening of the mouth. Restriction of opening of the mouth is probable iarrowing of the oral aperture as a result of muscular or articular contraction and will prevent carrying out of many manipulations in prosthesis (introduction of trays for taking impressions, imposing of denture, preparation of the teeth).

     Inspection of the teeth. Inspection of the teeth is made by a probe, mirror and tweezers. For convenience survey of the teeth is started with the right side of the mandible, then left with transition to the maxilla, continuing survey from the left to the right. On examination the mirror is held in the left hand, and a probe or tweezers – in the right one. The mirror enables to examine the tooth from different directions. Attention is paid to the position of the tooth, its shape, colour, condition of the hard tissues (affection by caries, fluorosis, hypoplasia, etc.), Stability of the tooth, a ratio of its extraalveolar and intraalveolar parts, position in relation to occlusion planes, presence of a filling, crown, their condition. The probe determines integrity of the crown parts, sensitivity of the tooth, depth of the gingival pocket. Simultaneously colour of the tooth is evaluated (reduction or absence of enamel shine, presence of chalk-like or brown spots, sulci). In depulpated teeth enamel has no characteristic shine, it is of a grayish-yellowish shade. The enamel happens to change in smoking, in workers connected with manufacture of acids, alkalis. The form of the teeth also changes in a number of diseases.

The important point in survey of the teeth is determinationof mobility of the tooth. There are physiological and pathologicalmobility of the teeth. The former is natural and is imperceptible to the eye. Its existence is proved by abrasion of contact points andformation of contact areas. Pathological mobilityis characterized by appreciable displacement of the tooth in small effort.

Mobility of the teeth is a sensitive indicator of the parodont condition, its supporting apparatus, that is of great importance for making the diagnosis, estimation of results of treatment or prognosis.

There are four degrees of pathological mobility of the teeth (by Entin). In the first degree displacement is in the vestribulo-oraldirection. In pathological mobility of the seconddegree the tooth is displaced in vestibulo-oral and mesiodistal directions. In the third degree the tooth, plunges in the socket on pressure and then comes back in the initial positionbesides displacement ina vertical direction. In the fourth degreeof pathological mobility the tooth has not only visiblemobility in three specified directions, but also can rotate.

Pathological mobility is always accompanied by presenceof pathological gingival pockets. Presence and their depth are determined by the probe.

Pathological mobility of the teeth is often accompanied by the expressedatrophy of the alveolar process thereforethe extraalveolar part of the tooth prevails over intraalveolar one. This is most typical of single-standing teeth. The increase in the external lever causes a functional overload of the tooth. A special preparationis requiredto use such teeth for prosthesis consisting of shortening of the crown part of the tooth.

The restored dental defect by a filling or cupping (crown) is carefully examined, paying attention to undamaged state of the filling, conformityof the artificial crown to requirements (dense adjacency of edges of the crown to the neck of the tooth, its integrity, change of colour, etc.).

Results of survey of the teeth are written down in the dental formula.Deciduous teeth are designated by Roman figures,permanent – Arabian.

Methods of percussion, probing and palpationare widelyusedwhile inspecting the teeth and making the clinical diagnosis.

Percussion is made by the handle of tweezers or dental surgery probe,slightly tapping on various surfaces of the tooth. On percussion of a healthy tooth the clear loud sound is heard and the patient does not react. In changes of the pulp, parodont there are painfulsensations of different intensity. Percussion is made cautiously, and pain in weak impact does not demand further increase in impact force.The teeth with the lost pulp, depulpated with the filled upcanals give an empty sound. Make percussion of the adjacent teethfor comparison. In extension of the periodontal fissures a muffled sound is audible. Dullness of the sound results from disorder of blood circulation in the periodont, development of edema. Edematious tissues as though absorb the sound. In the pathological process at the topof the root there is marked dullness of the sound on percussion.

  Probing is applied to determine depth of the carious cavity, character of the softened tissue as well as to study the conditionof the parodont. The concept of the parodont includes a complex of the formations having genetic and functional unity: the tooth, tissues of the periodont, bone tissue and periosteum, gum. At the neck of the tooth in the gum there is a circular ligament attaching the gum to the tooth and protecting the periodont from external damages. Impaired integrity of this formation leads to inflammation, various formations along the depth of pathological gingival pockets. An angular probe with blunt end is used for determination of the pocket depth, there are millimetric divisions on its surface. The probe is introduced ingingival sulci without effort from different directions of the tooth. If the probeplunges by 1-2 millimeters it is evidence of absence of the pocket or it is called a physiological gingival pocket. In immersing of the probe fromthe anatomic neck by half of the vertical size of the crown part of the tooth or more, we speak about a degree of atrophy of the alveolus.

Presence of the pathological gingival pocket should be differentiated with false gingival pocket which is formed in inflammation and significant edema of the marginal parodont tissues and in hypertrophic gingivitis. In appropriate treatment the mucous membrane of the gums comes to norm and the pocket disappears.

In a number of diseases there is a reduction of the gingival space therefore it is at the certain levelin relation to the tooth root. In this case we speak about clinical neck of the tooth.

Palpation is applied for determination of mobility of the tooth. Mobilityof the tooth is a symptom of many diseases: parodontitis,periodontitis, acute and chronic trauma arising due to inflammatory processes and edema of the surrounding tissues.

During survey and instrumental inspection absence of the teeth is also established. Thus by questioning we find out whether the tooth was extracted orprimary edentia takes place.

Assessment of the condition of dentitions. Inspection of the dentition is made separately. We determine: 1) number of the remained teeth; 2) presence and topography of the defect; 3) replacement of defects by dentures and theirkind; 4) character of contacts with the adjacent teeth; 5) form of the dentalarches; 6) a level and position of each tooth in relation to occlusion planes; 7) a kind of bite.

In the correctly formed maxillodental systemthe dentitions representa single whole both morphologically andfunctionally. The unity of the dentitions is provided with interdentalcontacts, alveolar process and parodont.

Interdental contact points in the frontal teeth are located near the cutting edge, and in the lateral – near the chewingsurface from the approximal sides. There are triangularspaces under them turned by the basis to the alveolar process which are filled in with gingival pupillae. Thus they are protected from damage by food. Besides, the pressure falling on the teeth,is distributed not only to the root of the tooth, but also to the adjacent teeth by interdental contacts, providing unity of the dentition.

With the years contact points are obliterated and contact platforms are formed instead of them. Their abrasion is a proofof physiological mobility of the teeth. A mesial shift of the teeth takes place causing shortening of the dentition up to 1cm.There is no impairment of continuity of the dental arch.

 While examining the dentitions we revealabsenceof a tooth (teeth), the cause of its loss. The tooth caot erupt because of absence of the permanentdental germ, then we speak about primary or congenital adentia.If loss of the tooth has occurred after eruption, we speak about secondaryor acquired adentia.

There is a lot of variants of edentulous defects.There was offerred a classification of dentition defects formed as a result of loss of the teeth.The most widespread classification in our country and abroad is that offered by Kennedy which takes into consideration position of defect in the dental arch and its extent. Defects of the dental arches are divided into 4 classes.

The dental archeswith bilateralend defectswhich have formedas a result of lossof chewing teethare related to the first class.

The second class is madeby the dental arches havingunilateralend defect.

The dental arches with intermediatedefectin the lateral part on one side are related to the third class.

In the fourth class only frontal teeth are absent.

If there are some defects of various classesin the dental arch, the dental arch is related to a smaller order class. For example, in the dental formula

0004300 0004560

There is a defect of the fourth and first class, in this case dentalarches are related to the first class.

In physiological norm each tooth has a certainpositionin relation to occlusion planes. Occlusion plane is a plane drawn from the cutting edge of the central incisor of the mandible to the top of the distal buccal tubercle of the second (third) molar. In orthognatic bitethe teeth are located in relation to occlusion surfaces in a certain order: cutting edges of the incisors, canines and distal buccal tubercle of the thirdmolar touch a plane, the first and the second premolars and molars are located below this plane. The central incisors and canines of the maxilla are by 2/3 mm (depth of the incisiveoverlappings) belowthe occlusion plane. Such arrangement of the teeth providescurvatureof the dental arch in anterior-posterior and lateral directions.

  Defects of the dentitions not onlybreak morphologicalunity of the dentitions but also leadto its complex reorganizationin the area of the defect at first, and then extends to alldentition.This reorganization is manifested by an inclination of the teeth asidedefect, vertical moving of the teeth deprived of antagonists,turning around the axis and other impairments which result in deformation of the occlusion surface.

      There are primary and secondary moving of the teeth.Primary movingbegins with eruption of the teeth and comes to an endwith formation of the dental arches. It is acceptedto consider change of the positionof the teethafter their eruption andformations of dentitions as secondary movingdue to defectsof the dental arches or as result of parodontitis, tumours of the jaw,traumatic occlusion

Most often there issecondary movingof the teeth which is made in variousdirections.

The following kinds of secondarymovingare most widespread.

The first group.

1.     Verticalmovingof the upper teeth unilaterallyor bilaterally.

2.     Verticalmovingof the upper and lower teeth unilaterallyor bilaterally.

3.     Mutualvertical displacement of the upper and lower teeth unilaterally orbilaterally.

The second group.

1.     Distal or mesial displacement of the upper teeth unilaterallyor bilaterally.

2.     Distal or mesial displacement of the lower teeth unilaterallyor bilaterally.

The third group.

1.     Inclination of the upper teeth to the palatal or buccal side.

2.     Inclination of the lower teeth to the palatal or buccal side.

The fourth group.

Turn of the tooth around of the longitudinal axis.

The fifth group.

Combined moving of the teeth.

Secondary movings of the teeth sometimes are brought to the forefront,determining character of all clinical picture, and determinerelativetypicalness of the therapeutic measures in different kindsof secondarymovings. Hence it is important to reveal them during clinical inspection of the patient.

Estimation of the condition of the mucous membrane of the mouth.The healthymucous membraneis pale pink colour in the area of the gums and pinkin other sites. In the pathological processes colour of the mucous membrane varies, there are various elements of affection on it. The most widespread of them: erosion – superficialdefect, aphtae- small sites of ulceration of yellow-grey colourwith bright red rim of inflammation, ulcers – a primary morphological element in the form of defect with rough and undermined edges and the bottom covered with grey coating.

The patient complains of reddening of the mucous membrane, bleeding, edema and burning of the orthopedic bed mucous membrane.

The cause of the specified symptoms can be:a mechanical trauma, disorder of heat exchange of the mucous membranedue tobad heat conductivity of the plastic denture,toxico-chemical influence of plastic components, allergic responseto plastics, systemic diseases (avitaminosises, endocrine diseases, diseases of the gastrointestinal tract, mycosises, etc).

During inspection it is important to establish character of affection of the mucous membrane, the cause which has caused this affection, stages of the disease(aggravation, remission). All these factors are of great value fora choice of the method of treatment and the material of whichdentures will be made as well asdetermination of term of the beginning of prosthesis. For example,in presence of erosion, ulcers of the traumatic character, prosthesisis made after their complete cure. On detection of manifestations of lichen rubor planus, leucoplakia and other chronic diseasesinthe oral cavity, prosthesis is made during remission.

On detection of the above-stated affections of the mucous membrane of the oral cavity, it is necessary to carry out additional investigations (the analysis of blood, cytology), consult with the dentist – therapist and specialist on skin and veneral diseases if necessary for differentiation. For example, traumatic ulcers should be differentiated from cancer and tubercular ulcerations, syphilitic ulcers.

The long-term trauma may lead to hypertrophyof the mucous membrane and formation of fibromas, papillomas.

Inspection of the maxillary bones.Formations of the bone bed are simultaneously investigatedduring surveyof the mucous membraneof the oral cavity and palpation. Attention should be paid to expressivenessof the alveolar process, the arch of the hard palate, maxillar tubers.The zone of the median suture for determination of the torus is necessarily investigated.

The sharp bone ledges are sometimes determinedin the area of edentulous alveolar process which have formed as a result of incompleteobliteration of sockets of the tooth and protruded interdental septum. Theseledges are painful, as the mucous membrane covering them is thinned; it is not expedient to make prosthesis without special surgical preparation of these sites.

In some cases it is possible to establish presence of boneledges (exostoses) on the mandible on the lingual sides on the right and the lefthalf of the jaw, their significant expressiveness demands specialpreparation before prosthesis by removable denture.

Inspection of the temporomandibular joint.The interalveolar distance decreases, positionof the mandible is changed causing changed position of the articular heads and all ratios of elements of the jointin formation of defects of the dentitions due to loss of masticatory teeth, pathologicalabrasion of the remained group of the teeth, diseases of the parodont. All thisleadsto disease of the joint.

Synchronism of displacement of the articular head in relation tothe articulardisk and articular fossa in movements of the mandiblecanbe disturbed in diseases of the muscles, especially external pterygoid muscles, central nervous system, diseases of the joint (arthritis, arthrosis). Therefore during inspection it is important to reveal the original cause of the disease of the joint as the techniqueof prosthesis and character of therapeutic treatmentdepends on it.

The most frequent complaints are pains inthe joint: swelling in the joint region, difficulty in opening orclosing of the mouth, pain, clicking, headache, burningof the tongue, dryness in the mouth. A method of palpationis used to examine the joints. For this purpose the index fingers of the hands are placed at the anterior surface of the tragus of the ear and the patientis askedto openthe mouthslowly. By palpation we determine the surface of the articularhead and a the posterior zone of the articular fissure. Moving fingers forward and pressing on the projection of the articular fissure and articular head, we determine painful points. Palpation is made in the closed denttition, at the moment of opening and in widely open mouth.

Sound of friction, crepitation in the joint may be associated with impaired release of the synovial fluid. A click or a crackle at the momentof opening of the mouth is more likely caused by reduction in height of bite and distal displacement of the mandible, and, hence, articular heads.Crepitation, crackle and click is also possible to determine by the methodof auscultation by means of phonendoscope. In pains in the joint, click and crackle, it is necessary to carry out additional investigations (roentgenography, rheography, arthography).

EXTRAORAL AND INTRAORAL EXAMINATIONS

The following is a concise overview of the components of the extraoral and intraoral examination. It stresses a systematic and consistent approach to these examinations. Systematic Extraoral Examination  

A review and assessment of the systemic health and pharmacological status of the patient is always done prior to any dental examination. The extraoral examination continues with observation of the head and neck, as well as observation of the sound of the patient’s voice and eye movements commencing from when the patient is first seated in the treatment room. Hoarseness in the voice may warrant further investigation if it has been persistent, since this may be an indication/suspicion of a growth within the larynx/oropharynx. Abnormal breathing may be a sign of anxiety or fatigue. Pupil size may signify a reaction to drugs or state of emergency as well as an indication of a disease state or inflammatory presence. The appearance of the face is further evaluated noting any asymmetry, swelling or discoloration. Inspection of the skin includes the color, texture, the presence of eruptions or swellings, or any abnormal growth. Observe all areas of exposed skin, paying particular attention to areas behind the ears and the back of the head and neck. Most people will have freckles, birthmarks, or moles; irregularities or a change in the shape, edge, color, and/or size can be a warning sign of skin cancer thus warranting further investigation.

Have your patients remove their eyeglasses to make certain there are no hidden growths or developments that would have otherwise gone unnoticed. The areas along the hairline and under the eyeglasses will require tactile palpation in order to discern or identify any swellings/growths.

Initial observation of head and neck, speech, and eye movements.

Examination of the temporomandibular joint.

 Bilateral palpation of parotid salivary glands.

Bilateral palpation of submental nodes.

 Bilateral palpation of submandibular nodes.

 Bilateral palpation of cervical lymph nodes.

 Bilateral palpation of supraclavicular nodes.

 Bilateral palpation of occipital nodes.

 Bilateral palpation of postauricular nodes.

 Bilateral palpation of preauricular nodes.

Next is the examination of the temporomandibular joint, utilizing a bilateral examination technique. This is accomplished by placing your finger pads over the joint just anterior to the ear; instructing the patient to open and close as well as move the jaw to the left and right; checking for any limitations or deviations upon opening, subluxation, any tenderness, sensitivity or any noises such as a grating, clicking, or popping.

The next area to be examined is the parotid salivary glands. The extraoral palpation of the parotid salivary glands is best examined using a bilateral technique, employing light pressure and placing fingers at the angles of the mandible over the parotid glands. Compare the bilateral findings for symmetry. Normal parotid glands are not palpable and exhibit no tenderness. Abnormal salivary glands may be painful, swollen, and indurated.         The lymph nodes are examined next with the clinician behind the patient and the patient’s chin slightly elevated. Areas of particular concern in a systematic examination can be found in the Table. It is important to inform the patient as to the relevance of the examination of the lymphatics of the head and neck before commencing this portion of the extraoral examination. In addition, one should indicate what areas of the head and neck will be examined. Due to the diverse multiculturalism that exists within our patient population, we must be culturally aware and sensitive to the different possible comfort levels of our patients.

Evaluation of the lymph nodes is done by a gentle rolling motion of the fingers, using the bilateral palpation technique. Note any enlargement, tenderness, lack of mobility, hardness, or asymmetry. If enlargement is detected, the examiner should determine the mobility and consistency of the nodes. Enlargement or lymphadenopathy may be attributed to either an infectious or inflammatory process or a malignant neoplasm. Clinical characteristics can help discern the difference.

In the broadest clinical terms, the enlarged node, if related to infection, is most often soft, freely movable, and painful. Also, the patient may have presented with an infection (or presence of inflammation) and may occasionally possess some knowledge of the etiology. Malignant neoplasm related nodes are normally fixed, particularly in the later stages, and they are generally not painful. One could compare the consistency of an infection related node to a blueberry or pea, whereas a malignant neoplasm related node is normally firmer in consistency, like a stone. Next, submental and submandibular nodes should be examined carefully. With the patient’s head back slightly, first examine the submental nodes. Instruct the patient to bite together lightly and place the tongue into palatal vault. This results in a tensing of the mylohyoid muscle, allowing for easier palpation of submental glands. Moving posterior toward the angle of the mandible and palpating directly below the line of the mandible are the submandibular glands.

         Another area to examine are the cervical nodes; both superficial and deep nodes. This set forms a complex chain of numerous nodes. Instruct the patient to turn the head in order to reposition the sternocleidomastoid muscle for ease of palpation and better access of both the superficial/deep cervical nodes.

         The supraclavicular nodes are palpated next, found superior to the clavicle in the hollow area or supraclavicular fossa directly above the collarbone. They drain a part of the thoracic cavity and abdomen. Virchow’s node is a left supraclavicular node, which receives the lymph drainage from most of the body (especially above the abdomen) via the thoracic duct; this node may serve as an early site of metastasis for various malignancies.

         The next nodes to be palpated are the occipital nodes. These are associated with the occipital artery at the posterior base of the skull. Using a bilateral technique, palpation is done directly below the base of the occipital bone. Reclining the patient’s head to the front, exposing the occipital area may facilitate better access for palpation of the occipital nodes.

         The posterior auricular, or postauricular, nodes are next in the systematic order of lymph node palpation and are usually 2 iumber. The anterior auricular or preauricular nodes are from one to 3 iumber and lie immediately in front of the tragus. Both pre- and postauricular nodes’ efferent vessels drain into the superior deep cervical nodes.

The thyroid gland, normally not detected by palpation, is examined next.

         An abnormal gland could be indurated, enlarged on one or both sides, or contain palpable nodes. When using bilateral palpation, palpation is done on both sides of the gland, noting any nodules or masses. Instruct your patient to swallow, which in turn will elevate the thyroid gland; allowing for an abnormality to become more apparent. Asymmetrical movement of the thyroid cartilage during swallowing might indicate that the gland is fixed to underlying tissues. If the patient is obese, it may be easier to palpate this area positioned behind the patient, having him or her turn the head toward the examining side. Suspicious thyroid gland findings should be referred to your patient’s physician for further evaluation.

Systematic Intraoral Examination

It is best to follow a systematic and consistent approach when performing the intraoral examination. The following is a suggested 7-step systematic approach:
         Step 1: Inspect the lips with the patient’s mouth both closed and open. The lips should have a normal/well-defined vermilion border and be even in coloration. Use the method of bidigital palpation to note any swelling, indurations or observed texture or color change. Documentation when dryness and/or unclear demarcation of lip vermillion and skin exist should be noted as “lip at risk” to flag the area for subsequent examinations. Also examine for loss of vertical dimension manifested often on labial commissures with the outcome being angular cheilitis. Further investigation to determine the causative factor behind the loss of vertical dimension would be warranted. Reinforce the need for sunblock protection, especially related to those patients who are active outdoors and have prolonged exposure to sunlight. Sunblock protection for the lips has had a positive effect on reducing the number of cancers related to the lip.

         Step 2: Inspect the labial mucosa using a visual and tactile method. This is accomplished with the patient’s mouth partially open, allowing examination of the labial mucosa and sulcus of the maxillary and mandibular vestibule and frenum.

         Step 3: Inspect the buccal mucosa using visual inspection and tactile palpation. This is best accomplished by using a bidigital palpation technique with the thumb placed against the buccal mucosa simultaneously with external palpation, noting any change in pigmentation, texture or diminished mobility or other abnormalities of the mucosa. Inspect the parotid gland from the intraoral aspect at this time as well as palpating both the maxillary tuberosities and retromolar pads.

         Step 4: Examine the gingival tissues. Observe attached and free gingiva on both arches, assessing for normal color and contour using digital palpation. Use a 2-x-2 gauze to dry the tissues to provide an enhanced assessment.

         Step 5: Inspect all surfaces of the tongue. The tongue is a very high-risk area for oral cancer as well as for candida infections. Candida infections can be an indication of an underlying systemic disease. The tongue should be examined thoroughly using both visual and tactile methods. Visual inspection alone is inadequate in its ability to identify early changes to the mucosal surface of the tongue. It is best to follow a systematic approach when inspecting the tongue, commencing with examination of the dorsum, then lateral borders and concluding with the ventral surface.

         The dorsum is the first area of the tongue to be examined. Ask the patient to protrude the tongue, moving from side to side, noting any abnormality of mobility or restriction of movement. With the patient’s tongue at rest, and mouth partially open, inspect and palpate the dorsum of the tongue to detect any swelling or fixed mass.

         Following inspection of the dorsum, examine the lateral borders. A common site for oral cancer is on this lateral aspect of the tongue. With retraction of the cheek, inspect the left and right lateral margins of the tongue. Handling the tip of the tongue with a piece of gauze will assist full protrusion and will aid examination of the more posterior aspects of the tongue’s lateral borders, including the lingual tonsils. With the tongue fully protruded (held and manipulated forward and side by side by the clinician for optimal visual access), inspect the posterior aspect and base of tongue using digital palpation along the lateral borders to identify any changes in tissue texture or consistency, noting any swelling/induration. If detected, compare with the opposing lateral border. Be suspicious of an abnormality that is unilateral.

         The last area of the tongue to be examined is the ventral surface. Instruct the patient to touch the roof of the mouth with the tip of the tongue. This will allow full inspection of the ventral surface of the tongue. Digitally palpate the ventral surface of the tongue to aid in any detection of growths, swelling or area of tenderness, as well as any color or texture changes. Observe for any asymmetry, comparing one side to the other.

         Step 6: Examine the floor of the mouth carefully, keeping in mind that this is another highly vulnerable area that requires close and thorough inspection. Areas are easily hidden from visual inspection. With the tongue still elevated, inspect the floor of the mouth for changes in color, texture, swellings, or other surface abnormalities. Using bimanual palpation, compress the floor of mouth against the opposite hand. This is the only effective way to identify any area of firmness or mass as well as locating any feeling of tenderness.

         Step 7: Inspection of the oropharynx and palatal tissues. Check the entire area of the oropharynx, examining the tonsil region including the uvula, tonsillar pillars, and palatine tonsils for presence, color, size, or any noted abnormalities. When examining the oropharynx, it is best to depress the tongue down toward the floor of the mouth using either a tongue blade or the back of the mouth mirror while instructing the patient to take a deep breath and hold or say “ah”. This method enables the clinician to gain better visual access of the oropharynx area. The soft palate should be visually examined next, accompanied by digital palpation of the hard palate, noting any asymmetries, swelling or mucosal changes.

ADJUNCTIVE SCREENING METHODS

The purpose of this article is to provide a pathway of decision making rather than an endorsement of a specific order of examination or the use of specific screening devices. There are a number of adjunctive screening technologies that are available and continue to emerge in the dental marketplace. It is vitally important to recognize that adjunctive screening technologies can provide valuable additional information (beyond the visual and tactile examination process) for further evaluation/assessment. A definitive diagnosis is obtained through a surgical biopsy to either rule out a malignancy or establish another diagnosis. This can sometimes be done in conjunction with other special testing methods.

         When lesions are found that are highly suspect, the need for a referral becomes evident. Adjunctive screening devices can serve as a critical component in our decision making, particularly those that aid identification of an abnormal finding before it becomes visible under traditional white light examination.

Many epithelial lesions typically start below the surface of the tissue, at the basement membrane, and can remain occult until they reach the surface, making earlier discovery more challenging. There are a number of light-based detection systems used to enhance visualization techniques. One must be careful to not be pulled into the marketing rhetoric rather than evidence-based research and scientific data. The weakest science involves tissue reflectance.

         A technique referred to as direct fluorescence visualization is supported by a strong body of scientific evidence related to its inherent ability to detect cancers and high-risk lesions including occult or nonapparent lesions or areas. This technique has a long history of use in other body sites such as the cervix, lungs, and colon.

         Direct fluorescence visualization works on the premise of the ability of human tissue to fluoresce due to naturally occurring fluorophores in oral mucosa under excitation with a specific wavelength and intensity. By utilizing special optical filters, the clinician is able to immediately view different fluorescence patterns in the oral tissue to help differentiate betweeormal and abnormal cellular activity. Wheormal tissue is exposed to the blue excitation light, it will emit an apple-green glow. As dysplasia begins to develop, there is a breakdown in the stroma and specifically in the connective tissue or collagen cross-links coupled with a reduction in the naturally occurring fluorophores greatly diminishing the ability of the tissue to fluoresce. This allows for real-time feedback of an irregular dark area, presenting a stark contrast to the surrounding tissue that appears as an apple-green glow.

 

LABORATORY AND INSTRUMENTAL METHODS OF INVESTIGATION

Laboratory-instrumental methods of investigation are consideredadditional as they are not always used. The purpose of theseinvestigations – establishment and confirmation of the exact diagnosis.

Radiological examination is based on taking andperusalof the X-ray pictures. Varioustechniquesare used for this purpose:

• Intra- and extraoral roentgenography;

• Tomography;

• Panoramicroentgenography

Roentgenographyis the most widespread andaccessiblemethod of radiological investigation of the teeth, alveolar processes, jaws, bones of the facial skeleton and skull.

Roentgenography gives valuable data of the condition of hard tissues of the crown and root, the size and peculiarities of the pulp chamber,root canals, width and character of the periodontal fissure , a conditionof a wall socket an alveolar process. With its help it is possibleto study alsoa structure jaws, mutual relation of elementsof the temporomaxillary joint and to reveal thus presence of pathological processes in the areas inaccessible to external examination, deformation of bones of the maxillofacial area.

In the X-ray picture the image is negative: the bone tissue has light shades, soft tissues, air spaces -dark. The enamel has a ligher tone than cement and dentin.Carious cavities have darkshades. The cavity of the tooth,periodontal fissures look as darklinesof  various configuration.

The intraoral roentgenogramallows to determine carious cavities, retention teeth,topographyof the pulp, patency of canals, presence of denticles, condition of the periapical tissues, hanging edges of the crowns, a degree of atrophyof the bone tissue of the alveolus.

Tomography.The radiologicalresearch convenientin studying structuralchangesof the alveolar process and jaws, has appeared insufficient in examination of the temporomandibular joint asit has a difficult structure and is located near the basisof the skull. Therefore it is almost impossible.to receive the X-ray imageof the temporomandibular joint by means of usual methodsof roentgenography

Usual roentgenography of the jointgives pictures only aboutrough changes in the joint(fractures, sharp deformationsof the articular surfaces in inflammatoryand degenerateprocesses). It is impossible to reveal thin changes at the initial stages of the disease by this methodand the joint looks normal on the roentgenogram.

All this has induced search for new, more perfect ways of radiological investigation of the joint.Tomography is related to such methods. It allows to receive the X-rayimage of the certain layer of the bone located at this or thatdepth. This method enables to study interrelationof elements of the temporo-maxillary joint at certain depth. It is also possible to reveal fine structural changes in the jointboneswith its help, caused both by general and local (dysfunction, trauma) diseases.

Panoramic roentgenography (panography).Panoramicroentgenography was offered by Blackman. It allows to receive a fullpicture of all teeth in the form of a panoramic picture of sufficient sharpnesswith 2 times magnification and considerably smaller irradiation than in usual picture. The survey is made during movement of the object and cassette, and the X-ray tube remains without movement.Only those layers of the object which are taken with identicalspeed with a filmare determined. These layers are shown with greater sharpness, andthe others are greased. The X-ray tube is placed behind,below the occiput. In  making a picture the armchair with a patientrotates clockwise, and the cartridge with an X-ray film- in the opposite direction.As a result a developed image of the jaws is obtained.Availability of a radiologicalmethod generated a notion of its harmlessness in some dentists. It has led to unreasonable indications to roentgenography of the teeth and alveolar process. Meanwhilethe X-ray irradiation is not harmless for an organism and it is necessary to rememberit.

On inspection of the patient before prosthesis it is necessary to make roentgenography of the teeth with affected parodontous membrane, teethwith fissures, teeth – abutments of bridge dentures, clasps, covered by crowns, teeth with pathological abrasion andteeth changed in colour, etc.

X-ray visiography.Lately there have been devised the devicescombiningX-ray installation and a videocamera, the so-called X-ray visiograph. They enable to receive the image of tissues of the tooth and soft tissues magnified 27 times onthe screen by means of a videocamera. Besides by means ofX-ray visiograph it is possible to receive a photoof the imagereceived on the screen.It distinguishes it from the usual X-raydevice as time is not required for development of the film.The image in the photois more precisethan on the X-rayfilm. X-ray visiographis placeddirectlyin the dentist’s room.

Methods of determinationof masticatory pressure.Absolute forceof chewing muscles.The chewingmusclesare related to force muscles, i.e. developing preferred force unlikeother muscles which can develop preferred velocity.

Absolute muscular force is determined by number of the tissues which are a part of the given muscle, i.e. the area of the physiologicaldiameter. The more fibers in the muscle, the moreis the areaof the physiological diameter,the greater forcethe given musclecan develop. Weber considers that “force of the muscle is proportionalto its transversal section under equal conditions”.

By Weber, a muscle with a diameter of 1 cm²develops the force equal of 10 kg.The muscles lifting the mandible have the followingdiameters of section: the temporal muscle – 8 cm², chewing muscle – 7.5 cm²,external pterygoid muscle – 4 cm². Proceeding from data of transversal section, absolute force of the temporal muscle is equal to 80 kg, chewingmuscles – 75 kg, external pterygoid – 40 kg, i.e. the general absoluteforce of muscles of one side is equal to 195 kg. The general absolute forceof chewingmuscles of the right and left sides makes 290 kg (195×2).

The absolute force of muscles established theoretically byaddition of indices of physiological diameters of the chewing muscles,lifting themandible, and multiplication of the received sum by possible development of force in each square centimeterof the transversal sectionsection of the muscle, naturally,does not represent the facts. In concomitant work the chewing muscles cannotdevelop the force equal to 290 kg. Absolute force both of chewing andother muscles, develops only at the moment of danger and mental shock, and in the ordinary life the person does not have necessity to develop such force in chewing food. Therefore researchersare interested in pressure which develops onthe certain site for nibbling and chewing food of definite consistence (meat, bread, crackers, etc.). It is also important to know endurance of the parodont of certain teeth to chewing pressure. It would allow to be guided in permissible load in prosthesis with bridge and other dentures.

Endurance of the parodont is measured by special devices –gnatodynamometers. A gnatodynamometer was offered for the first time in 1893by Bleck. Then other devices have been designed, based onthe same principle. The device is supplied by a platform for the teeth. In closing of the mouth the teeth transmit certain pressure tothe springthrough the platform which is registered by the scale inkg. Last years new designsof gnatodynamometry were offeredwith strain sensores.

The method of gnatodynamometry proved to be insufficiently exact asthese devices measure endurance of the parodont to the pressure havingonly one direction (vertical or lateral). In actionof force on the tooth the pressure expands and effects the abutment and adjacent teeth.

Static methods of determination of chewingefficiency.For determination of endurance of the parodont and role of eachtooth in chewing special tables are offered which receivedthe name of statistical systems of accounting of chewing efficiency. A degree of participation of each tooth in the act of chewing is determined by a constantvalue expressed in percentage.

While drawing up the specified tables the role of each tooth is determined by size of the chewing and cutting surface, amount of roots, size of their surface, distance at which they are movedfrom the jaw angle. Some tables are offered constructed bythe sameprinciple (Dushange, Vustrov, Mamlok, etc.).The static system of accounting of the chewing efficiency developed by N.I.Agapov is widely used in ourcountry.

 

 Chewing coeeficients of the teeth by N.I.Agapov

N.I.Agapov has accepted chewing efficiency of all dentalapparatus for 100 %, and for unit of chewing ability andenduranceof the parodont – a small incisor, comparing all other teeth with it. Thus, each tooth has constantchewing coefficient in his table .

N.I.Agapov’s has made the amendment in this table, recommending to take into consideration teeth-antagonistsin calculationof chewing efficiency of the remaining dention. For example, in the dentalformula

654001 1 100345

654001 100345

Chewing efficiency is equal to 58 %, and in the dental formula

654001 100345

000000 I 000000

it is equal to zero as there is no pair of antagonists.

As it is already noted, in Agapov’s system value of each toothis constantand does not depend on condition of its parodont. For example, the roleof the canine in chewing is always determined by the same factorirrespective of, whether it is steady or has a pathologicalmobility. It is serious lack of the offered system.

V.Yu.Kurljandsky offered a static system of the accounting of the conditionof the basic apparatus of the teeth, named a parodontogram by him.The parodontogram is received by recording data about eachtooth in the special table.

A conditional coefficient is given toeachtooth with healthy parodont in the parodontogram like in other static schemes. Thesecoefficients are made on the basis of proportional ratioof endurance parodont of different teeth to loading thatwas determined by gnatodynamometry in unaffected parodont.The coefficient of endurance of the parodont to loadingis accordingly loweredat different degrees of socket atrophy in different teeth.In atrophy of IV degree the parodont does not possessendurance to loading(the tooth is subject to extraction).

It is assumed in practice that the parodont of the tooth is able to indure twice more loading than loading in processing food.

FUNCTIONAL METHODS OF INVESTIGATION

Functional chewing tests.Static methods appearedto be poorly acceptable to determination of a disorder degree of chewing efficiency not only because theyinsufficiently preciselydetermine a role of each tooth in chewing and perception of chewingpressure but also because they do not consider a kind of bite, intensityof chewing, force of chewing pressure, influence of saliva on grinding of food, a role of the tongue in the mechanism of formation of food bolus. Therefore, there were offered functional (chewing) tests allowingto receive more correct concept about dysfunction of chewing.

Chewing force of the muscles.In physiology it is force which can be developed by all chewing muscles lifting the mandible. According to Weber’s data it is equal on an average to 390 – 400 kg (the physiological diameter of all three pairs of muscles-elevatorsof the mandible is equal to 39 cm², and 1 cm² of the area of the physiological diameter of the muscle can develop force of 10 kg). Hence all chewing muscles can develop force of 390-400 kg. The physiological diameter of the internal pterygoid muscle is equal to 4.0 cm², proper chewing – 8 cm², temporal -7.5 cm², i.e. the internal pterygoid muscle can develop force of 40 kg, proper chewing -75, and temporal-80 kg, all in all 195 kg on one side, and 390 kg – on both.

Chewing pressure is force realized by chewing muscles on one side of food grinding. There is vertical and horizontal chewing pressure. It is measured by kgs by means of gnatodynamometer.

Chewing efficiencyis a degree of crushing food by the teeth. Chewing efficiency is measured by percentage in comparison with the intact maxillodental system which chewing efficiency is accepted to be 100 %.

Chewing test by Christiansen is thefirst of techniques for determination of chewing efficiency. He investigated a degree of crushing of certain food – a hazelnut or a coconut. 5 g of a nut were taken for the test, after 50 chewing movements the patient spat out masticated mass on a small sieve with a diameter of 2.4 mm. The mass was sifted, the leftovers were weighed. The leftovers divided by 5 g and multiplied by 100 % – made the factor of Christiansen. 

Chewing test by Gelmanis a modified technique of Christiansen offered for estimation of the functional condition of the maxillodental system and determination of chewing efficiency. The test is based on the author’s supervision that the intact dentomaxillary system crushs 5 g of almond for 50 sec. till the size of the particles siftedthrougha 2.4 mm sieve. In presence of dentition defects – for 50 sec. but the almond is not completely crushed, and its part remains on the sieve.

Technique: 5 g of almond is weighed and given the patient to put in the mouth and to start chewing after a signal “begin”. The beginning of chewing is marked by a stop-watch. In 50 sec. the examined stops chewing on the signal “stop”, spits out the chewed mass in the cup, rinses his mouth and spits out water in the same cup. 5-8 drops of 5 %solution ofmercuric chloride are added for disinfection. The ontents of the cup is filtered through gauze and evaporated in water bath. Then the mass is carefully sifted through the sieve, often stirring, it is better to use a wooden stick. The part of the mass which have remained on the sieve is accurately poured onto the watch glass, and weighing is made. A percent of chewing disorder is calculated by the following formula. Suppose there was a mass of 2.62 gon the sieve, then:

5 : 2.82 = 100:X, where X-percent of chewing disorder

х: 2.82 = 100 : 5

х= 2.82х100        282:5 = 56.4 %.

Chewing efficiency makes 100 %– 5б.4 % = 43.6 %.

Chewing test by I.S.Rubinov  

     Itis offered for estimation of the functional condition of the maxillodental system. Various products with different physical properties are applied (a nut, a cracker, fresh bread, etc.). On the basis of the chewing test it is revealed that in deterioration of conditions of the dental system time of chewing in processing firm food substances (nut) before swallowing is extended and despite it food particles of rather big size are swallowed. It is known that in adults with a high-grade chewing apparatus duration of chewing of a nut kernel before swallowing on the average makes 14sec and the leftovers are equal to zero (by the method of Christansen), and in absence of 2-3 teeth time of chewing is equal to 23sec, and a part of the kernel remains insufficiently crushed. In cases of the intactand damaged dental system time of chewing soft food differs a little. I.S.Rubinov uses a nut kernel for test instead of 5 g almonds. It enables to judge about functional condition of separate groups of the teeth. Processing of the data received of the kernel chewing is made by S.E.Gelman’s technique.

Graphic methods of studying of themandiblechewing movements.Various diseases of the oral cavity and chewingmuscles impair biomechanics of themandible. In process ofrecoveryof the patient movements of the mandible can be normalized. Normal movements of the mandible, their impairment and dynamics of restorationcan be studied by means of a graphic method.Nowrecord of chewing movements of the mandible can be made by various devices: cymograph, oscillograph, etc.

I.S.Rubinov has been detailed record of chewingmovements of the mandible (masticationagraphy)and value of each of components of the graphic record is deciphered.

Investigation of function of the masticatory muscles.

The function of the masticatory muscles changes not only duringvariousmovings of the mandible but also due to pathologicalconditions of the chewing apparatus: loss of the teeth, diseaseof the joint, change of bite height. Therefore it is desirable to obtain data of the functional condition of chewing muscles bymyotonometryandelectromyographyfor full characteristic of the clinical picture accompanying this or that diseaseof the chewingapparatus.

     The tone of the chewingmusclesis measured by means ofmyotonometry. The devices applied for this purpose refer to as myotonometres. A degree of tension (density) of the muscles we may judge of the supplied force with which a probe of the device is plunged into the selected depth. Arrows of the dial show a degree of muscle tension in grams.

Electromyography.Electromyography is measurementof biopotentials of the muscles in general and on chewing in particular. There arecurrents of actionin themduringcontraction of the muscles. These currents of actioncan be strengthened by special devices and write them down on photographic paper of the oscillograph in the form of a curve. Such methodof research is referred to as myography.

Thermodiagnosis.Detection of the tooth response to temperaturestimuli (warmth or cold) – thermodiagnosis- is one of the simplest methods of investigation of the pulp condition of the tooth. The teethwhich have nochanges in the hard tissues and pulp respond to the thermalfactorabove +50°C, to cold below +10°C. In pulpitis irrigation of the tooth by hot water of +50°C, sometimes below, or applying the tampon moistened with hot waterto the toothcauses sharp, long-termpain, and in deep caries pain is quickly over. The teeth respond to cold and hot substances after preparation, in exposure of the neck, in wedge-shaped defects.

A special device, athermoodontochronometeris used for determination of the tooth response. By means of the device the selected temperatureinfluences a certain site of the tooth. The devicesensor enables to receive temperature from 0 up to +70°C and can smoothly adjust it. The device fixes time of the response.

Diagnosis is one of the most difficult sectionsof clinicalmedicine in general and orthopedic dentisty in particular.Correct diagnosis is possible if resultsof the various investigations confirm reliability of symptoms, andthere is a clear etiology, pathogenesis of the disease,clinical course and pathological anatomy.

The dentist collects the separatefacts (symptoms) in a certain sequence, analyzes them to carry out synthesis of the factscollected.

Having received results of the various investigations confirming reliabilityof symptoms, he compares them with symptoms of knowndiseases and offers a hypothesis) or somehypotheses. There may be several working hypotheses in making a diagnosis. All of them, especially in difficult clinical cases, should be checked up carefully not to make medicalmistakes:diagnosis of one disease instead of another; diagnosis of onediseasewhereas the patient suffers from several diseases, diagnosisof complications of the basic disease without determination of the basicdisease, diagnosis of complications as a basic disease, and the basic one is treated as a complication.

Differentialdiagnosis may help in checking-up of  the hypotheses .

Thus, the diagnosis should be made so that, first,to characterize the cause of the disease, i.e. etiology and pathogenesis, secondly,to give the idea of a pathoanatomical basis of the disease, its localization; thirdly, to specify a degree and characterof functional impairments, fourthly, to specify features of the course andform of the disease.

The case history.The case record (case history) or an out-patient card of the dental patient is the obligatory official andmedicaldocument with data of the examination, the diagnosis,the plan of orthopedic treatment and its performance. All data shouldbe written down consistently and fully so that any other doctor could have a notion about the patient, validity of the chosen method of prosthesis andits outcome. A young doctor starting the practice should  remember that this document, reflecting dynamics of developmentof the disease, a method of treatment and its result simultaneously is the certificateof medical maturity giving evidence of the level of clinical thinking of the doctor, his working abilities.

The case record should be filled so that it was possibleto continue treatment. In other words, other dentist who will continue treatment of the patient, proceeding from the records shouldimagine precisely the clinical picture which is available before treatment, validity of the diagnosis and a technique of treatment.

The case record in some cases can play a role of the legaldocument, therefore records in it should be clear andin sufficient amount.

 

A SCHEME OF FILLING IN THE CASE HISTORY

I. Official data:

   a)Name

   b)Age

   c)Occupation

   d)Address

II. Complaints of the patient (chewing disorders, aesthetics, defect of crowns,mobility, increased abrasion of the teeth, pain inthe temporomandibular joint; pain under basis of the removable denture, pain inthe tooth under artificial crown, etc.)

III. Anamnesis of the disease:

1.From what age the patient started to lose the teeth and what, in what sequence (incisors, canines, premolars, molars).

2.Did the patient note association of pathology of the teeth with working conditions,life, the sustained diseases ( rickets, infectious diseases, bad habits, etc.).

3.The causes why the teeth wereextracted (destruction of the crown,mobility, increased abrasion, osteomyelitis, etc.).

4.Did the patient note development of diseasesof thegastrointestinal tract after loss of the teeth (disorder of taste, appetite, eructation, nausea, vomiting, heavy feeling in the epigastric area before and after meal, pains, etc.).

1.     Whether loss of the teeth was reflected on speech.

2.     Whether the patient restricted intake of foodafter loss of the teeth (substitution of hard food for softer one). Whatside he mainly chews food.

7.How care of the teeth is carried out, at what age and whether it is regular (application of a tooth-brush, powder, paste, cleans the teethonly in the evening or in the morning, before meal, after meal).

8.The patient is prosthesized for the first time or repeatedly. Does he useremovable or fixed denture (during what time, his opinion about the denture.

9.The causes of dissatisfaction with prosthesis (pains, bad fixation of removable dentures, unsatisfactory aesthetics,burning of the mucous membrane of the oral cavity under the denture,nausea, fatigue of the chewing muscles, articulation disorder, impairmentof diction, long adaptation, decubital ulcers, etc.).

10.Estimation of the old denture (aesthetics, occlusion, fixation,conditionof the artificial teeth, of the orthopedic bed tissues,of clasps, the relation to gingival edge, etc.).

11.What general diseases the patient has (anemia,allergy, stomach ulcer, duodenum, diabetes,hypertonicillness, hemiplegia, polyarthritis, bronchial asthma,neuralgiaof the trigeminal nerve, etc.)

12. Presence of bad habits (smoking, the use of alcohol).

13. Medicines the patient constantly or only recently takes.

14. Whether the patient experiences excitement, alarm before forthcomingorthopedictreatment. What causes of excitement are.

15. Whether anesthesia was given in the past in treatment or extraction of the teeth, its efficiency.

16. Peculiarities of the premorbid person (normal subject, withoutdistinct expressiveness of some features, anxious-hypochondriac, with inclination to doubts, demonstrative,hysterical, excitable passive, weak-willed, inspired, withdrawn,unsociable person).

Objective data:

A)           External examination.

1.     Type of the face (conic, inverted conical, square, rounded).

2.     Condition of integuments of the face (colour, turgor, rash, cicatrices, etc.).

3.     Expressiveness of the mental and nasolabial folds(moderately expressed, smoothed out, profound).

4.Character of joining of the lips (lips are closed without pressure,are strained).

5.Corners of the mouth (lowered, are not lowered), there are/there are no perleches.

6.Position of the chin (direct, displaced aside, protrudes, sinks down).

7.Height of the lower third of the face (reduced, increased, unchanged).

B)Examination of the temporomandibular joint (TMJ).

1.     A degree of opening of the mouth (free, limited).

2.     A character of movement of the mandible(smooth, jerky).

3.     Presence of displacement of themandible(to the right, to the left, absent).

4.     Data of palpation of the mandibularheads (movement of headsis smooth, jerky).

5.Data of auscultation (crackle, crepitation, clicking)

C)         Examination of the oral cavity.

1.A general characteristic of the mucous membrane of the oral cavity (colour,moisture, presence of pathological formations: polyps, cicatrices, aphthae, erosions, ulcers, etc.).

2.    Salivation (plentiful, poor, normal).

3.A condition of hygiene of the oral cavity (good, satisfactory,unsatisfactory).

4.Dental formula. A kind of bite (orthognathic, straight line,biprognathic, prognathic, progenic, cross, deep, opened, fixed, unstable, a ratioof the edentulous alveolar processes of the maxilla and mandible).

5.Description of the kind of bite:

   a)Signs of joining concerning all teeth, signs of joining of the anterior teeth,

   b)Signs of joining of the chewing teeth in the buccopalatal direction,

   c)Signs of joining of the teeth in the anteroposterior direction.

6.Inspection of the dentition

   a)The form of the dentitions (ellipse, parabolic, trapezoid, flattened out, etc.),

   b)Position of individual teeth in the dentition

   c)Deformations of the dentition (classification by A.I.Gavrilov, Kennedy).

7.Inspection of the teeth (form, colour, condition of the hard tissues:affection by caries, hypoplasia, fluorosis, presence of fissures, their condition).

8.Examination of the parodont:

   a)A condition of the gums (inflammation, atrophy),

   b)Estimation of the gingival pocket (depth, pyorrhea),

   c)Spread of the process,

   d)Stability of the teeth,

   e)A ratio of the extraalveolar and intraalveolar partsof the teeth.

9.Amount of the antagonistic pairs of the teeth.

1.     The characteristic of the dentition defects (state, localization,form, size).

2.     Condition of the edentulous alveolar process of the maxilla:

   a)Character and degree of atrophy (uniform, nonuniform,big, small, medium),

   b)A kind of the vestibular slope of the maxilla (flat,steep, with a canopy),

   c)Presence of bone ledges on the alveolar process afterextraction of the teeth (localization, extent, depth of undercut, morbidity of the bone ledges on pressure),

   d)The form of the crest of the alveolar process in the anterior and lateral parts (peaked, rectangular, truncated cone,semioval, flattened, a wide crest, a narrow crest),

   e) Presence of the loose crest (localization, size,a degreeof displacement),

   f)Expressiveness of the maxillar tubers (the form of the vestibularand distal surfaces, on the right, on the left).

12.The characteristic of a relief of the hard palate:

   a)The form and height of the hard palate (the high arch, low,medium, wide, narrow),

   b)A condition of the suture of the hard palate (concave, convex, flat),

   c)Palatine torus (form, size, localization),

   d)The form of distal edges of the hard palate (vaulted, flat).

13.The characteristic of the mucous membrane of the orthopedic bed onthe maxilla:

   a)A pliability of the mucous membrane of the hard palate,

   b)Expressiveness of buffer zones,

   c)Expressiveness of transversal palatine folds in the anterior partof the hard palate

   d)Expressiveness of the palatine blind apertures, their localization (onthe line “A”, ahead of the line “A”, behind the line “A”),

   e)Incisive papilla (size, pliability),

   f)The location of the transitive fold in relation tothe alveolarprocess (at the basis, at the level of slope, at the top),

   g)A degree of expressiveness, the form and place of the bridle attachment of the upper lip, anterior and lateral buccal-alveolar streaks of the mucous membrane (at the basis, to the slope of the maxillar tuber,upper tuber, to aponeurosis of the muscle of the soft palate).

14.The condition of the bone basis of the orthopedic floor of the mandible:

   a)Character and degree of atrophy of the alveolar process (uniform, non-uniform, big, small, medium),

   b)The size, form and localization of exostoses,

   c)Presence of mental torus (size, form),

   d)Expressiveness of the internal slanting lines, their form (sharp,pointed, rounded), morbidity on pressure,

   e)Presence of bone formations on the alveolar process afterremoval of the teeth (localization, form, size,sensitivityto pressure),

   f) The form of the crest of the alveolar process in the anterior and lateralparts of the mandible(peaked, rectangular, trunkated cone, semi-oval, flattened, wide crest),

   g) Presence of the loose crest on the mandible (localization, size, a degree of displacement).

15.The characteristic of the mucous membrane of the orthopedic bed on the mandible:

   a)The location of the transitive fold in relation tothe alveolar process (at the basis, at the level of slope, at the top),

   b)A degree of expressiveness, the form and place of the bridle attachment of the lower lip, tongue, anterior and lateral buccal-alveolarstreaks of the mucous membrane (at the basis, to the slope, to the topof the alveolar process),

    c)  Presence of folds of the mucous membrane of the alveolar process (the arrangement, direction, get smoothed out, do not get smoothed out),

   d)Mucous tubercles (the form, size, mobility,consistency, tenderness on palpation).

1.     The size and form of hypoglossal space (on the right, on the left).

2.     The size and form of the hypoglossal space in the anterior partof the mandible (big, small, in the form of fissure,of the triangularform, trapezoid).

3.     Submaxillary salivary glands (presence, their position in movements of the tongue: protrude over the crest of the alveolar process, do not protrude).

4.     The size and tonus of the tongue (enlarged, not enlarged, the tonus is moderate, increased).

5.     Tonus of the muscles of the floor of the oral cavity, cheeks and lips moderate, increased, lowered).

Data of special methods of examination:

1.The radiological characteristic of the teeth and periodontal tissues

(a condition of hard tissues of the crown and root, the size andpeculiarities of the tooth cavity, root canals, width and characteristic ofthe periodontal fissures, a condition of the compact plate, a wall of the alveolus and spongy substance of the alveolar process,presenceof foci of chronic inflammation, etc.)

1.     Data of radiological examination of the TMJ.

2.     Data of tomography and cephalometry.

3.     Data of studying diagnostic models of the jaws.

The diagnosis and differential diagnosis.

     The diagnosis is made on the basis of data of clinical examination of the patient, which should consist of the basic and accompanying one.

     1. The basic disease and its complications:

a) What basic disease has inducedthe patientto refer toorthopedic clinic;

b) Complications and impairments whichare associated pathogeneticallywith the basic disease.

 2.Concomitant diseases which are treated by dentists of other sections of dentistry. Differentialdiagnosisis made if necessary.

 3.In the diagnosis “Partial loss of the teeth” it is necessary to specify a kind of dental defectby Keneddy, and “Full loss of teeth”- typeof the edentulous jaw by I.M.Oksman.

A plan of preparation of the oral cavity to prosthesis:

1. General sanation measures (removal of dental deposit,treatmentof the teeth, removal of the roots and teeth with mobility of III degree, treatmentof diseases of the mucous membrane of the oral cavity, etc.).

2. Special preparation of the oral cavity (depulpated teeth,eliminationof occlusion impairments, orthodonticpreparation, alveolotomy, excision of cicatricies, transfer of the placeof bridle attachment, streaks of the mucous membrane, deepening of the thresholdof the mouth, floor of the oral cavity, etc.).

A plan of the orthopedic course.

Specify what kind of prosthesis (immediate, nearest,remote). Substantiate a choice of the denture construction.

A diary of orthopedic treatment.

All references of the patient are written down with the indication of date andthe detailed description of the given clinical procedures. In repeatedreferences of the patient after application of the denture the complaints,given objective investigation, character of the rendered aid and features of the patient’s adaptation to a denture are described. Make assessment of the nearestresults of prosthesis (quality of the denture, functional properties, a condition and reaction of orthopedic bed tissues, amountof corrections, a response of the patient, etc.).

Epicrisis and prognosis of orthopedic treatment.

First, middle, last name, age and complaints of the patient on the dayof reference to clinic are written down, the diagnosis made, the beginning and termination of treatment, a kind of prosthesis and a denture construction.

A condition of the patient as a result of the treatment given andprognosis are described.

As most edentulous patients are elderly, the examination must be carried out not only with regard to the condition of the oral cavity, but in relation to their general health. Howev­er, sometimes dentists with less clinical experience may reach for an impression tray and start making the impression as soon as the patient sits in the dental chair without a definite treatment plan. If we want to make a successful denture, we must first conduct a thorough extra and intraoral examination of the mouth including the condition of the existing denture, denture-supporting areas, the condition of the temporoman­dibular joint and the appearance. The intraoral examination, in particular, should be done not only by glancing at, but also by closely observing and palpating the alveolar ridge. For example, if the bone resorption is severe, the alveolar ridges are flattened and moreover the mylohyoid ridge is shar­pened on the lingual side and the covering mucosa is very thin. These points can be determined by palpating the areas. If such areas are found, we should think about using relief and a soft lining material.

 

 

First we must look at, carefully observe and then palpate the alveolar ridge.

1. Surgical treatment

Certain oral conditions require surgical treatment to im­prove the environment for denture construction. If there is redness or an ulcer over the area where the denture impinges, we can eliminate it by adjusting the denture. If there is wide­spread inflammation over the denture-bearing mucosa, it will recover quickly by removal of the denture for 2-3 days or by use of a tissue conditioning material. However, surgical treat­ment is still necessary for the denture-bearing tissues of some edentulous patients. Other cases may only require rehabilita­tion by prosthodontic means, but surgical modification is sometimes advantageous to improve the retention and stability of the denture.

The wearing of an ill-fitting denture for a long time causes

 In the case of severe alveolar bone resorp­tion, palpation is inevitable. If spiny ridges and thin covering mucosa are felt, we have to think about re­lief and soft liners.

repeated irritation to the mucosa during chewing, and conse­quently fibrous growth of the tissue will occur as a defense re­sponse. Soft tissue hyperplasia occurs under or around a com­plete denture and is referred to as so-called flabby gums or denture fibroma.

As flabby gums, which are seen in the anterior residual ridge of the maxilla and mandible, are highly compressible and displaceable, it is difficult to make an impression in the usual way. When this is not excessive, a good result may be possible by proper prosthodontic treat­ment, but a severe case may need surgical intervention. Elder­ly people may have difficulty in cleaning their dentures and mouth sufficiently and thus the prolonged wearing of an ill-fit­ting denture might lead to a stomatitis like papillomatosis. In mild cases, healing may occur after resting the tissues which can be achieved by removal of the dentures and improvement of oral hygiene.

In certain cases, it is impossible to make impressions without any surgical treatment. shows a so-called denture fibroma. A massive roll of hyperplastic tissue which extends from the anterior residual ridge to the oral vestibule in the maxilla is referred to as epulis fissuratum and needs to be excised surgically before making a new denture. However, when we eliminate a wide area as in this case, if we try to eliminate all the pathological tissue, it may leave a scar in the area which is essential for denture retention and consequently, the subsequent prosthodontic treatment will become harder. So, we must decide the area of elimination by careful treatment planning which will be favorable for further procedures.

Some cases have large undercuts in the region of the tuberosity or anterior residual ridges. If the flanges in these areas are extended deep into the sulci for the peripheral seal, these undercuts might interfere with denture insertion and removal. When there is an undercut on only one side, the insertion of the denture is possible by rotating it into position and this undercut may even enhance denture retention. However, when there are undercuts on both sides, surgical elimination or easing of the denture border must be per­formed. In the case of surgical treatment, it is important that the amount of bone removed should be as minimal as possi­ble because many undercuts are covered by compressible mu­cosa and are not as large as we expect.

The other indications for pre-prosthetic surgery are a pen­dulous maxillary tuberosity, prominent maxillary torus and mandibular tori, excessive undercuts, spiny ridges, etc. In cases with severe alveolar bone resorption where the denture-supporting tissues are limited, surgical procedures such as ves

tibuloplasty or ridge augmentation may be carried out.

 

Although surgical treatments may be necessary for a good result, for elderly patients, the physical and mental trauma might effect their general health and therefore surgical treat­ment is sometimes better avoided. Even if they can withstand the surgery, in advanced age, the healing processes are de­layed and post-operative conditions of the oral cavity may be more severe.

In any case, the indiscriminate use of surgery just for pros-thodontic convenience should be avoided. Surgery should be avoided if at all possible and the denture should be improved by various prosthodontic techniques such as varying the im­pression technique and providing appropriate relief over the affected area.

 2. Correcting the occlusion

 It is important to examine whether any problems of the temporomandibular joint may be present and also the occlu­sion of the existing dentures. A patient wearing ill-fitting de­ntures for a long time tends to occlude in a position far away from the centric occlusal position as a result of the functional adaptation in which one masticates in a position comfortable to him/herself. This is the so-called “habitual bite” and will cause a decrease in masticatory efficiency and moreover lead to mandibular dysfunction.

The habitual eccentric occlusion should be treated before making new dentures. However, because the muscles of mas­tication have learned the habitual eccentric jaw position for a long time, sudden correction is not easy. Generally, the habi-

 

The flattened occlusal surface eliminates the intercuspation of the artificial teeth in the habitual eccentric jaw position and therefore can relieve the stiffness in the muscles and joints. Without the limitation of the cusps, the jaw can gradually return to its centric occlusal position

tual eccentric occlusion may be corrected by wearing treat­ment dentures for a relatively long period of time. The patient will also be satisfied with the recovery of the occlusion by treatment dentures and further recording of the maxilloman-dibular relationship will be smooth and accurate.

3. Flow of saliva

Through aging, salivary flow decreases and its contents change. As saliva enhances denture retention by intervening between the denture and the mucosa, a patient with scanty saliva will have poor denture retention. Also in a dry oral cavity, the mucosa lying beneath the denture base may be easily-traumatized and therefore the impression surface of the denture must be polished more smoothly. The diminution in salivary flow will not moisten the oral mucosa and will interfere with the functions of mastication, swallowing and phonetics. In some cases, the use of artificial saliva or medications promoting salivary secretion should be recommended.

4. Patient’s requests and desires

There is one more important step in the examination. At the patient’s first visit to the clinic, we must quickly and pre­cisely gather what (s)he requests mostly from his/her com­plaints about the existing dentures. Their requests might be confined to mastication, esthetics or phonetics.

It once happened that a patient repeatedly came to my clinic and complained of pain, even though the dentures were thought to be perfect and no ulcers or inflammation could be found on the mucosa. Finally, it was proved that the patient’s complaint was not pain, but the appearance of the arrange­ment of the anterior teeth. If the patient is satisfied with the appearance, (s)he would definitely wear the denture even with a little bit of pain or a poor fit. Complaints related to esthetics are difficult to find as the patient is sometimes too embarrassed to talk about them and sometimes it is even an under­lying complaint which the patient is not conscious of. There­fore a careful examination which involves gathering the patient’s requests is recommended.

In any case, the denture is a piece of work constructed by the dentist, but the patient becomes its owner after insertion. We can be no more proud of, or satisfied with, our dentures as wonderful products by ourselves alone. It is important to make the denture suit the patient so that the new dentures can truly become his/her own. For this, we must make a denture that contains the patient’s “heart”. The denture should

never be a “stranger” to the patient. In other words, only when the patient’s requests have been included in the denture, will it then become his/her own denture. The complaints of the patient are often unclear, misunderstood and confused; however, I believe that they have expressed their honest feelings and I have therefore tried to listen to their words carefully

Making the impressions

In a favorable denture case where alveolar bone resorption is minimal and the cross section of the alveolar ridge resem­bles a U-shaped outline, border molding during impression making is easy. A proper impression is made possible just by reproducing the contour of the sulcus onto the impression as it is seen. However, in an unfavorable case with severe alveolar bone resorption due to severe periodontitis or prolonged wearing of an ill-fitting denture, some dentists might be puzzled how to take the impression and how to extend the denture borders correctly. In these unfavorable cases, if the denture border is placed at the junction of immovable ging­ivae and movable mucosa only by passive hand manipulations, it will result in the so-called cord-like denture, leading to poor denture retention, especially in the mandible.

As is generally known, the wider the denture base area, the better the denture retention will be. Therefore the impression making — not impression taking — should be performed actively according to our objectives so that the denture base area can be enlarged as much as possible. However, it is not appropriate to extend the denture border at random. The denture border should be appropriately extended in the areas where it is possible to extend it and the border should be limited where extention is not required. In order to perform this, initially it is important to understand what form the denture base should take and then the impression making is carried out in accordance with that mental image.

When the condition of the alveolar ridge is unfavorable, some dentists may say, “Only after impression taking can the situation of the alveolar ridge be grasped or the denture border can be shaped”. HoweveT, if we are not convinced of the contour of the impression before impression making, we will never obtain a successful denture. It is like admitting defeat before beginning the battle.

1. Landmarks for the mandibular impression

Buccal flange area

In Ihc poor situation where the ridges are flat and the mov­able mucosa reaches up to the crest of the alveolar ridges, the sole area of resistance to occlusal forces would be the buccal shelf which is situated on the buccal side of the area of the posterior teeth. The buccal shelf is covered with dense cortical bone and is also a wide area lying perpendicular to the direc­tion of the occlusal forces. Therefore, it is an appropriate area for denture support. Thus, in severely resorbed ridges, there must be no doubt in using the buccal shelf as the denture support. The buccal shelf must be recorded during the impression procedure, otherwise a satisfactory impression will not result.

Outside the buccal shelf, a bony ridge runs anteroposterior-ly which is called the external oblique ridge and is used as a landmark for the denture border. The denture border can be extended 1-2 mm beyond the external oblique ridge and therefore the ridge must be recorded by making the imprcss-ion.

 

However, if the denture border is extended beyond the ex­ternal oblique ridge, the denture base will be widened over the buccinator muscle attachment and thus located on the buccinator muscle fibers.

On the buccal shelf, the buccinator muscle fibers run close to the bone, and are thin, tendinous and thus inactive. In addition, the lower muscle bundles of the buccinator are not tense and slacken laterally from the external oblique ridge

If the demure border is extended beyond the external oblique ridge, the denture base will cov­er the buccinator muscle fibers. However, since the lower muscle bundle of the buccinator is loose and inactive, it will not dislodge the denture.

The fibers of the buccinator run anteropos­terior, so that the force dislodging the denture dur­ing mastication.

If the denture border is underextended in the buccal shelf area, a convex buccal flange will not be possible, so it will not be able to occupy the buc­cal pouch. A space will occur between the denture border and the lower muscle bundle of the buccina­tor, resulting in food accumulation.

Therefore, the force dislodging the denture during mastication is small and thus it is possible to extend the denture border into this area.

 

If the denture border is underextended in this area, it is dif­ficult to mould the convex buccal flange correctlyf, leading to food accumulation in the buccal sulcus and under the denture base.

 

Mylohyoid ridge area

If the denture border is short of the mylohyoid ridge, it will dig into the residual ridge and cause pain.

The border is shortened to remove this pain, but shortly after, the shortened border again impinges upon the residual ridge. Finally this re­petition will make the denture into a cord-like denture which has poorer retention and stability.

 

.

Border molding of the mylohyoid ridge area should be per­formed to cover the ridge 4-6 mm beyond it. At the insertion appointment, the impression surface of the denture on the mylohyoid ridge is relieved so that pain during mastication will be diminished.

In addition, when the lingual denture border is extended properly as mentioned above, the lingual polished surface can be shaped into a concave form(the concave shelf, which is important for the retention and stability of the de-nture.

In a serious case where the residual ridge is poor, the mem­branous attachment of the floor of the mouth appears high in the mylohyoid area. This appearance may lead dentists to assume that the muscles are strained parallel to the floor of

A denture border short of the mylohyoid ridge digs into the residual ridge and causes pain. If shortened, the denture border will impinge again upon the ridge.

the mouth during contraction which might cause pain or de­nture dislodgment and therefore the denture borders tend to be mistakenly shortened. However, as the muscle fibers run anteroinferiorly even during maximum muscle contraction, it is possible to extend the denture border beyond the mylohy­oid ridge to which the mylohyoid muscle attaches. Moreover, in the case of the elderly, the contraction of the mylohyoid muscle is not so strong. The muscle tension can be evaluated by palpating the floor of the mouth with a finger or a mouth mirror.

When making an impression of this region, some think that the movement of the mylohyoid muscle would be recorded by moving the tip of tongue toward the opposite side. However, tongue movement is due to the action of the gcnioglossus musclc. The mylohyoid muscle contracts during swallowing. By this tongue movement, instead of the move­ment of the mylohyoid muscle, the movement of the floor of the mouth which might be strained by the tongue will be re­corded. This movement of the tongue can be considered to be exaggerated.

As exaggerated tongue movements during impression making will be the cause of underextended borders, excessive movements should be avoided. If the tongue is protruded over the dental arch, the lingual sulcus will become shallow and an extremely shortened border will be obtained. During ordinary functions like mastication, the tongue is never protruded out­side the dental arch, like a child’s playful gesture of sticking out his/her tongue. If protruded, it might be bitten during mastication. A functional situation is, in other words, not a state of exaggerated movements. Furthermore, even if the dentist understands the tongue movements, during impression taking, it is impossible to expect an elderly patient to follow such a complicated instruction. Impression making should be performed only by the dentist him/herself. U should never be a task requiring assistance from the patient.

As the denture is used in a closed mouth, the tongue should not be moved around too much during impression making. The author never invites tongue movement during impression making. The patient is asked only to relax the tongue comfortably. The impression is then made 4-6 mm below the landmark, the mylohyoid ridge, and thus the extent of the denture border is decided at the mylohyoid ridge area. Even though the case may be favorable for more inferior extension of the border, the border is limited only to this length by trimming the extended border. Of course, denture reten­tion and stability may be better with the lengthened border.

However, some patients will complain of tightness at the base of the tongue in lengthened cases. Therefore the denture bor­der should be extended only as far as necessary.

Retromolar pad area

The denture must cover more than half of the retromolar pad. Histologically, the retromolar pad is composed of a firm fibrous connective tissue papilla in its anterior half and soft tissue containing molar glands in the posterior half. These two parts are named separately as the anterior “pear-shaped pad” and the posterior “retromolar pad”.¹‘²‘ However, in edentu­lous cases, it is hard to distinguish them with the naked eye and thus clinically the two parts should be regarded together as the retromolar pad.

The posterior peripheral seal can be obtained by placing the denture border over this resilient glandular tissue. Anywhere is possible on the glandular tissue, but if the den­ture border is placed too far posteriorly, some patients will complain of tightness at the base of the tongue and therefore it is best to cover 2/3 of the retromolar pad.

As the temporalis muscle fibers attach to the distal portion of the retromolar pad, stimulation from this muscle prevents the pad from resorbing. So, the retromolar pad is also used as a landmark for orientation of the occlusal plane. There­fore the retromolar pad must be included in the impres­sion.

Even though the mandibular molar region is thought to be the most difficult area for impression making, the outline of the denture base can be determined easily and automatically by using these indexes. It is just necessary to connect the in­dex lines, namely lines placed 1 mm beyond the external obli­que ridge, 2/3 of the way from the anterior border of the re­tromolar pad and 4 to 6 mm below the mylohyoid ridge.

However, pain may occur on the buccal side of the re­tromolar pad region during mastication even though the de­nture is designed in the above mentioned ways. This is due to the masseter muscle, a strong elevator, which is lateral to the retromolar pad and covers the buccinator muscle. When the masseter muscle contracts, its enlargement presses the denture border with the cramped buccinator muscle. As the denture occludes, it caot move during function of the elevators. So, when the distobuccal border of the denture base is extended into the functioning area of the masseter muscle, the mucosa will be pressed against the denture base leading to pain .

In order to avoid such a situation, the movement of the

The masseter muscle attaches at the ex­ternal side of the retromolar pad and covers the buc­cinator. It indirectly presses the denture border through the cramped buccinator during function.

masseter muscle is recorded in the impression by creating its reactive contraction through pushing the tray during the bor­der molding procedure. The tension of the masseter muscle will make a concavity in the distobuccal outline of the impression. Another way is to reduce the ovcrlengthened border through observing the redness or displacement of the denture after insertion of the new denture made by connecting the index lines. This method is easier for those who are not familiar with the previous one.

Retromylohyoid fossa

The posterior border of the lingual flange can be the curve obtained by connecting the index lines placed 4-6 mm lower than the mylohyoid ridge and on the retromolar pad. However, it is generally assumed that the denture border lengthened posteroinferiorly into the retromylohyoid fossa can promote retention and stability of the denture. The author has occasionally lengthened the border for those cases with severe bone resorption. However, it has caused the complaint of tightness at the base of the tongue. Therefore retention and stability have been obtained by other mcansf rather than a lengthened border in the majority of cases.

Actually it is very difficult to make a definitive border, namely to make an appropriate impression, in this area. If the denture border is lengthened inappropriately, this will be the worst possible situation and will result in the opposite effect of the aim such as the dislodgment of the denture or an ulcer occurring along the overextended border. The posterior bor­der established by connecting the index lines, as mentioned before, is just enough in cases where retention and stability can be obtained by other means. In almost all cases, the bor­der obtained by this method will be usable. Simplicity is best.

Although the above method is recommended, one may make use of the retromylohyoid fossa.

The space distal to the mylohyoid muscle is referred to as the retromylohyoid fossa. It is bounded by the mylohyoid muscle anteriorly, the retromolar pad laterally, the superior constrictor muscle posterolaterally, the palatoglossus muscle posteromedially, and the tongue medially. There is no struc­ture and so it is possible to lengthen the denture border into this space. During border molding, the border in this area is pushed into the retromylohyoid fossa by the strong intrinsic and extrinsic tongue muscles, and thus it will show the so-cal­led S-curve as viewed from the impression surface. At this time, the posterior limit of the lingual border is de­fined by the palatoglossus muscle and the lingual slip of the superior constrictor muscle. This is called the retromylohyoid curtain. When the tongue is protruded, the curtain also moves anteriorly. In some cases, the retromylohyoid fos­sa becomes greatly shortened and it seems impossible to ex­tend the denture border. The extension of the denture border can be determined by examining the tightness of the fossa with a mouth mirror when the patient is instructed to make moderate tongue movements such as touching the maxillary anterior ridge with the tip of the tongue. Usually the space is wideT than expcctcd.

By extending the denture flange into this region, a peripheral seal can be obtained continuously from the re-tromolar pad region to the anterior lingual sulcus. In addition, this extended lingual flange can be shaped accordingly for guiding tongue placement onto the polished surface of the lingual flange. Moreover, the projected posterior border will literally serve as a flange(the projecting edge of a train wheel) by physical means, leading to an improved denture.

Sublingual gland area

The sublingual gland lies above the mylohyoid muscle. The gland is raised when the mylohyoid muscle contracts during swallowing.

Position of the sublingual gland. It lies above the mylohyoid muscle and is raised by the contracted mylohyoid during swallow­ing.

The position of the mucosa of the floor of the mouth may be recorded higher through impression making by excessively moving the tip of the tongue. However, the lingual flange extension is decreased and a space is created between the denture border and the mucosa of the floor of the mouth whilst the mylohyoid muscle is at rest, leading to impairment of the peripheral seal.

Similar to impression making in the mylohyoid ridge area, the patient is never instructed to perform any movements of the tongue, but asked only to relax the tongue comfortably. The mouth is nearly closed and the tongue lies on the floor of the mouth completely. This is the “impression position” of the tonguef.

Through border molding, the depth of the lingual vestibule is recorded in this situation and this will in turn be used as the length of the lingual flange in the sublingual gland area, so that the lingual border seal can be established effectively.

Is this length all right when the sublingual gland is raised by the contracted mylohyoid muscle or not?

The lower denture will not be lifted up, even though the sublingual gland is raised, as the upper and lower teeth are in contact when swallowing. On the other hand, the sublingual gland serves as a cushion due to its soft and resilient nature and therefore it will neither lift the denture nor will its cover­ing mucosa be traumatized by the denture.

This length is quite enough for normal functional movements.

Some dentists are not satisfied unless tongue movements are used to record the movement of the floor of the mouth. The movements should be carried out by pressing the anterior portion of the tongue with the forefinger of the operator’s other hand during impression making. Only such an degree of tongue movement is recommended. Exaggerated tongue movements will cause an underextended denture border.

Classification of atrophy stages

Based on the classification system of Nakamato (1968) six separate segments of the jaw were defined asdepicted in

Stage 1 describes the physiological state of preextraction at which the tooth is still in the alveolar socket or the

tooth is lost post mortem.

Stage 2 is assigned to tooth loss immediately before death. There are slight osseous reactions of new bone formation within the alveolus. The alveolus is still in a good condition and the edges

might be sharpened.

In stage 3 the alveolus is completely refilled with newly formed bone. The shape of the original alveolus is no 5 longer identifiable and the top of the alveolar process finally becomes well-rounded due to first signs of resorption. However, there is no notable reduction in height.

In stage 4 the shape of the alveolar crest alters into a thin and sharp knife-edge; the body of the jaw is still adequate in height and width.

Stage 5: Further resorption leads to a low well-rounded ridge which is flat but already reduced in height and width; the alveolar process is lost.

Stage 6: Continuing excessive atrophy of the residual crest results in a depressed bone level, where even the basal bone shows signs of reduction.

2. Exposed trabecular bone at the top of the residual ridge

Atwood (1971) and Pietrokovski (1975) stated that in many individuals the cortical layer cannot close over the former alveolus and adjacent areas sufficiently due to degenerative and resorptive alterations of the alveolar crest. Accordingly, the residual crest exhibits trabecular bone, extending over the whole length of an edentulous ridge.

Stage I describes the situation after tooth loss in which the alveolus is totally closed and the crest completely covered by cortical bone.

In stage II, the cortical layer of the alveolar crest is not closed, but discontinuous so that an area of exposed trabecular bone with a width of up to 2mm is identifiable.

In stage III, the cortical layer of the crest is interrupted by even larger areas of exposed trabecular bone of more than 2mm in width.

3. Bony defects in the region of the former alveolus

Due to poor or incomplete repair of the alveolus after tooth loss, bony defects such as trabecular spots and macroscopic perforations (Solar et al., 1998) might be observed on the crest of the residual ridge (Nakamato, 1968; Pietrokovski et al., 2007). As opposed to exposed trabecular bone, the occurrence of this feature is thought to be restricted to the area of the former alveolus (Neufeld, 1958; Lammie, 1960). However, Nakamoto (1968) doubted this limited extension of such defects since he could not detect a relation between the area of former alveolar sockets and the location of defects. To scrutinise this discrepancy and to check whether a discrimination of exposed trabecular bone and defects is expedient and useful, both features are separately assessed in this present study.

In stage I, no defects are present. Stage II characterises a residual alveolar crest with small defects. The cortical layer encircles little trabecular inclusions of e.g. flame-like or channel-like shape.

In stage III, the observed irregularities at the cortical layer are increased in size.

4. Concave depression of the alveolar crest

In consequence of the loss of several adjacent teeth, the bone tissue in this edentulous space often breaks down.

The wound area in this edentulous part of the jaw is too large, so that bone is not able to regenerate up to the height of the former alveolar crest resulting in a depressed level of the residual ridge. Towards the adjacent tooth (or teeth, if existent) the bone level maintains the original height of the alveolar process. So-called concave depressions can be observed at the distal end of the dentate arch (Pietrokovski, 1975) as well as in an edentulous space between remaining teeth.

A segment is classified as stage I if there is no concavity observed.

Stage II describes an edentulous ridge portion with a concave depression looking like a recess in the residual ridge.

5. Exposed mandibular canal

Excessive resorption of the mandibular residual ridge can lead to a reduction of the alveolar crest towards the mandibular canal (Ulm et al., 1989). In the final stage of resorption, the canal containing the mandibular.

 

5. Exposed mandibular canal

Excessive resorption of the mandibular residual ridge can lead to a reduction of the alveolar crest towards the mandibular canal (Ulm et al., 1989). In the final stage of resorption, the canal containing the mandibular nerve and blood vessels might even lie directly on the surface, solely covered with gingiva in the living individual. In this case, the canal is opened and its borders are well-defined.

In stage I, the mandibular canal is still completely covered with bone. In stage II, the mandibular canal is exposed.

 Classification system of six atrophy stages in the maxilla (A) and the mandible (B)

according to Atwood (1963) and Cawood and Howell (1988). Atrophy stage 1: preextraction, stage 2: postextraction, stage 3: high well-rounded ridge, stage 4: knife-edge shaped ridge, stage 5: low well-rounded ridge, stage 6: depressed bone level.

 

 

Changes in the Jaw Bones, Teeth and Face after Tooth Loss

The loss of teeth create many problems from the dissolving away of bone structure, loss of support for the face giving an increased appearance of age and wrinkles, damage to the remaining teeth that must still bear the full stresses of chewing. Once enough teeth are missing then food choices and nutritional changes begin to cause medical problems and affect your general well being.

Loss of a Single Tooth

Even after the loss of one tooth, the jaw bone irreversibly changes if an implant does not replace the tooth.

Without chewing pressure to stimulate the bone it begins to dissolve away immediately after extraction and continues forever unless an implant is placed. If left long enough, bone grafting is necessary before an implant can be used. The last picture above shows when the bone loss has reached the severe state.

Loss of an Entire Jaw of Teeth

Below a healthy jaw is compared to one where all of the teeth have been removed and deterioration of the jaw occurs. The deterioration is described beneath the very last picture in the series

As the bone shrinks, vital structures (such as the nerve) become exposed. The denture then pushes on this nerve making the denture even more painful to wear.

Facial Cosmetic Problems after Tooth Loss

The deterioration of the jaw bones effects the appearance of how the face “drapes” over the bone. This makes you look far older then your natural age and adds more non-age related wrinkles then mother nature intended for you.

Facial Shrinkage

Facial sagging, premature ageing, and loss of function are the results of the shrinkage in the upper and lower jaw bones.

Tooth Drifting and Destruction to the Remaining Teeth

When all teeth are present and touching throughout the mouth the teeth support each other much like the bricks in a roman archway.

When

When teeth are missing, the opposite teeth have no “counter acting force” and will erupt upward into the mouth.

When no back teeth are touching the stress is now placed on the front teeth, this ‘overloads’ them and forces them to move forward and outward.

When back molars are missing the damage is even more serious.

The back chewing teeth begin to erupt down into the empty spaces where the lower molar teeth are missing.

The back chewing teeth drop even further down into the lower missing teeth spaces

The chewing forces have shifted to the front teeth and due to overloaded stress the front teeth begin to flare and fan apart creating spaces

The fanning and spaces get worse over time

This fanning eventually leads to looseness and gum disease and the loss of the front

This example is an example of the “fanning out” and opening of front spaces due to the missing back teeth. These teeth are no longer savable.

This shows severe over eruption of an upper molar with most of this tooth’s roots now being out of the bone structure. The tooth will become loose and fall out during chewing and usually at an inconvenient time.

Even a single missing teeth can lead to drift (this is just like taking a brick out of an arch way and seeing the arch collapse). That one missing tooth can set you up for a “domino effect” of losing teeth for the rest of your life.

The next molar beings to drift forward