THE PBENOMENON COMPLETE DENTURE
FUNCTION IN PROSTHODONTICS
CLINICAL APPLICATIONS OF CONCEPTS OF FUNCTIONAL ANATOMY AND SPEECH SCIENCE TO COMPLETE DENTURE PROSTHODONTICS Part VI. The Diagnostic Phase* ALEXANDER L. MARTONE, D.D.S., M.Sc.” ii
indicate that 50 per cent of America’s senior citizens, 60 years of age and older, wear or should wear complete dentures. These studies further indicate that the proportion of the population 65 years of age and older increased 70 per cent from 1930 to 1960 and that further increases may be expected. Unfortunately, loss of teeth is not limited to the geriatric years, and many young patients are also candidates for complete dentures because of neglect or accident. With the growing numbers of edentulous patients, there is increasing responsibility placed on dentists to provide prosthodontic treatment which will not only replace missing structures and preserve remaining tissues but which will also maintain functional activities that take place in the oral region. By improvement of the quality of prosthetic dentistry, the physical and mental trauma associated with edentulousness can be lessened. The remaining articles of this series will suggest clinical applications of functional anatomy and speech science to the diagnostic, recording, esthetic, and postinsertion phases of complete denture construction. URRENT
Prosthodontic diagnosis requires more thorough patient evaluation than diagnosis for any other phase of dental treatment. Mere recording of statistical information as to the patient’s age, history, sex, and physical characteristics will not suffice. Effective prosthodontic treatment must be based on the evaluation of the total entity of the patient. *Part
I, J. PROS. DEN. 11:1009-1018, 1961; Part II, J. PROS. DEN. 12:4-27, 1962; Part III, f. PROS. 1962; Part IV, J. PROS. DEN. 12:409-419, 1962; Part V, J. PROS. DEN. 12:629-636,
DEN. 12:206-219, 1962. **Associate,
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Time spent in the diagnostic phase enables the dentist to employ “postoperative vision” while he is planning the treatment. This approach can minimize failures. The development of postoperative vision preoperatively is dependent upon the use of diagnostic techniques which provide the necessary knowledge for a realistic evaluation of the patient’s prosthodontic possibilities and limitations. This is the basis for a sound concept of prosthodontic diagnosis, and it is far different from the simple recognition that the patient is edentulous and, therefore, complete dentures are required. Diagnosis begins when the dentist first views his patient. At this moment, he receives immediate mental impressions relative to the patient’s general physical appearance, age, gait, posture, coloring, facial contours, etc. These are observations based on external signs and symptoms revealed in surface anatomy. SURFACE
Surface markings or topography in relation to the underlying musculature responsible for them have been discussed. 4 Changes in surface anatomy which are caused by loss of support from natural tissues or their artificial substitutes are evident when an adequate diagnosis is made. External Evidences of Structural Losses.-One of the objectives of prosthodontic treatment is to bring the lower third of the face into harmony with the upper two-thirds, which suffers comparatively little of the structural loss incurred in normal aging. Some of the external evidences of loss of supporting structures are sunken cheeks, flattened lips, decrease in the width of the vermilion border of the lips, increased depth of folds and grooves in the face, and a decrease of occlusal vertical dimension, producing changes in facial proportions and bringing the nose closer to the chin. However, lack of support may not always be the entire cause of some of the signs and symptoms apparent in surface anatomy. Inherited tendencies can exert strong influences on surface markings, such as folds and grooves or lip contours. It is important to determine whether surface markings are the result of supportive loss or are inherited characteristics of the individual. This will affect the prosthodontic treatment because any attempt to provide support artificially where there has been no loss of support will result in eradication of natural contours which are characteristic of the patient. Photographs of the patient when he was young and had natural teeth are aids in making this evaluation. Opportunities to observe relatives of the patient will sometimes furnish clues to family tendencies. Losses of elasticity of the skin and muscular tonicity are also apparent in studying skin texture and tone and result from loss of supporting structures. External Evidences of Temperament and Tension.-In general, the direction of the lines of the face can be taken as indicative of the individual’s emotional makeup or temperament. A person with a happy disposition, accustomed to smiling and laughing, has facial lines with the upward cast characteristic of mirth. Conversely, the person with a dour personality is likely to have facial lines with a downward slant associated with sorrow or grief. Observation of these facial markings in the initial diagnosis provides a clue to the temperament of the pa-
tient and suggests problems which may be encountered in determining the proper amount of support by the denture for the facial structures in order to preserve or minimize certain facial lines. The lines produced by facial expressions of grief or discontent, which have been and will continue to be characteristic of a person with an unhappy disposition, present a different prosthodontic problem from that encountered when a down in the mouth expression is the result of supportive loss of natural tissues that has not been restored by dentures. In the first instance, prosthodontic efforts designed to overcome evidences of a grim temperament can be doomed to failure. Even the most successful dentures cannot change a Scrooge into a Pollyanna. Hnwever, there is a favorable prognosis for prosthodontic correction of a downward slant of the mouth which is the result of lack of support. Symptoms of stresses or tensions are frequently apparent in the surface anatomy of the face and neck. These symptoms include taut lines about the mouth, tightly compressed lips, teeth held almost continuously in contact with a resultant loss of vertical dimension of occlusion, and strained musculature in the neck region. Such tensions may result from ill-fitting dentures. Further functional analysis and clinical examination should seek to determine which tensions ma! have den.tal origin. Other Indications From Surface Anatonay.--Surface anatomy may indicate the type and amount of muscular development of the patient. This involves the muscle attachments within the oral cavity, the strength and amount of tongue activity, and the dislodging forces that may be exerted on dentures by the muscles of facial expression and craniomandibular muscles. The eyes are frequently the most expressive features of the face. They may gain in attractiveness in the aging process, while the mouth may become less attractive. Although distant from the mouth, the eyes do have significance in prosthodontic diagnosis and treatment. Asymmetry of the face may be apparent in the eyes, since their shape contributes to the general contour of the face. Any asymmetry of the eyes observed in diagnosis should be noted so that necessary allowances can be made when the pupils of the eyes are used as reference points in building occlusion rims or in positioning teeth. The degree of luster or brightness in the eyes frequently reflects the physical condition of the patient. And the eyes reveal the emotions, tensions, and reactions experienced by the patient. This may be their greatest diagnostic value. Thus far, external signs and symptoms apparent in the first view of the static surface anatomy have been considered. However, when the patient begins to speak, a new source of diagnostic aids becomes available. For it is then that he begins to reveal himself as a distinct personality, characterized by individual habits of facial expression, speech, and mannerisms. VITALITY
We have referred to the vitality factor as the fourth dimension of the patient.” It provides much diagnostic information if the dentist is trained to recognize and interpret the findings in relation to prosthodontic treatment.
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An analysis of anatomy in action begins when the dentist realizes that the benefits to be derived from it warrant its undertaking. The justification for such an analysis lies in this simple fact : dentures constructed with the patient comparatively inactive and with his face in repose will be worn when the patient returns to his role as an active individual carrying on such activities as talking, laughing, eating, coughing, or crying. Therefore, the dentist must construct inert appliances which will serve harmoniously as a part of the oral cavity and participate in its complex functions.6 The demands these functions place upon complete dentures necessitate a close observation of the patient’s habitual functional activities. The speech and facial expressions of the patient may be studied during the initial interview. The associated functions of breathing and swallowing may or may not pose prosthodontic problems. An analysis of these functions, to be meaningful, must be based on a normal, unstrained performance. The patient must be put at ease, and his interest must be directed toward his own problems. In recounting these, he is likely to become concerned to the extent of dropping any strained or false mannerisms of expression. The request “Tell me about your teeth” generally accomplishesthis purpose. During the patient’s response, a twofold evaluation is made: the first is based upon factual information supplied by the idea content of the spoken words; the second is based on the quality of voice and speech plus the many and varied movements of the face accompanying the speechperformance. QUALITY
The inherent quality of voice and speech is a major area of identification of the individual0 This is evident in the listener’s ability to recognize the voice of an acquaintance on the telephone before he identifies himself by name. Personal speech characteristics result from variations in anatomic structural makeup, dialectic influences, state of general health, speech training, and racial influences. VITALITY
The vitality factor of an individual’s speech is closely related to that of his physical and mental state. Markedly slow, weak speech may result from a weakened physical condition and may indicate the need for a complete medical examination. Vital forces of speech may vary from morning to evening, and these variations may be so extreme that they affect prosthodontic procedures which utilize speech or speech movements. Judson and Weaver7 state, “Neurological patterns of speech are most similar in persons having similar vital capacities.” SPEECH
Speech sometimes serves as an aid in the.initial, classification of a patient. Rapid, jerky speechis frequently characteristic of a hysterical patient. The exacting
patient often displays forcefulness and abrupt speech qualities in placing his questions and stating his demands. In contrast to these patients, the speech of the philosophic or indifferent patients is usually less forceful and of a more even rate. The indifferent patient frequently has a monotone quality in his speech which may occur as a result of his lack of interest and certainly reflects the absence of enthusiasm. Obviously, there are exceptions to these indicated associations of general speech characteristics and patient classification. Thus far, speech, as a diagnostic aid, has been considered only generally, in relation to its vigor, rate, and identifying qualities. As the patient continues to talk, the trained observer will note any repeated imperfections or lack of precision in speech performance which may indicate a speech defect. Detection of such defects and an understanding of their causes is important to prosthodontic diagnosis. SPEECH
Many persons are not aware that they have speech defects. If such a defect is noted in a patient during the preliminary interview, it should be called to his attention prior to the start of any dental treatment. Preoperative speech recordings during the preliminary interview enable the patient to hear his own voice as it sounds to others and to note defects of which he may not have been aware. Speech defects that have existed from birth generally require the services of a speech therapist for correction because the defect existed before the speech pattern was established. Dkfects of speech resulting from changes in the oral cavity which occur after the speech pattern has been established, such as the loss of teeth, seldom require speech therapy. Some speech defects are accompa&d by changes in facial expression, and they result from (1 j a defective dentition, (2) defective dentures, (3) ill health, or (4) geriatric changes. A patient who has lost most of the teeth and has never had them replaced reflects speech modifications. During the period in which the teeth have been lost, he has been forced to make certain adaptive movements to compensate for these losses in order to continue to engage in understandable speech. The ability to accommodate when oral structures are lost is evidenced by the fact that people with no teeth or with ill-fitting dentures continue to speak and to be understood. EFFECTS
The loss of posterior teeth results in spreading of the tongue. The loss of anterior teeth and supporting structures reduces lip support. The failure to replace missing teeth causes a drifting of remaining teeth and changes in occlusion. Thus, three of the main articulators in speech (tongue, lips, and teeth) have been modified. The fundamental role of these articulators is in the production of consonantal sounds, which require impedance or checking of the airstream to occur.B DEFECTS
Even under ideal conditions, i.e., when a speaker has a full complement of natural teeth in near normal positions, the consonants s and z present more difficult>
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in pronunciation and are less pleasing to the ear than any other consonants9 It follows, therefore, that the consonants s and z are of major concern in prosthodontic treatment. Defects in their pronunciation by denture patients may be caused by (1) the inability of the tongue and lips to perform precise, firm movements in directing the stream of air, (2) too large an interocclusal distance, (3) missing or malpositioned teeth, (4) wide diastemas, or (5) lack of auditory acuity. This first factor should suggest an evaluation of the existing arch width and the palatal height and form. Clinical testing procedures may be accomplished by modifying the tooth-palatal relationship of the old dentures. If the palatal arch form is too narrow in the premolar regions and crowds the tongue, it should be widened to permit the bracing of the sides of the tongue against the teeth in order that the middle of the tongue may be properly grooved. If the V-shaped space between the middle of the tongue and the palate is too deep, causing whistling, the denture should be modified to reduce this space. If the V-shaped space is too small, causing lisping, the denture may be modified to enlarge the space. The quality of these sounds may sometimes be improved by changing the existing surface texture of the denture or reducing its palatal thickness to create more tongue space. Testing procedures which prove effective should be noted for reference when new dentures are constructed. Although the fifth cause is not directly under the treatment of the dentist, he should be aware that it can be responsible for unpleasant hissing sounds in the pronunciation of s and z. If such a defect is noted and it is not of dental origin, the patient should be instructed to have necessary examinations and treatment for hearing loss. Defects in the pronunciation of the consonants f and v are most often caused by the inability of the mandibular lip to contact the maxillary incisors properly. Observation should be made of the length and position of the maxillary anterior teeth while the patient is saying “five” and “valve” or words which contain these labiodental sounds. The teeth should come into slight end to end contact with the center of the mandibular lip. Defects in the pronunciation of the consonants t and d are often due to placement of the maxillary anterior teeth too far palatally. These linguopalatal sounds are produced when the tongue articulates against the maxillary teeth and palate. Therefore, if the tongue contacts the teeth and palate too soon, the sound cannot be made properly. An analysis of speech defects can suggest desirable changes in the dentures to be constructed. FACIAL
Various facial movements accompany the activity of speech and may occur apart from the function of speech as a separate means of expression. The anatomy of facial expression and its prosthodontic significance have been discussed.lO There are many reasons for including facial expression in the functional analysis of a patient. Movements of facial expression are generally habitual. They are frequently vigorous movements employing muscles adjacent to dentures and can,
therefore, exert dislodging pressures. The activity of facial expression is engaged in many hours of the day, as is speech. The teeth are revealed in varying degrees during various types of facial expression. A deteriorating dentition or unsightly dentures can be responsible for an individual acquiring compensatory facial expressions to conceal a dental deformity. Whether or not the dentist recognizes the importance of the function of facial expression, he must contend with its forces throughout the treatment of his prosthodontic patient. Recognition of these forces in the diagnostic phase enables the dentist to anticipate them in treatment planning and construction. SIGNIFICANT
Certain types of facial movements have particular significance in treatment planning. Exaggerated movements of the cheeks or lips during speech must have allowances incorporated for them in the dentures. This can be done by having the patient perform these or similar movements during the development of impressions. Further allowances can be made in the positioning of the teeth and finishing of the denture bases. Rapid, powerful tongue movements used in speech can be compensated by having the patient go through exaggerated tongue movements, directed by the dentist, during impression procedures. Another approach to this problem is to place a physiologic impression material in the old dentures and permit the patient to mold this material during his normal speech activities. Proper positioning of the teeth and allowances in the denture bases also provide for these movements. Compensatory movements of the cheeks, lips, and tongue acquired to conceal unsightly dentures or to stabilize ill-fitting ones frequently cease when the situation responsible for them has been corrected. However, if the movements have been performed over a long period of time, the patient may not realize he performs them or why he acquired them. Then the dentist must employ educational psychology. He must point out to the patient the compensatory movements he is making, explain why he developed them, and convince him that they are no longer necessary. Movements employed to conceal unsightly dentures are usually those which compress the lips tightly, hindering speech and limiting smiling and laughing. Pride in personal appearance is a strong motivating force to encourage the patient tn abandon these compensatory movements. Swallowing is frequently used to stabilize ill-fitting dentures because in this activity there are (1) a pursing of the lips which prevents a forward thrust of the dentures, (2) a thrust of the tongue to the palate which seats the maxillary denture, and (3) an elevation of the mandible which stabilizes the mandibular denture against the maxillary denture. Continual repetition of this compensatory activity can produce sore spots, the cause of which ma! not be recognized by the patient. Correction of the occlusion or removal of one of the dentures should be considered in the diagnostic study and preliminary treatment program. Mandibular movements acquired to produce maximal tooth contact for stabilizing or reseating dentures pose a problem in that there is a possibility of recording
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of the same
maxillary arch showing occurred in 11 years.
this acquired eccentric maxillomandibular relation and perpetuating a series of errors. One or both of the old dentures should be left out of the mouth or the old dentures corrected to alleviate the condition before new dentures are constructed. HABITUAL
Habitual facial expressions employing exaggerated movements of the elevators and depressors of the lips can be dislodging forces to dentures unless these movements are recognized and allowances are made for them. Facial expressions indicative of neuromuscular disorders and unusual unilateral facial expressions are of concern to the dentist particularly in recording maxillomandibular relationships. These situations make it difficult to record the centric relation to be used as a reference relation. A provisional occlusal scheme
should be developed utilizing cuspless acrylic resin teeth. This will enable the dentist to make a periodic occlusal analysis and modify the initial occlusa1 scheme. This is an example of progressive diagnosis. An analysis of anatomy in action provides the basis for the treatment plan and for a meaningful clinical examination of the mouth and dentures. DIAGNOSTIC
In approaching the intraoral study, it is advisable first to consider how the examination of the edentulous mouth varies from that of the mouth with natural teeth. Gone are the fixed landmarks of natural teeth which previously served as support, points of reference, and guidelines for earlier examinations and treatment plans. Accompanying the loss of teeth is the loss of other supporting structures as well as changes in those which remain. Soft structures of muscles, ligaments, mucous membrane, and skin are altered in their attachments and functional activities. These structural changes have a marked effect on facial contours and are responsible for decrease in facial length, loss of muscular tone and power, and impairment, in whole or in part, of the many functions performed in or about the mouth. Neuromuscular patterns, established prior to the structural loss, are radically affected by the loss or change of supporting structures, and compensator! patterns have been developed to permit the performance of the various functions. Patients differ in their abilities to adapt to such changes, and this factor of adaptability must be taken into account in the development of a treatment program. Ryanll states : “Injury or disease of the body produces changes in feeling, tone, and emotional responses. The one word, psychosomatic, defines organismal unity and totality-no treatment can be either psychic or somatic. Every treatment is both.” But the current loss or change observed is only part of the story. Existing supporting structures and tissues will be subject to continued undesirable change, and such changes must be anticipated (Fig. 1). The condition, variations, and functional relationships of the structures and tissues to each other and to complete dentures must be evaluated (Fig. 2). Existing conditions and anticipated changes must then be correctly interpreted in order to project realistically the prosthodontic pc~sibilities and limitations of the patient. DIAGNOSTIC
The diagnostic approach should have as its objective the restoration of function. The clinical examination is a means for anticipating functional restoration through a critical evaluation of the remaining structures and their relationship to each other in various functions. Such relationships have been excellently recorded in three films available to the profession.12-14 Since restoration of various functions is a major objective of prosthodontic treatment, the requirements for such restoration must be considered in the initial diagnosis of the foundation which is to support the dentures that are to promote the functions. Three acts are performed almost simultaneously in the examination of an edentulous mouth : (1) observation, (2) interpretation, and (3) visualization.
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Evidence of a structural loss is observed ; the loss is interpreted as it has impaired various functions, and the restoration of the lost structure is visualized as it will improve functional performance. Structural changes are observed ; these changes are interpreted as they have impaired various functions, and the possibilities of structural preservation are visualized as they will improve functional performance. Rela’tionship changes are observed ; they are interpreted as they have impaired vaiious functions, and modifications of these relationships are visualized as they will improve functional performance. The analysis must be made in terms of ratios and proportion. The ratios of loss or change in structures and relationships must be related to functional impairment in an attempt to improve functional performances by adequate replacements (Fig. 3). This analysis calls for the application of functional anatomy and physiology. Without this knowledge and its application in the initial diagnosis, the construction of dentures that will promote the various functions is an impossibility. To believe that adequate dentures can be produced by the use of a wonder material or an arbitrary procedure employed as a substitute for such knowledge is a fallacy which leads to failures in treatment. EFFECT
During growth and development of the teeth and their supporting structures, the inner walls of the lips and cheeks serve as outer boundary limitations, whereas
Fig. 2.-A, An edentulous maxillary arch. B, The same arch 2 yeam later shows structural and changes which had occurred. Note the reduction in the size of the ridge, the irregularity of the ridge, and the change in the relationships of the frenal attachments. 1OSSes
x%2 ‘5” PHENOMENON
Fig. 3.-The areas af attachments of muscles are indicated on two edentulous mandibles and one mandible showing no apparent structural losses: (1) mentalis; (2) quadratus labil inferioris; (3) [email protected]
(4) platysma; (5) buccinator; (6) mylohyoid; (7) genioglossus. Note on the edentulous mandibles the migration of the attachments of the mentalis, genioglossus, and buccinator muscles. The migration of these attachments changes their relations to the other muscle attachments. In the mandible on the left, the alveolar process has been resorbed. The mentalis muscles have migrated lingually and are approximating the genioglossus muscle. The buccinator muscles have migrated lingually and are approximating the mylohyoid muscles. This bone loss and subsequent change in muscular attachments reduces the potential denture space and changes the foundational support in these areas.
the tongue forms the powerful inner boundary of these structures and the palate. The teeth, their supporting structures, and the palate derive their alignment, shape, and form from and are retained in a neutral position because of the equal and opposing pressures produced on both si&s+‘bf these structures by functional activities of sucking, eating, swallowing, sp&kjng, and facial expressions. These principles of growth and development are involved in positioning of teeth by using the lips, cheeks, and tongue as guides and as stabilizing influences on dentures in the edentulous mouth. In an edentulous mouth with atrophied ridges, the lips, cheeks, and tongue may be dislodging forces to the dentures. However, patients can be trained to utilize these structures in such a way that they will stabilize dentures. The results of this training will assist the dentist during the construction phase and aid patients in adapting to dentures. LIPS
The lips are second only to the tongue in the variety and degree of functional movements that take place in the mouth region. They are the initiators of mastication and the finalizers of speech and, as boundaries in the edentulous mouth, place many limitations on complete dentures. Because of lack of support in the edentulous mouth, the lips (the curtains of the mouth) collapse and are drawn inward. The maxillary lip is more noticeably affected than other facial features when this support, made up of teeth, bone, and soft tissues, has been removed. This collapse reduces the prominence of three labial anatomic landmarks: the philtrum, the red zone or vermilion border of the lips, and the opening of the mouth ; it lowers
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the corners of the mouth. The use of these landmarks as diagnostic guides can determine the proper lip support by the new dentures required to restore them. The amount of space between the residual alveolar ridge and the lips during functional activities must be considered in relation to the denture flanges. Dentures are frequently constructed with the lips in repose and without regard for overactive mentalis mus&s. These muscles, when functioning, will reduce the labial vestibular space and tend to dislodge the mandibular denture.l$ The overfilling of this vestibular space with the denture flanges and malpositioning of the teeth can have a marked effect on speech, particularly in plosive and f and v sounds. If overfilled, it will eradicate the normal mentolabial sulcus. MODIOLUS
The muscles of the lips and cheek converge into a thick, mobile hub region called the modiolus, which is slightly inferior and distal to the corner of the mouth. This region is supported primarily by the maxillary teeth. It can be fixed instantly and moved voluntarily. In an edentulous mouth, the mod-ioli assume a sagging position, become less active, diminish in size, and change in shape. This malposition and loss of tonicity,
Fig. 4 .-A mandibular complete denture to which a rubber-base impression material has been applied to record the functional movements of the tissues surrounding the denture. After the analysis of the denture and the functional conditions, the “model” may be used as a guide to locate the potential denture space.
caused by lack of tooth support, can produce leakage of food, liquids, and saliva at the corners of the mouth and result in angular cheilosis and a downward cast in these regions. A digital examination of the modiolus is made by placing the index finger in the buccal pouch or vestibule on the inner surface of the cheek and the thumb on the outer surface of the cheek and directing the patient to swallow. Observations of these highly functional landmarks should be made in relation to their size, development, and flexibility. The mandibular denture should be visualized in relation to the allowances necessary to accommodate for this muscle mass and the extreme movements and flexibility in positions to which it was accustomed when natural teeth were present.
The modioli can be used to an advantage in stabilizing the maxillary denture by placement of the maxillary premolars in a position above them. Thus, during functional activities involving elevation of the lips, there are fixing and elevation of the modioli and uplifting of the maxillary denture.16 By directing the patient to smile, the dentist can use the modioli as reference points in determining the occlusal plane to develop the smiling line. The application of these two principles changes the shape of the mouth by uplifting its corners and creating more pleasant contours.
Fig. 5.- Intraoral views of an edentulous mouth: (R) atrophied ridge; (S) dominant sub lingual structures; (8) buccal shelf. Note the relationship of the sublingual structures to the ridge and buccal shelf aa the tongue is moved from A, a retruded position, to B, a slightly forward, elevated position, to C, an extremely forward, elevated position. This tongue movement results in the sublingual structures covering the ridge, as shown in B, and in raising the entire floor of the mouth, as shown in C. The determination of the correct potential denture space becomes a critfcai factor in a mouth with an atrophied ridge and dominant subhngual structures.
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The tongue is a powerful and extremely adaptable organ. Observations of the position of the tongue should be made with the mouth relaxed and about half open. If the tongue is in a retruded position, it may dislodge the mandibular denture by raising the lingual flanges and permitting air to get under them. However, if the tongue is in a forward position, resting on the mandibular anterior ridge, it will serve as a stabilizer to the mandibular denture .17Js Because of the great adaptability of the tongue, patients may be trained by conditioning exercises to reposition the tongue from an unfavorable to a more favorable position. During swallowing, the teeth serve as limiting boundaries to the inward movements of the cheeks and lips and to the upward and outward movements of the tongue and sublingual structures. The region housing the teeth and alveolar supporting structures has been called variously “the neutral zone,“iO “a dead space,“zo and “the potential denture space.J’21,22 This space is difficult to locate because of (1) the changes in the alveolar ridge, (2) the approximation of the tongue and cheeks in their attempts to fill this region, (3) the reorientation of muscular attachments which changes the structural relationships, (4) the constantly changing shape and position of the tongue during functional activities, and (5) the closed position of the lips during certain of these activities. I If the old dentures were made in accordance with the principles of good denture construction, they can be used in two practical procedures for locating this space. These procedures can provide a diagnostic record and an evaluation of the dentures as they relate to the existing conditions. This first procedure is used when the dentures must be returned to the patient. A thin mix of alginate impression material can be added to the entire surface of the clean, dry mandibular denture, which is then seated in the dry mouth of the patient. With the maxillary denture in place, the patient is instructed to swallow, move the lips and cheeks slightly, suck, swallow again, and then hold the teeth together until the a&ate is set. An analysis can then be made of the mandibular denture and the available space in light of functional conditions. The same procedure can be used in analyzing the maxillary denture. If any
Fig. 6.-A hemisection of an edentulous mouth Note the juncture (J) with a soft palate (SP) of gentle the degrees of slope for class 2 and class 3 soft palates.
with a tit-appearing slope (class 1). The
palate (HP). lines indicate
Fig. ‘7.-Hemisections of the hard and soft palate the lips (L) supported by teeth and alveolar process (A). (HP) and its juncture (J) with the soft palate (SP) which mouth showing loss of support for the lips (L). Note the juncture (J) with the soft palate, which also has an acute
regions. A, A dentulous mouth with Note the high vault of the hard palate has an acute drop. B, An edentulous flat-appearing hard palate (HP) and its slope.
parts of the dentures show through the impression material, it indicates that the dentures are overextended in these areas. The dentures should be relieved in areas showing through the impression material before the procedure is repeated, to make a more accurate diagnosis. 23 Diagnostic casts can be made from these impressions for use as reference guides in the construction of the new complete dentures. The second procedure can be used when it is unnecessary or inadvisable to return the old dentures to the patient. A rubber-base or zinc oxide-eugenol impression material is applied to all of the surfaces of the denture except the occlusal surface (Fig. 4). The same steps as were described in the first procedure are followed. After the analysis of the denture has been completed, the excessive impression material is trimmed away, and the entire “model” is preserved. It may then be used as it is, without making a cast, for a reference guide to locate the potential denture space. I have found this procedure to be simple and accurate. The structures under the tongue are of concern particularly when they are in an abnormal functional relationship to the mandibular ridge. Because of the comparative delicacy of these structures, they are difficult to record without displacement. A technique that will control them without undesirable distortion must be selected. As the residual alveolar ridge becomes smaller, these sublingual structures become more dominant in their functional relation to the residual ridge (Fig. 5).
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When these unfavorable conditions are observed, consideration must be given to them both before and during the construction of dentures. Such considerations include the development of an accurate mandibular tray from a functional impression, making of an accurate final impression, and the possibility of using a metal base to af?ord additional weight in the mandibular denture. PALATE
The hard and soft palates, although structurally and functionally different, have an important relationship to each other. The variations of this relationship can be classified (Fig. 6). Class 1 indicates a low, flat vault in the hard palate which continues into a soft palate that has a minimal amount of drop and movement. This situation provides a broader posterior palatal seal area and permits a more distal extension of the maxillary denture. Class 3 indicates a high vault in the hard palate and an acute drop and maximal movement in the soft palate. The region where this acute drop occurs becomes extremely critical because it will accommodate only a narrow posterior palatal seal, and it places greater limitations on the distal extension of the maxillary denture. Class 2 designates those which are intermediary. Such relationships are not difficult to recognize in a mouth with natural teeth or even in an edentulous mouth which has alveolar ridges. However, in an atrophied edentulous mouth, the diagnosis of this relationship may be difficult (Fig. 7). The difficulty is caused by the flattened appearance of the hard palate, resulting from the loss of teeth and from the atrophy of the maxillae which reduces its size. This flat-appearing hard palate does not necessarily connote a gently sloping soft palate which is comparatively inflexible. The illusion produced by structural loss or changes in the hard palate must be recognized so it does not influence the diagnosis of the soft palate. The activity and drop of the soft palate remain the same as they were prior to the loss of teeth. Errors in diagnosis at this point can result in dentures which must be corrected before the patient will be able to tolerate them or use them successfully. DIAGNOSTIC
During clinical examination, various records can and should be obtained to provide additional diagnostic information. These records should include such information as (1) mental attitude, (2) dental history of natural teeth, reasons for loss, and sequence of loss, (3) pre-extraction records, (4) length of edentulousness, (5) previous denture history, (6) esthetic possibilities and limitations, (7) roentgenographic findings, (8) oral health, including color and condition of mucosa, pathologic states, and hard and soft areas, (9) condition and amount of saliva, (10) ridge conditions, including size, form, shape, and relations, and (11) arch form. Any record that assists in the evaluation of the patient’s needs is desirable. A record that is made and then ignored serves no purpose. A functional record which is not commonly mentioned is the recording of the patient’s speech. This phonetic record is easily obtained, serves several purposes throughout the treatment and postinsertion phases of denture service, and provides a permanent record of an important functional performance. Phonetic recordings
of the consultation interview provide a permanent record of what the patient has been told in relation to his treatment program. Legally, they constitute more acceptable records than written notes. ADDITIONAL
Clinical examination includes a critical analysis of the present dentures and the condition of the mouth tissues.These factors may indicate the need for a preliminary treatment program for the patient. Such a program may involve surgical operation, the patient going without dentures for a period of time,24 or conditioning exercises to stimulate tonus. When conditions are such that it is impossible for the patient to leave the dentures out of the mouth, procedures of tissue-conditioning treatment by use of a soft resilient material in the old dentures have been suggested.18,26,27 Such procedures have merit in the concept of treating the patient’s total needs. BOOSTS has suggested basic mandibular movement exercises (stretchrelax exercises) to assist in this conditioning. The value of exercises in facial expressions and speech should also be considered. SUMMARY
Some aspects of functional anatomy and speech have been discussed in relation to diagnosis of edentulous mouths for dentures. However, if we recognize the benefits of incorporating a fluid or progressive diagnostic approach in prosthodontic treatment, we know that we must continue, throughout that program, to study the functional performances occurring in the mouth region of the patient and to apply the additional knowledge gained to the procedural steps in denture construction. REFERENCES
Aid for Aging: More Comprehensive Denture Service, J.A.D.A. 1:Editorial: Statistical Abstract of the United States. Bureau of the Census. U. S. Commerce, 1961, p. 28.
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of Economic Research and Statistics, American Dental Association: Survey of Public Attitudes Regarding Dentures. III. Dentures Worn; Source of Dentures, J.A.D.A. 62:226, 1961. 4. Martone, A. L., and Edwards, L. F.: The Phenomenon of Function in Complete Denture Prosthodontics. Anatomy of the Mouth and Related Structures. I. The Face, J. PROS. DEN. 11:1006-1018, 1961. 5. Martone. A. L.. and Edwards. L. F.: The Phenomenon of Function in Comnlete Denture P;osthod&tics. Anatom; of the Mouth and Related Structures. If. &sculature of Expression, J. PROS. DEN. 12:4-27, 1962. 6. Martone, A. L., and Black, J. W.: The Phenomenon of Function in Complete Denture Prosthodontics. An Approach to Prosthodontics Through Speech Science. V. Speech Science Research of Prosthodontic Significance, J. PROS. DEN. 12:629-636. 1962 -_--.
7. Judson, L. S., and Weaver, A. T.: Voice Science, New York, 1942, Appleton-CenturyCrofts, Inc., p. 159. 8. Martone, A. L., and Black, J. W.: The Phenomenon of Function in Complete Denture Prosthodontics. An Approach to Prosthodontics Through Speech Science. IV. Physiology of Speech, J. PROS. DEN. 12:409-419, 1962. 9. Avery, E., Dorsey, J., and Sickels, V. A.: The First Principles of Speech, New York, 1929, D. Appleton and Company. Significance, J. 10. Martone, A. L.: Anatomy of Facial Expression and Its Prosthodontic PROS. DEN., 1962. To be published. 11. Ryan, E. J.: Psychobiologic Foundations in Dentistry, Springfield, Ill., 1946, Charles C Thomas, Publisher.
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12. Film-Syrop, H. M.: Intra Oral and Pharyngeal Structures and Their Movements, 23 minutes, sound, color, 1951. No. DT 44 in Audio Visual Materials in Dentistry, revised Jan. 1, 1960, Bureau of Audiovisual Service, American Dental Association. 13. Film-Central Office Film Library, U. S. Veterans Administration: Articulatory Movements in the Production of English Speech Sounds. I. Consonants, 25 minutes, sound, color, 1953. No. DT 77 in Audio Visual Materials in Dentistry, revised Jan. 1, 1960, Bureau of Audiovisual Service, American Dental Association. M.: The Physiology of Mastication, 18 minutes, silent, black and white, 14. Film-Klatsky, 1955. No. DT 62 in Audio Visual Materials in Dentistry, revised Jan. 1, 1960, Bureau of Audiovisual Service, American Dental Association. 1.5. Martone, A. L., and Edwards, L. F.: The Phenomenon of Function in Complete Denture Prosthodontics. Anatomy of the Mouth and Related Structures. III. Functional Anatomic Considerations, J. PROS. DEN. 12:207, 1962. 16. Fish, E. W.: Principles of Full Denture Construction, ed. 5, London, 1952, Staples Press, pp. 42-44. 17. Wright, C. R., Swartz, W. H., and Godwin, W. C.: Mandibular Denture Stability, Ann Arbor, 1961, The Overbeck Co., p. 46. 18. Shanahan, T. J.: Stabilizing Lower Dentures on Unfavorable Ridges, J. PROS. DEN. 12:420-424, 1962. Kingery, R. H. : Lecture notes. 8 Fish, E. W.: Principles of Full Denture Construction, ed. 5, London, 1952, Staples Press, pp. 34-35. 21. Roberts, A. L.: The Effects of ‘Outline and Form Upon Denture Stability and Retention, D. Clin. N. America, p. 301, July, 1960. 22. Nagle, R. J., and Sears, V. H.: Dental Prosthetics, St. Louis, 1958, The C. V. Mosby Company, p. 298. Sears, V. H. : Comprehensive Denture Service, J.A.D.A. 64:538, 1962. 2 Lytle, R. B.: Complete Denture Construction Based on a Study of the Deformation of the Underlying Soft Tissues, J. PROS. DEN. 9:539-551, 1959. 25. Boos, R. H.: Complete Denture Technique, Including Preparation and Conditioning, D. Clin. N. America, pp. 215-230, March, 1957. 26. Chase, W. W.: Tissue Conditioning Utilizing Dynamic Adaptive Stress, J. PROS. DEN. 11:804-815,.1961. 27. Pound, E. : Conditioning of Denture Patients, J.A.D.A. 64:461-468, 1962. 909
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