Achieving realism with complete dentures

COMPLETE

ACHIEVING DAYTON

DUNBAR

Mission,

Kan.

R

DENTURES

REALISM KRAJICEK,

WITH

COMPLETE

DENTURES

D.D.S.

EASON PROVES THE NECESSITY for including appearance as a vital part of the

treatment of each edentulous patient. The face is the “front” for the individual in all that he does. Therefore, restoring or preserving a natural appearance through complete dentures is a realistic objective. The value of appearance can no longer be considered controversial. It is of concern to every normal individual. Frequently, it can be the motivating force for personal self-confidence as well as successful business and social relationships. Whether we chooseto call it pride or human vanity, this is truly a strong emotional factor not to be disregarded. It exerts a definite influence on each denture patient. To ignore this facet of human behavior is to ignore people. Definite progress in the appearance phase of dentistry has been made in recent years. Although its full potential has not been achieved, antiquated and obsolete mechanical techniques of the past are being discarded so an improved esthetic service is now available to most dental patients. Unfortunately, a current esthetic concept stressesoversimplification of treatment methods for the dentist in an effort to conserve his valuable chair time. Actually, each patient presents specific and individual problems of appearancethat cannot be solved by any standardized laboratory method. Patients’ problems cannot be solved by relying on a system of averages. Prosthodontists cannot absolve themselves or be absolved of their responsibility for personally caring for an individual’s needs. This is especially pertinent in the appearance phaseof prosthodontic treatment. Dependence upon specific brands of commercial teeth or tooth systems, or adherence to programs which suggest assigning essential professional duties to the laboratory by prescription may constitute professional advancement for some, but the compromisesare difficult to justify for the dentist who has a personal regard for each of his patients. Any single concept is inadequate to solve all the requirements of natural dentofacial harmony. Only by using Nature as our guide and constantly studying natural dentitions can we provide a substantial foundation upon which to build our techniques. Read before the Southeastern Academy of Prosthodontics 229

in Birmingham,

Ala.

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Den. 1963

PSYCHODYNAMICS

Psychodynamics has been defined as “the systematized knowledge and theory of human behavior and its motivations.“r The oral cavity and teeth often become prominent factors which influence the behavior pattern of individuals beyond all bounds of normal reason. Perhaps no prosthetic practice is complete without this type of patient. Certainly, they serve to keep us aware of the continuing need for thorough examination, careful interrogation, and unhurried evaluation as useful tools in establishing a complete diagnosis. The true wants and needs should be known by the dentist prior to the treatment phase. If the diagnosis is inadequate and fails to disclose an existing psychosomatic problem of facial appearance, the dentist may discover too late that he is held responsible for some imagined denture failure when none exists. In our haste to get to the mechanical phase of denture construction, we must not overlook the value of diagnosis. Middle-aged women frequently request that denture borders be “plumpered” to remove wrinkles from the upper lip. It is often difficult to resist this desire, for the dentist reasons that it may serve to uphold the morale of the patient and build confidence. The practical approach, however, dictates that the patient be advised on the initial visit that only plastic surgeons can remove wrinkles. If we fail to fit the mind of the patient first, it is doubtful if we can ever fit the mouth. MUSCLE

TONUS

Muscle tone is an important consideration in the appearance of dentures, and it often receives too little attention in prosthodontic planning. Placing teeth lingual to their correct positions results in failure to provide normal support for the lips and cheeks. But, further, the muscle fibers involved are shortened so an atrophy of disuse in the facial musculature develops. Loss of natural contour of the facial muscles is detrimental to the normal and desired appearance of good health. On the other hand, excessive length or thickness of labial denture borders distends the lips and cheeks so that an illusion of tenseness and extreme fullness is given to the lower third of the face.2 Ideal muscle tonus about the oral cavity is a factor which demands our consideration. Constant stretching of muscle fibers beyond their normal length could lead to atrophy through continuous pressure. The philtrum, for example, is lost sometimes by overextending the upper denture border causing pressure atrophy of the upper incisal and nasal muscles. Nature demands function for health but it cannot tolerate force without intermission, The degree of firmness and tonal qualities of facial muscles are important in the esthetic development of complete dentures. Too often, the denture patient loses muscle tone needlessly. Illogical compromises are sometimes made to enhance appearance. Reference here is directed to the practice of increasing the vertical dimension of occlusion beyond the physiologic rest position of the mandible. To establish a vertical dimension of occlusion without sufficient free way space is to invite disaster. Each denture patient must be advised before treatment is instituted that modifications to enhance esthetic qualities for a short period of time will not be made at the expense of inducing permanent injury to intraoral tissues and/or facial muscles.

JMIMu;e;

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An insufficient vertical dimension produces unattractive changes in appear-ante. The chin comes too close to the nose, compresses the upper lip at the center, and permits the corners of the mouth to droop as in a scowl. This upward pressure in closing the mouth inverts and limits the vermilion border of the upper lip which gives it a thin quality in contrast to a prominent lower lip. Of even greater importance to the face are the obnoxious consequences of impaired muscle tonus. The orbicularis oris muscle has no direct attachment to the skeleton, while the muscle group known collectively as the muscles of facial expression all insert into the orbicularis oris. Overreduction of the vertical dimension of the face results in a functional imbalance of the superficial muscles of the head and neck. Evaluating and relating of these biologic factors to mechanical considerations is a serious obligation of the prosthodontist in the simulation of natural appearance for denture patients. Generally, the apical or basal bone immediately below and lateral to the anterior nasal spine remains intact and is not involved in resorptive bone changes. Alveolar bone is a specialized bone. It serves to house the roots of natural teeth. After the teeth are lost, its purpose has been accomplished and there is bone loss. This resorption, which is physiologically normal, determines the changing height of the residual ridge and usually continues only to the level of the apical ends of the teeth. After advanced resorption of the alveolar bone has occurred, further bone change of the residual ridge is minimal since the apical base remains fairly constant. For this reason, the superior one third of any maxillary denture border must be kept especially thin in the region of the central and lateral incisor teeth. Also, the lost alveolar process was originally inclined laterally and anteriorly from the residual crest of the ridge. The dentist must restore what the ravages of life have destroyed. This includes lost alveolar bone as well as teeth. So it is that anatomy and physiology are important to appearance. In fact, this aspect of complete denture construction embodies all that we do for a patient at every appointment visit. TOOTH

FACTORS

The contribution of individual anterior teeth to realism of the dental composition is self-evident. Although previously discussed principles exert a marked influence on reproducing natural conditions, we cannot avoid a discussion of the teeth or devising of a natural background for their placement. Far too many restorations with ekcellent retention and balanced occlusion are acceptable until the teeth become visible. Then the sudden discord between face and denture draws immediate attention to their artificiality. It is not difficult to incorporate naturalness into any denture procedure but to achieve this goal does involve more than raw materials. Most dentists and patients are overly concerned with selection of tooth mold and shade, while actually these factors are of minor importance to the composition. There is no system of tooth selection which can guarantee perfection, nor does the use of any specific brand of anterior teeth assure an esthetic result. Any standard followed too closely destroys the individuality of the denture and reduces the procedure to a mechanical routine of mass production.3

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The most important tooth factor in producing natural-appearing artificial restorations is that of tooth position. This is considered so vital in establishing naturalness between face and denture that a regular appointment visit is routinely scheduled to permit arranging teeth in the presence of the patient. SELECTION

OF TEETH

.Since the choice of anterior teeth to be used must precede positioning them in suitable bases, principles influencing the selection of individual teeth will be considered first. Nothing can relieve the dentist of his responsibility of choosing the exact size, shade, and form of individual teeth for each patient. Patients should be encouraged to participate in this phase of denture construction and their desires carefully considered. If conflicting opinions do arise regarding the choice of teeth, the wise dentist can wield an unobtrusive influence, since rapport will have been established and strengthened during previous visits .4 One of the most costly experiences to any prosthetic practice can be the selection of teeth without the approval and complete acceptance of the patient, since some change is inevitable. COLOR

Color selection of teeth should present no difficulties as the problem is not one of matching an existing shade but rather of knowing how to select basic colors appropriate for the individual’s face. To rely upon 2 or 3 numerical designations from a shade guide for use in all situations is inexcusable. In determining the shade for an edentulous patient we strive for color harmony. This is selecting teeth of a hue which will blend and conform with the general color pattern of the complexion, eyes, hair, and lips without being conspicuous. Natural teeth possess a delicate mingling of shades within teeth as well as variations of color from tooth to tooth. Using Nature as our guide, it becomes relatively unimportant, then, what specific shade of artificial tooth is selected but rather that a variety of shades be used to duplicate natural conditions. If we conscientiously avoid discords in color between the teeth and face, shade selection for the patient is an ever-changing factor. Just as the color of the skin and hair change with advancing age, so will the color of teeth require change to keep pace and harmonize with individual characteristics. Some people age more rapidly than others and so chronological age is not a valid measure of the dental age. The use of dark teeth for all older patients cannot hold true. Actually, some people retain youthful skin tones quite late in life. Dark teeth with varying shades of yellow or brown would surely result in complete disharmony of color for some older persons. SIZE

Research confirms the theory that there is a harmonious relationship between the size of teeth and faces. Berry6 reported that the upper central incisor was approximately one sixteenth the width of the face. Later, House6 supported these findings and provided a method of individual tooth selection based upon an average of tooth sizes in patients with pleasing natural dentitions.

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In this technique the dentist measures the 1)izygonlatic width of the face, expresses the distance in millimeters, and divides by 16. This provides the approximate width of each maxillary central incisor. Lateral incisors and cuspid teeth are chosen on the basis of harmonious breadth deviations from the previously determined width of the key (central incisor) teeth. This method of selecting approximate tooth size is not to be considered as infallible ; however, it is fundamentally more sound than the practice of measuring casts along the changing residual ridge crest. To subscribe to this latter method is to fill wide open spaces rather than edentulous faces. To choose harmonious teeth one must know about faces. In addition to tooth width, the thickness of artificial teeth from labial to lingual is generally not appreciated or given sufficient consideration. Both porcelain and acrylic resin teeth require bulk in order to achieve natural light reflection, realism of color depth, harmony of color pigmentations, and the quality of vitality which characterizes natural teeth from their artificial substitutes. If teeth that are too thin are used, they fail colorwise to create the image of naturalness, for the transparent qualities contrast harshly with the face. FORM

The basic outline form of artificial teeth has received more than its share of attention as a contributory factor to a natural appearance. Form of any tooth can be controlled by simply altering the pattern and contour of the wax matrix around its gingival end. The square, tapering, or ovoid characteristics can be achieved with one single tooth form. The practice of grinding and reshaping the mesiodistal and incisal contours of stock teeth prior to positioning them in the trial denture base is important. This eliminates the youthful appearance of teeth and harmonizes them with natural aging changes. Slight modifications give them an appearance of belonging. We should be aware that the labial form can contribute or detract from the effect of realism. Rounded or curved labial tooth surfaces appear more natural since they do not draw attention to the teeth by their boldness. This mildly softened effect seems to be noticeably more harmonious to faces. The use of hand-molded acrylic resin teeth which are true reflections of natural teeth create the most natural appearance that could be produced in artificial dentures. They look like teeth because they are true duplications of natural teeth in every detail. POSITION

Regardless of how carefully the maxillary wax rim is oriented in space and further contoured for ideal length and fullness, deviations from this form become most apparent as teeth are positioned by the dentist at chairside. The anterior teeth must be placed to support the facial musculature and still be in harmony with the face in repose and during speaking, laughing, and smiling. They must be pleasing in appearance and give the illusion of “belonging” when viewed by both the dentist and the patient.

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This requires that the dentist retain a mental image of the position of natural anterior teeth so that esthetic as well as functional harmony will be achieved. Both the anteroposterior position and vertical relationship with the residual ridge must be determined for each anterior tooth. As a tooth is placed, it is checked for appearance and function and shifted forward, backward, or downward until a harmonious positioning is evident. Further retesting indicates if additional changes are necessary. In Nature, the two maxillary central incisors are located anterior to the incisive papilla on the hard palate. We must do the same in positioning artificial teeth. Some have suggested there is a consistent measurement from the center of this papilla to the labial surface of the central incisors.’ This is dangerous for it tends to standardize a valuable control. If there is a correlation between this factor and arch form, or if it consistently varies from female to male, it has not been evident to me. It should be of sufficient importance to merely state that the central incisor teeth are always positioned to either side of, and somewhat in front of, the incisive papilla. Upper lip support is another valuable guiding factor. Normal lip support of the edentulous patient exists only when the tissues behind the vermilion border are supported by the teeth and base material to produce a pleasing outward curve of the lip from the profile view. Normal lip support is vitally important, not only to appearance, but to maintain the physiologic health and tone of the muscles of facial expression. The vertical positioning of upper anterior teeth is best determined by the functional factor of phonetics. The usual method of utilizing the upper lip in repose as a guide to the level of the incisal edge is a preliminary position only. In phonetics, as the patient pronounces the f and v sounds, the incisal edges of the upper teeth should contact the vermilion border of the lower lip at approximately the greatest height of its convexity. 8 The teeth contact the dorsal side of the tip of the tongue in the th sounds but without an obvious escape of air during pronunciation. The prime consideration in rotating artificial teeth naturally on their vertical axis is also a duplication of rotations in a natural dentition. The most dependable method of “breaking” the alignment is to select a cast of natural teeth which best harmonize with the patient’s characteristics, and then faithfully imitate these tooth positions. When the arrangement from such a cast is copied, natural irregularities will be introduced to produce a balanced relationship between the mouth and face. SUMMARY

Dentists vary in artistic ability to construct artificial dentures so natural in appearance that they are not easily detectable. However, by sincere application of the guiding factors discussed in this article, the quality of all complete dentures could be improved. This requires both time and effort by the dentist. Still, if there is never time to do things right, when will there ever be time to do them over? A sincere effort has been made to help dentists construct complete dentures which look like natural teeth by carefully studying and imitating natural teeth and their arrangement.

Volun1e Number

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REFERENCES

1. Moses,

C. H.: Psychodynamics and Biologic Studies as They Concern the Prosthodontist, J. D. Med. 16:84-93, 1961. 2. Krajicek, D. D.: Simulation of Natural Appearance, J. PROS. DEN. 12:28-33, 1962. 3. Richey, E. L. : Esthetics : Selection of Teeth and Correlated Factors, J.A.D.A. 28:1270-1277, 1941. 4. Porter, l$6F: A Rational Concept in Complete Denture Construction, Texas D. J. 79:4-7, 5. Berry, 6. House, 7.

McGee,

8.

Pound,

SHAWNEE

F. H.: Is the Theory of Temperaments the Foundation of the Study of Prosthetic Art? D. Mag. 1:405, 1905-1906. M. M.: Form and Color Harmony in Denture Art, Whittier, Calif., 1939, House and Loop, p. 17. G. F.: Tooth Placement and Base Contour in Denture Construction, J. PROS. DEN. 10:651-657,196O. E.: Applying Harmony in Selecting and Arranging Teeth, D. Clin. N. America, pp. 241-258, March, 1962. MISSION

MEDICAL

6100 MARTWAY-SUITE MISSION, KAN.

20

CIRCLE