REMOVABLE LOUIS

PROSTHODONTICS

BLATTERFEIN,

Controlling and

ROBERT

anomalies

M. MORROW,

of vertical

S. HOWARD

PAYNE, Section editors

dimension

speech

Earl Pound,

D.D.S.

Westlake Village, Calif.

V

arious articles have been written concerning edentulous patients for whom phonetics and esthetics have been used as controls for establishing the vertical dimension of occlusion, centric occlusion, and incisal guidance and ascertaining their original class of occlusion.l+ This article on the same basic subjects has a three-fold purpose: ( 1) to serve as a progress report on refining some of the previously questionable areas; (2) to cover in greater depth the validity and fluidity of the controls offered by this approach ; and (3 ) to discuss in detail ways and means of recognizing and managing edentulous patients in whom atypical and abnormal problems of occlusion and speech previously existed. Since it is difficult to ascertain the most functional vertical dimension of occlusion for the edentulous patient, controls are suggested. The importance of applying these guidelines to restorative dentistry also will be discussed. PROBLEMS

OF CONTROL

A serious problem facing the prosthodontist is that the anterior stop of the patient’s mandible has been lost, and the only remaining controls are the fixed but fluid temporomandibular joints and the dependable but fluid musculature which controls the joint’s movements. These two controls are all that are actually needed. Ry utilizing their specific ranges and types of movement, the former relations of the suspended mandible with the static maxillae can be easily re-established. To restore these relations with functional accuracy, the first step is to establish a static spatial control point on the maxillae to simulate the incisal edge of naturally positioned anterior teeth (Fig. 1, A). The next step is to locate the position of the Read and demonstrated before the International and the American Prosthodontic Society.

Academy

of Dentistry,

Tokyo,

Japan,

This article is being published simultaneously in THE JOURNAL OF PROSTHETIC DENTISTRY and the California Dental Association Journal by special arrangement between the editors.

124

Controlling

vertical

dimension

and speech

125

Fig. 1. Re-establishing anterior maxillomandibular relations requires two controls. (A) On the maxillae, a spatial but solid control is oriented to simulate the former position of the incisal edges of the central incisors. (B) On the mandible, the control is the anterior ridge. When enunciating /S/ sounds, this becomes an accurate spatial control, because it is the most forward and vertical position this bone assumes during speech. Between this bone and the upper control, lost bone and teeth can be repeatedly correlated to the /S/ clearance.

Fig. 2. This classic /S/

position

shows the 1 mm. of incisal space necessary for the /S/

Fig. 3. The varying degrees of retrusion patients (illustrated in Class I automation,

and closure CZ2).

to develop

verti-centric

are found

whistle. in all

lower anterior teeth on the mandible so that their incisal edges will relate properly with this upper tooth position. The second positive control which is used to restore relations is the position of the remaining anterior ridge of the mandible. When enunciating the /S/ sound accurately and repeatedly, the previously developed range of muscular mandibular movements will position this anterior segment in the most forward and most vertical position ever assumed during speech (Fig. 1, B). This permits the dentist to restore on this bony foundation the lost bone structure and to angle the new teeth to this /S/ position. This usually means that only 1 mm. of space will exist between the incisal edges of the upper and lower teeth when the /S/ sounds are being used (Fig. 2). When the anterior teeth are set to this position, another control is automatically developed. By having the patient touch these incisal edges together, the resultant

126

Pound

I. Prosthet. Auquat,

ANALYTICAL

CONTROL

SET UP MAXILLARY

t

CHART

b

b

SHORT AND ANGLED WAXES USUALLY DEVELOP AN ATYP(CAL “S” POSlTlON WlTH MlNOR CHANGESINTHEUPPERTEETH

c7

b

ca

REPLACE

NO “S” IS POSSlSLE ON THE LONG WAX AND A FEW OF THE SHORT AND ANGLEDONES(TONGUETHRUSTERS1

I

SPEAKING

WAX WITH

2 OR 4 INCISORS

REFINE

“S”

USE SPEECH AND ESTHETICS REFINE TOOTH POSITION

CLEARANCE

TO

C,,

1 DETERMINE IF ON UPPER

AETRUDED

TEETH

CONTACT

1 IF ON PALATAL

J

RECORD VERTI-CENTRIC BY RETRUSlON AND CLOSVRE. BY THE SWALLOWING TECHNIQUE OR BY AN,’ DESIRED METHOD NONE IS DEPENDABLE I

BY

I MOUNT

SET UP ALL TEETH

EXCEPT

I cl5

t

CASTS

IN ARTICULATOR

THE LOWER

POSTERIORS.

OF CHOICE USE A FLAT WAX RIM IN THEIR

PLACE.

Cl6

A

I

1

Cl3

TISSUES

1

I

RECORD VERTI-CENTRIC RETRUSlON ANDCLOSURE

+ Cl6

C8

4

i

Cl4

cc~

b

J

Cl2

f

c

RESET WAX TO A NORMAL ANGLE AND A LENGTH EQUAL TO LOST BONE AND TOOTH STRUCTURE. TRY TO DEVELOP AN ATYPICAL “S” POSITION.

b

Cl0

Cl

TEETH

I

.

I1

ANTERIOR

I

I

!-

Dent. 1976

I REFINE ESTHETICS REFINE ‘3” CLEARANCE SET INCISAL GUIDANCE

DISREGARD THE LOWER TO 1 5 MM OF SPEAKING VERTICAL DIMENSION

MAKING DIAGNOSTIC VlSED FOR THESE PERMlTS REFINING. PROBLEMS. LINEAR THEM EARL POUND,

TEETH SPACE, USABLE

ADJUST THE WAX RIM THIS IS THE GREATEST IF A DECREASE IS

DENTURES IS STRONGLY ADTYPES OF OCCLUSIONS THIS THROUGH USE, THEIR EXISTING DENTURES MIGHT PERPETUATE

r-ic20

DDS1975’

Fig. 4. By recognizing phonetic clearances that exist between upper and lower anterior and posterior teeth during normal speech, this control chart permits one to identify patients that had atypical or abnormal occlusions and speech. It suggests (CZ8 and C20) a control for establishing their jaw relations.

point of contact represents the anterior phase of incisal guidance. The posterior phase of incisal guidance is then located by using two simple, automated, easily controlled mandibular movements. First, the mandible is retruded from this position to a comfortable hinge relation, and then it is closed until the lower anterior teeth make contact at any point. This point of contact, in the vast majority of patients, represents

Volume 36 Number 2

Controlling

vertirol

dimension

and speech

127

not only the completion of the incisal guide angle but also the vertical dimension of occlusion and the centric relation of the mandible (Fig. 3). However, about 25 per cent of patients do not function in this specific manner so that developing clarity of speech and determining their former jaw relations are not easy. Solving their problems can be simplified by utilizing the Analytical Control Chart (Fig. 4). It identifies the problems as they occur and helps the dentist achieve the desired result. In the chart, each step is identified with a control number, such as C2, where “speaking” wax is used. To fully understand the controls used and also the validity of this approach, a series of definitions, principles, and concepts are reviewed. EXPLANATION

OF TERMS

Anatomic harmony. This refers to replacing the length and angle of any lost teeth and their former bone support so that their continuity to the remaining structures is natural (C6). Speaking space. This is the interocclusal space which exists between the posterior teeth when the patient is enunciating /S/ sounds. It is not related to the interocclusal space of rest position. It represents the difference between the vertical dimension of occlusion and the clearance between the teeth when /S/ sounds are spoken (C18). Diagnostic dentures. These are temporary dentures lined with tissue-conditioning material which are used to rehabilitate oral and facial structures and to equilibrate the temporomandibular joints. They also permit experimentation with tooth position and jaw relations (C20). Automation. This term refers to the use of the limitations of muscular activity for positioning lower anterior teeth and recording “verti-centric” (C14). Verti-centric. This is the term used to indicate the simultaneous recordings of vertical dimension and centric occlusion (Cl4). CLARIFYING

STATEMENTS

( 1) The /S/ sound is a subtle whistle which can only be produced when air is forced between two hard surfaces (C2). (2) The cla-ssic /S/ sound is produced when air is forced between the upper and lower incisors when their incisal edges are about 1 mm. apart. This /S/ position exists in about 75 per cent of patients (C.3). (3) I’n about 20 per cent of patients, the 1 mm. /S/ clearance occurs on the lingual surfaces of the incisors. These patients are classified as “atypical” (C7). (4) A sharp /S/ cannot be developed if the tongue serves as one of the two surfaces (C7). (5) About 5 per cent of patients are classified as “abnormal.” These patients are usually tongue thrusters, and they use the tongue as the inferior surface for air control when trying to make /S/ sounds. Their /S/ sounds are never sharp (C9). (6) During any classic or atypical /S/ position, the mandible is placed in the most forward and vertical position it ever assumes during speech (C3, C7). (7) The mandible’s forward movement from its hinge position when speaking can vary from 0 to about 10 mm. (C12, C13).

J. l’rosthet. Dent. Augmt, 19X

Fig. 5. Original

incisal guide angles are automatically results on tooth surfaces.

Fig. 6. ‘Typical Classes I, II, and III Class II contacts can vary considerably.

verti-centric

established

contacts.

if the contact

Classes I and III

of retrusion

vary

minutely;

(8) When /S/ sounds are being enunciated, the mandible always moues dozeInward from its vertical dimension of occlusion to the level of its /S/ position. The resultant posterior interocclusal space is known as the speaking space (Cl 8). (9) The doLeInward and forward mandibular movements which occur when /S/ sounds are repeatedly enunciated during rapid speech are constant with all patients, and the most forward point of the mandibular ridge can be used as a functional mandibular control point (Fig. 1, B) (10) During speech, no teeth or denture parts should contact one another. (11) The /S/ position is the point at which any tooth will come closest to contacting another during speech (Fig. 2). ( 12) /S/ sounds followed immediately with a vowel in the same word create the most forward mandibular movements of speech. (13) The ideal /S/ clearance is developed when arranging the anterior teeth by having the patient use frequent /S/ sounds during rapid speech involving some words where a vowel follows the /S/ (C2). (14) A phonetic control, which must be used to double-check the vertical dimension of occlusion for the abnormal patient, is to be certain at the try-in that the posterior speaking space measures 1.5 mm, or more (C18). THE FLUIDITY

OF CONTROLS

Using these guidelines, it follows that to avoid contact of teeth at any time during speech and to have clear enunciation, rapid conversation including words involving the /S/-vo\vel sound should be used to develop the proper clearance and eliminate contacts between anterior or posterior teeth.5 Another matter for clarification concerning muscular controls in natural dentitions is that all positions assumed by the mandible during speech are spatial, because no tooth contacts should ever be made. Premature contacts, however, are sometimes built in, resulting in faulty fixed and removable restorative dentistry. Therefore, since the muscles controlling speech are seldom subjected to such traumatic influences, there is no need for change in the muscular movements of speech after teeth

Volume 36 Number 2

Controlling

vertical

dimension

and speech

Fig. 7. The first step is to place upper incisors in harmony with palatal contours, border of the denture, and the anterior vertical /S/ position of the mandibular Fig. 8. S’oft “speaking”

wax is used to determine

classic or atypical

/S/

positions

129

the anterior ridge (CZ). (CZ).

are removed and dentures are placed. This is in contrast to changes which develop in temporomandibular joints as a result of faulty occlusions. In most patients, the classic /S/ position did exist with natural teeth. If it is restored with the anterior artificial teeth and their supporting structures in anatomic harmony with other adjacent structures, the following advantages, besides clear enunciation, are obtained : (1) Developing centric relation requires little judgment, because it is simply an automated retrusion from the /S/ position to a comfortable hinge position and it is repeatedly accurate (Cl 2). (2) Developing the vertical dimension of occlusion (the anterior stop) requires, after retrusion, only a closure of the lower teeth to contact the upper teeth, and this is also an automated, constant, and definite movement (C14) (Fig. 3). Difficulty can exist, however, if the degree of retrusion places the contact of the lower anterior teeth into the palate (C13). The solution to this problem will be covered later (C15, C16, C18). (3) The incisal guide angle is automatically re-established (Fig. 5). (4) The degree of retrusion from the classic /S/ position usually re-establishes the patient’s former class of occlusion (Fig. 6) . In restorative dentistry, either when placing crowns or replacing the upper or lower anterior teeth, the proper /S/ position should be developed at a try-in stage to assure clarity of speech and the esthetic placement of the incisal edges of the restorations. THE FIRST BASIC

PROCEDURE

fCII

Since there is no way to ascertain the former speech patterns and anterior occlusion of edentulous patients during the primary examination, the starting technique is the same for all. Anterior teeth are selected for harmony with the size, form, and color of the

130

Fig. 9. “Speaking” position

J. Prosthet. Dent. Augut. 1976

Pound

is refined

wax is replaced (C8 and CZO)

Fig. 10. The mandible is retruded Class I retrusion is illustrated,

with

two central

incisor

and closed into the contact

teeth, and the clarity of verti-centric

of the /S/

position

(CZ4).

face.” The dentist, using a stabilized base, proceeds with all the skills at his command to place the upper anterior teeth in the simplified manner as previously described (Fig. 7 ) .3* 4, 6 Placing these teeth in the precise location of the patient’s original teeth is not a prerequisite to success. However, their appearance must be pleasing, and their position and length must be in anatomic harmony with the palate and the borders of the base. When this is accomplished, the incisal edges of the central incisors become the spatial control point from which most of the remaining determinations are made in computer-like fashion.

BEGINNING OF AUTOMATION

IC2J

The next step is to place beeswax, called “speaking” ITax, on the anterior portion of a stabilized lower base that has no posterior wax rim, The incisal edge of this wax is adjusted during rapid speech to the classic /S/’ clearance of 1 mm. This is a mechanical procedure, and no judgment is required. It is only necessary to adjust the wax to this clearance and hear the subtle whistle of the /S/ (C2) (Fig. 8). While attempting to do this, the anomalies of speech and anterior occlusion, if they previously existed, become clearly evident, because various nonanatomic and unusable configurations of the speaking wax may develop. Fortunately, it is possible to unite the varied problems and contending principles which arise in such situations, because all their solutions have a common ground based on nonanatomic guidelines. One of the following three basic conditions will become evident when adjusting the speaking wax to the classic /S/ position (C4) : ( 1) In 75 per cent of Caucasians, the classic /S/ clearance will develop with the wax of usable size and angulation (C3). (2) In 20 per cent of these patients, the angulation of the wax or its length will be completely out of anatomic harmony and unusable at the classic /S/ position

iC4).

Volume 36 Number 2

Controlling

Fig. 11. Illustration must be verified

of a Class II retruded

contact.

vertical

dimension

In these patients,

and speech

the verti-centric

131

position

(C15).

(3) In 5 per cent of these patients, it is impossible to develop a normal /S/ clearance or sound because of tongue interference or nerve disorders involving the tongue and other muscular controls (C9). Most patients will present a classic /S/ position with usable wax (C3). With these patients, the wax is replaced with two lower central incisors, and the /S/ space is refined (CIO) (Fig. 9). The degree of mandibular retrusion is then studied, and if this retruded closure places the contact of the central incisors on tooth structure (C12), the automated verti-centric is recorded (CZ4) (Fig. 10). The casts are placed into an articulator. The rests of the teeth are set up to be refined at the try-in (Cl 7), and the dentures can be completed as outlined in the Analytical Control Chart (CZ9) (Fig. 4). ANALYTICAL

APPROACH fC5l

When the development of the classic /S/ position results in unusable wax positions or whenever the retruded contact is on the palatal tissues (Fig. 11) , a different analytical approach must be used. The wax may be too short, it may assume some unusable angle, or it may be too long. The first step is to reconsider the position of the upper teeth; an error might have been made (C.5). If the wax is too short, possibly the upper teeth need to be raised and/or inclined differently. In this way, sufficient height can be developed for the lower wax. The unusable angulation of the wax might dictate the use of a reverse pitch for the upper teeth. If the lower wax is too high, lowering the upper teeth might be all that is necessary. If success is attained by cha.nging the upper teeth and if an anatomic, usable wax length and angle can be developed, the patient will develop the normal classic type of /S/ position, and the denture procedures would be as outlined in C3, that is substituting teeth for wax and re-recording verti-centric and the like. If such corrections are unsuccessful, other means must be employed. In any such patient, including the “no /S/” abnormal type, the speaking wax should be reshaped and set to anatomic harmony (C6). To do this, estimate the amount of bone loss, which could be from 2 to 12 mm., and add to this the assumed length of the patient’s

132

J. l’rortlxt. Dent. AupJzt, IRiO

Pound

lower incisors, which could vary from 5 to 10 mm. An educated guess is made of these combined lengths, and depending largely upon the amount of bone loss, the average might be about 13 mm. This length of wax is then set at a pleasing angle on the crest of the lower ridge. THE ATYPICAL

TYPES

After changing the wax in this manner, the base is placed in the mouth, and again, by utilizing speech, an attempt is made to adjust the length and angulation of the wax to develop the 1 mm. /S/ clearance on the lingual surface of the upper anterior teeth. Usually, this can be done with all of the “short-wax” patients and most of the “angled” ones (C7). To do this, it may be necessary to make minor changes in the inclination and/or improve the lingual anatomy of the upper teeth. These are the atypical patients. Teeth can be substituted for the wax (CS), and the usual automated verti-centric can be successfully recorded (C14). These patients do not have as much forward movement of the mandible as those with the classic /S,/ position. However, if the retrusion produces contact of the wax in the palatal area (CI3) (this can also occur in the patient with the classic /S/ position), such a registration might result in an overclosure of the vertical dimension. When establishing the vertical dimension of occlusion for these patients, it is best to use the one suggested for tongue thrusters (C15). A few of the subjects of the short and poorly angled wax types and all of those of the extra-long wax type will prove to be tongue thrusters or their lower incisors may never have made a contact in occlusion. These patients are also managed in the same manner as tongue thrusters (C9). ABNORMAL

SITUATIONS

“Abnormal” patients are those who have never enunciated a clear /S/ sound with their own teeth. They are of two basic types: real tongue thrusters and patients who lisp. Their most disturbing problems involve speech and occlusion, and these are developed in childhood. During growth, the muscles controlling the mandible compensated for these abnormalities. Such patients continue with these varied patterns whether teeth are present or not. Dentures will function better if they are made to function in harmony with these habits. W’hen developing the /S/ sounds, these patients roll the tongue between the teeth and palate trying to allow just enough space to create the //S/ whistle, which is usually not possible. The replacement of the lower anterior teeth is not as critical as it is, for other patients. The procedure is to set the “speaking” wax to anatomic harmony as previously advised (C6), substitute teeth for the wax (C8), stabilize the base in the mouth, and then adjust the teeth up or down, in or out, until the patient seems to develop a normal fluidity of speech. Also, check appearance ((211) and points where the incisal edges contact in retrusion (C13). If the contact appears usable, record verti-centric as outlined (C15), and at the try-in stage (C18), study both the appearance and the speaking space, both of which can be increased or decreased as deemed necessary. If the degree of retrusion appears excessive and the contact possibly not usable, the suggestions outlined in the section on THE POSTERIOR SPEAKING SPACE (to follow) will be helpful.

Volume 36

Controlling

Number 2

PATIENTS

WHO

vertic.al dimension and .rpeeclr 133

LISP

Patients who lisp are very mild tongue thrusters, On saying /S/ sounds, they utilize only the tip of the tongue, playing along the incisal edges of the palatal surfaces of the upper teeth which creates a sound resembling a leaking valve. Lisping can occur in any type of anterior occlusion, even if the posterior occlusion is perfectly normal. These patients can lisp with no lower teeth at all or with lower teeth in almost any position. They have no true /‘S/’ position, so /S/ sounds cannot be used as a determinant for placing the lower anterior teeth. To determine how to establish their verti-centric, study the degree of forward mandibular movement during speech. This can be done by placing the index finger on the condyle while the patient reads aloud. If no movement or very minor movement is felt, the lower anterior teeth can be set to a Class I or Class III relation and the usual retrusion to contact can be developed ((214). Should the movement of the condyle be gross, a Class II relation will likely result, and the verti-centric should be managed as is done for the tongue thruster (C15, Cl%). THE POSTERIOR

SPEAKING

SPACE

This is the interocclusal space which exists when the patient is speaking rapidly, using words in which the /S/ is followed by a vowel. For the patients who have a classic /‘S/ position, the average speaking space for Class I types is about 1.5 to 3.0 mm.; for Class II occlusions, it is 3 to 6 mm.; but for Class III patients, it is very critical, often little more than 1 mm. The speaking space varies a great deal in those patients having atypical /S/ positions, because it depends upon the degree of their retrusion from the /S/ position to centric contact. Some retrude very little, while those with more than 3 mm. of retrusion usually develop a palatal contact, which always poses a hazard in developing the vertical dimension of occlusion. This difficulty is also present with tongue thrusters and patients who lisp, because there is no definite control for the placement of the lower anterior teeth. Whenever this problem exists, the speaking space can be used as a safety control. While not definitive, it will clearly indicate the greatest and the least amounts of vertical dimension that can be used. The ideal time to resolve these problems is at the try-in (Cl??). A verti-centric record of some type is made and mounted on an articulator. All except the lower posterior teeth are set. A flat block of hard wax is substituted which approximates the expected width and level of the lower teeth. This permits contact of the lingual cusps of the upper teeth to be clearly seen on this flat surface. The dentures are now prepared for a try-in. The bases are placed in the mouth, and the patient is asked to read aloud in the approved manner. By lightly, depressing the corner of the mouth, it is usually easy to determine the amount of space existing posteriorly when the /S/ sounds are used. Since no teeth should contact during speech, at least 1 to 1.5 mm. of space must be present. If contacts are being made, the wax rim must be lowered until at least this amount of space is achieved. This is the control for the greatest vertical dimension of occlusion a patient can have. Other controls for Class II patients and tongue thrusters are based upon judgment involving facial appearance, fluidity of speech. room for the tongue, and the natural use of the musculature ((718).

134

J. I’roathet. Dent. Aup;u\t, 1976

Pound

Usually, the greater the amount of forward movement of the mandible during speech, the greater the required speaking space. In the Cl8 classification, it is often difficult to see the amount of this movement. Usually, this can be ascertained by the method of placing the finger on the condyle, as was previously outlined for patients who lisp. This is also another guideline in determining the class of occlusion and the amount of speaking space needed. The second phase of the safety control is to recognize the minimal vertical dimension of occlusion. If too much speaking space is allowed, it is possible for the lower anterior teeth to contact in the palate when the patient’s jaws are in centric relation. This is not practical and would necessitate either changing these teeth or increasing the vertical dimension of occlusion (Cl 8). COSMETIC

CONSIDERATION

The esthetic controls used in this concept are based upon imitating nature and re-placing teeth in their original positions. However, there are patients who have unpleasant appearance of both teeth and tissues. Most can be helped by orthodontic, operative, and/or surgical means. However, the dentist must always bear in mind that speech, tongue activities, swallowing, and even breathing are influenced, as Ricketts? explains, by faulty tooth positions. Each of these activities must be compensated for when making alterations. In restorative procedures for the prominent maxillae, if the upper teeth, for example, are to be moved upward and backward, which is a common demand, and if the patient had a proper /S/ clearance, this clearance will be altered, because the mandible will continue to carry the lower teeth when enunciating /S/ sounds precisely to their previous positions. Speech will be affected, and a new lower anterior tooth position becomes necessary. Usually, the only solution to maintaining good speech is to move the lower teeth backward and upward. This may be beneficial or it may create other esthetic or tongue problems. For these reasons, studies should have been made previously and the limits of such changes predetermined. Esthetically, some Class III patients present a “bulldog” effect, because their lower incisors are edge-to-edge or are anterior to the upper incisors. The appearance of these patients can be improved without altering speech. The lower teeth can be replaced with fixed or removable restorations which show a less prominent tooth position. This is done by altering the inclination of the lower teeth, but care should be taken to insure that 1 mm. of space for the /S/ clearance remains at the upper incisal edges. To prevent chipping of the incisal edges, which often occurs in Class III occlusions, it is best to use resin lower anterior teeth in the denture. DIAGNOSTIC

DENTURE

VALUES

One of the best methods for analyzing, refining, and confirming clear speech and correct jaw relations for problem patients is to use temporary diagnostic dentures (C19, C20).s These allow progressive refinement of denture details during a period of use, and they incorporate two innovations. The dentures are lined with a resilient, changeable conditioning material which gives immediate tissue comfort, and they have a posterior occlusion utilizing sharp upper cusps opposing a free-running, noninterfering, acrylic resin block used in place of lower posterior teeth (CZ6). These

Vdume

36

Nmnher 2

Controlling

uertirnl

dimension

and speech

135

diagnostic dentures readily permit experimentation with jaw relations and tooth position. They are also a great asset when treating denture patients needing temporomandibular equilibration. Problems can be solved which may appear only after dentures have been worn by the patient (C20). If partial dentures are being constructed, this same procedure can be used for purposes of improving temporomandibular equilibration, appearance, and speech and developing the most practical vertical dimension of occlusion. Extensive experimentation in solving problems with diagnostic dentures has strongly indicated that the vertical dimension of occlusion is a more flexible entity than has been assumed. This is especially true as it relates to patients with Class II occlusions who provide the largest number of problem situations. SUMMARY

In this article, definite ways and means have been discussed for controlling the vertical dimension of occlusion by using certain tooth-to-tooth and tooth-to-tissue relations that exist in normal speech. The primary emphasis is placed on managing the problems encountered in the most troublesome types of patients-those with Class II ccclusions, the tongue thrusters, and those who lisp. It is not easy to identify those patients in whom these problems previously existed after they become edentulous. An Analytical Control Chart has been introduced which can be used to separate these problem patients from the normal ones, and a step-by-step procedure for their management can be followed. Also the phases of this approach which are beneficial in restorative dentistry are reviewed. References 1. Pound, E.: The Mandibular Movements of Speech and Their Seven Related Values, J. PROSTHET. DENT. 16: 835-841, 1966. 2. Pound, E.: Utilizing Speech to Simplify a Personalized Denture Service, J. PROSTHET. DENT. 24: 586-600, 1970. 3. Pound, E., and Murrell, G. A.: An Introduction to Denture Simplification, J. PROSTHET. DEKT. 26: 570-580, 1971. 4. Pound, E., Murrell, G. A., Rieder, C. E., et al.: Computerizing Denture Construction, J. PROSTHET. DENT. 30: 688-693, 1973. 5. Murr~ell, G. A.: Phonetics, Function, and Anterior Occlusion, J. PROSTHET. DENT. 32: 23-31, 1974. 6. Pound, E.: Dentists’ Manual, Anaheim, 1974, Denar Corporation. 7. Ricketts, R. M.: Laminagraphy in the Diagnosis of Temporomandibular Joint Disorders, J. Am. Dent. Assoc. 46: 620-648, 1953. 8. Pound, E.: Preparatory Dentures: A Protective Philosophy, J. PROSTHET. DENT. 15: 5-18, 1965. 32144 AGOURA RD., STE. 204 WESTLAKE VILLAGE, CALIF. 91361