The lateral interocclusal jaw position registration

The lateral interocclusal

jaw position

Clifton T. Moberg, D.D.S. * Oral Roberts University, School of Dentistry,

registration

Tulsa, Okla.

A

lateral checkbite (interocclusal) frame has been designed for use in registering eccentric jaw positions using a tray silicone putty. The advantages of this material are its minimum resistance against closure of the jaws, rapid set, accuracy, resiliency, convenient handling, and trimming to shape. Many dentists, relating casts for diagnostic use. or for construction of dental prostheses, consider efforts to make jaw relationship records as either unnecessary, inaccurate, or too complicated to achieve. The materials and techniques discussed in this study are presented to give dentists rapidly accomplished, accurate ‘techniques for registering the lateral jaw position used in setting the condylar guidances of the articulator to the patient’s individual requirements. Use of this interocclusal frame does not necessitate the need for additional jaw movement writing devices or articulators of any specific design. The setting of various articulators to the lateral interocclusal registrations will be discussed in a subsequent article. DESCRIPTION

OF THE

FRAME

The new frame is 2 mm thick, perfectly rigid, and long enough anteroposteriorly to register the indentations of the teeth bilaterally in the putty (Fig. l).? Made of stainless steel to allow its reuse and sterilization, the frame was designed specifically for use in the first-year occlusion courses at the University of Iowa, College of Dentistry.$ In the icope of dental service afforded by the dentist’s time to register quick and yet accurate interocclusal records, the actual practicality of the service for the patient must be considered. Lateral interocclusal registrations are useful for diagnostic

Presented

at

section, *Associate

Chicago, Professor,

the

American

Prosthodontic

Ill. Department

tTMJ Instrument $A 16 mm motion author.

Co., Santa picture and

398

1979

OCTOBER

Society

table

of Reconstructive Ana, script

VOLUME

Calif. is available

42

NUMBER

clinic

Dentistry. on loan

4

from

the

Fig. 1. The steel tray supports material.

the silicone

putty tray

efforts to understand wear facet patterns and abrasion patterns on incisors and to study the teeth on the cast for interferences not otherwise detectable on mobile teeth. Interocclusal records for limited articulator adjustments are recommended for patients for whom no more than two or three single crowns or a four-unit fixed partial denture are being made. Additional restorative procedures may require more inclusive stereographic, pantographic, or simplex mandibular movement indicator techniques. TECHNIQUE FOR LATERAL INTEROCCLUSAL REGISTRATIONS First the patient is trained to obtain a “border” or ligament restricted jaw movement (centric relation) without the frame in place in the mouth. To obtain this border movement the patient must begin moving the jaw first from the centric relation position. This seats the condyles in the fossae and helps prevent unwanted protrusive jaw movement at the outset. The patient can be trained to manipulate his own jaw in the hingelike opening and closing fashion desired. About 1 inch of jaw opening is maximal, because forward translation of the mandible begins to occur. With the teeth apart, the patient is

0022~3913/79/100398

+ 04$00.40/O

0 1979 The C. V. Mosby

Co.

LATERAL

INTEROCCLLJSAL

JAW

POSITION

REGISTRATION

Fig. 2. Lateral pressure is exerted by the heel of the dentist’s hand to incorporate shift of the mandible.

Fig. 3. The patient closes his mouth relationship.

“straight

up” while

the Bennett

in the canine-to-canine

working

shoulder.” The patient’s head position in the chair does not seem to affect the lateral jaw position procedure, but the position of the dentist’s hands on the patient’s jaw do (Fig. 2). When the patient’s jaw has been moved laterally so that the opposing canines are in a relative edge-to-edge relationship, the patient is asked to “close straight up” (Fig. 3). When this preliminary training is completed, the first actual registration should be taken. Using less than a tablespoon of the silicone putty tray material,* the recommended amount of catalyst is thor-

oughly incorporated for the suggestedmixing time. A well-mixed putty is necessary to assure later convenient trimming of excessmaterial (Fig. 4). The silicone putty tray material is rolled out to a dinch length and divided into two equal parts. One half of the first segment is pressedinto the underside of the quadrant perforated metal and overlapped at the posterior edge onto the top surface (Fig. 5). The side of the putty is pressedand blended at its periphery and covers exposed edges of the frame. The other side of the tray is loaded in the same manner (Fig. 6). The biteframe is carried to the mouth (Fig. 7) with

*Acme,

the rearmost

instructed

Coe

THE JOURNAL

to “move

Laboratories,

your

Chicago,

OF PROSTHETIC

teeth

III.

DENTISTRY

toward

your

left

edges of the putty

situated

at the second

399

MOBERG

Fig. 4. The record is trimmed not narrowed from its original

until only the cusp tip indices remain, but the registration width.

Fig. 5. The tray is loaded prior to its insertion

Fig. 6. Final state of the registration before use. About 45 seconds is allowed to mix and load the material onto the tray. 400

is

into the patient’s mouth.

molar regions. Then the frame’s central crossbar is pressed upward against the maxillary arch until seated and held in place until the other hand can support it by means of thumb and finger pressure against the outside edges of the frame. The dentist now has one free hand and begins directing the mandible into the centric relation position, without actually pressing the teeth into the putty. The jaw is then maneuvered toward the left lateral (border) jaw position with active assistance of the dentist to include the full amount of Bennett shift. This is accomplished by means of a horizontal sideways pressure of the hand against the lateral aspect of the body of the mandible just inferior to the premolar apices. After the jaw has reached the canine-to-canine OCTOBER

1979

VOLUME

42

NUMBER

4

LATERAL

INTEROCCLUSAL

JAW

POSITION

REGISTRATION

Fig. 7. a, The tray is taken to the mouth and b, placed against the maxillary teeth, being supported first by the crossbar and then by the lateral aspect of the sides of the tray. c, After the jaw is in its lateral border position, the,patient closes into the underside putty. d, When adequate closure is made, e, the dentist supports the mandible with opposite finger and thumb pressures to limit any further closure and support the mandibular condyles in their fossae. relationship (estimated by sight because of the intervening frame and putty), the patient is instructed to “close straight up.” During this closure, the lower jaw is still maintained in the border position by the dentist. When the lower teeth have been pressed upward into the putty, the dentist quickly moves both his hands to the jaw-supporting locations (Fig. 7, e). This basic hand support position for making centric relationship records has been described in detail by Dawson.’ For the lateral jaw position the thumbs, touching together at the midline, depress the chin, while the fingers placed along the posteriorinferior borders of the mandible rami elevate the mandible. This mutual, simultaneous interaction of the thumbs and fingers upon the mandible limits further pressing of the teeth into the silicone putty and into contact with the metal in an undesirable manner. At the same time the condyles and the disks are fully seated snugly against both the working-side mandibular fossa and the nonworking articular eminence.

support virtually eliminates this common occurrence and inaccuracy. A lateral interocclusal registration made as described gives a true border movement of the mandible with the assurance that the patient has neither partially protruded the jaw nor allowed the condyles to sublux and “drop away” from the eminences during recording procedures. Lateral interocclusal registrations utilizing the interocclusal frame are of rather limited use in complete denture construction due to the relative ease of displacing the supporting tissue during the firm upward seating pressure. An alternate technique to record lateral jaw positions might be the use of central bearing plates with an injectable recording medium as first introduced by Stansbery.* For other articulation of dentar casts, the use of this rigid frame in making lateral jaw position interocclusal registrations offers the dentist accuracy and convenience for diagnostic analysis and limited restorative procedures.

DISCUSSlON

REFERENCES

The interocclusal space required for the registration is considerably less than that needed for clutches holding a pantograph. Seemingly “oversteep” eminences may be recorded if using wax wafers, since the thickness of the wax tends to sublux unsupported nonworking condyles. The suggested technique of jaw management with the silicone putty and frame THE JOURNAL

OF PROSTHETIC

DENTISTRY

1. 2.

Dawson, P. E.: Occlusal Problems. St. Louis, C. V. Mosby Co., p 56. Stansbery, C. J.: F’unctional position checkbite J Am Dent Assoc l&421, 1929.

1974, The

technique.

Reprint requests to: DR. CLIFTON T. MOBERG 4619 SOUTH HARVARD TULSA, OKLA. 74135

401