Prosthodoníics

Occlusal adjustment by selective grinding and nse of an anteriordéprogrammerTetsuo Saito*

A method of occlusal adjustment that incorporates an anterior déprogrammer was usedin 15 patients with temporomandibular joint dysfunetion and a discrepaney hetweencentric relation and the rnaximal intercuspation position. Temporomandibular joint dys-function was first treated by means of a bite plate, and then the new position of themandible was perpetuated by equilibration aecording to the proposed technique. Thetechnique was found to facilitate selective grinding and provided the patients with easylateral movement of the mandible; gradual control of oeclusai contact, allowing grind-ing to be performed progressively on the balaneing and working sides and in centricposition; and control of the vertical dimension on both sides, obtained through a depro-grammed neuromuscular system. (Quintessence Int 1990;21:887-892.)

Introduction

When selective grinding is used to obtain occlusalequilibrium, skill in prognosticating desirable mor-phofunctional results (occlusal contact relationshipsand occlusal activity related to the lesion') is necessarybecause the goals and procedures are frequently dif-ficult:

1. Moving the mandible laterally {because of a lackof neuromtiscular relaxation)

2. Neuromuscular relaxation in the patient (freedomfrom the signs and symptoms of temporomandi-bular joint [TMJ] dysfunction)

3. Commencing and completing the occlusal adjust-ment in a single operation (which is recommended,because minor adjustments are dangerous, espe-cially in patients with TMJ dysfunction)

4. Adhering to the principles and rules of adjustment5. Analyzing the large number of tape marks on the

occlusal surfaces

To ehminate these difficulties, an occlusal adjust-ment technique that employs an anterior déprogram-mer, similar to thejig described by Lucia,'is proposed.

The proposed technique is not by itself a treatmentfor TMJ disorders. The equilibration will perpetuatethe mandibular position obtained hy treatment witha bite plate.

Method and materials

Fifteen patients presenting with symptoms of TMJdysfunction (headache, pain in the head and face,muscular spasms, nausea, and vertigo) and a discrep-ancy between centric relation (CR) and the maximalintercuspation position (MICP) (Figs 1 and 2) weretreated following the technique outlined below.

University of Sao Patilo, Faculty of Dentistry. Av Prof LucioMartins Rodrigues, Trav 4, Bloco No. 8, Caixa Postal 8216, CEP05508, Sao Paulo, Brazil.

Ca.se report

The casts from one patient, who was representativeof the TMJ dysfunction described above, were mount-ed on the semiadjustabie articulator. The maxillarycast was mounted with a facebow, and the mandibular

Quintesser 11/1990 887

Prosthodontics

Fig 1 Patient with maxillary and mandibular arches in thecentric relation position.

Fig 2 Patient with maxillary and mandibular teeth in themaxima] intercuspation position. There is a discrepancybetween the centric relation (see Fig 1) and maximal in-tercuspation positions {habitual occlusion).

Fig 3 Anterior déprogrammer. A jig-type anterior biteplate (after Lucia )̂ is used as a neuromuseular déprogram-mer' ¡A) horizontal surface (slightly laterally convex); (Bjmark produced on horizontal surface by contact of incisaiedges oí mandibular incisors.

cast was mounted in CR, which was obtained bymeans of an anterior déprogrammer fitted into place3 hours before the registration was made in the waxwafer (Fig 3). The anterior déprogrammer had a near-ly fiat, horizontal surface along the anteroposterioraxis on the lingual side and slightly convex surfaceswhere the incisai edges of the mandibular central in-cisors made contact. Afterward the condylar guidancewas adjusted to 52 degrees on the right side and 55degrees on the left side, and the Bennett angle was setto 12 degrees on the right side and 15 degrees on theleft side.

For the patient whose treatment is being described,occlusal analysis showed that in CR there was pre-mature contact between the maxillary and mandibularfirst and second molars on the right side and greatdisclusion on the left side. In MICP there was contacton all teeth; however, in the articulator, the right con-dyle was shown to discolate from the glenoid fossa.

During lateral movements there were balancing in-terferences, mainly on the right side because of incor-rect occlusal contact among the large amaigam res-torations. This situation was common among the 15patients analyzed in this study. These occiusai factorsmay, in conjunction with emotional stress, result inTMJ disorder syndrome, because of compressioti ofthe innerved and vascular structures of the TMI (disk)and/or stretching of the articular ligaments.

Subsequently, a complete maxillary bite plate wasmade on the articulator in CR by applying the prin-ciples of optimal occlusion.^'' The interferences weredeactivated, allowing occlusal bilateral eontaets si-multaneously in centric relation occlusion position(CRO). Disclusion of the posterior teeth in protrusionwas forced by the construction of an anterior guideon the plate. During excursive lateral movements, thebalancing side was discluded through the constructionof a canine guide on the working side of the plate.These details must be correctly adjusted on each pa-tient.

The patient used the bite plate continuously includ-ing during mastication, thereby inducing correction ofmandibular and condylar positioning in the glenoidfossa and resulting in TMJ stability. The bite platewas adjusted as the mandible repositioned itself. Thisproduced physiologic muscular relaxation as de-scribed by Krogh-Poulsen.'

After 2 weeks the patient was free from the signsand symptoms of TMJ dysfunction through the useof this device.

The mandibular position obtained by the use ofthe

Ouintessence International Volume 21. NumhPr 11/1990

Rrosthodontics

bite plate had to be perpetuated by equilibration. Thediagnostic adjustment was first made on the casts andthen on the patient using four differently eolored rib-hons:

1. Red: centric stops2. Black: protrusive interferences3. Green: working side interferences4. Blue: balancing side interferences

To begin the adjustment, the complete bite plate wasremoved, and grinding was performed to correct fheinterferences in protrusive movements, applying themethods of Stuart. All protrusive and lateral interfer-ences were removed first and then the remaining in-terfering contacts in centric relation were attended to,hecause this was the only phase in which occlusal ad-justment was made without the anterior déprogram-mer in place (Stuart CE: Personal communication.1973). The other adjustments were then made with theanterior déprogrammer fitted into place.

Initially, the patient was asked to touch the hori-zontal surface and perform lateral movement.̂ . If nocontact occurred between the posterior teeth duringthe lateral movements then the horizontal surface onthe anterior déprogrammer was ground until the pa-lient indicated when the first lateral posterior inter-ference was felt. If the first interferences were foundon the balancing side, blue ribbon was used to markthese interferences. The anterior déprogrammer wasthen removed and red ribbon was placed in positionto mark CR contacts, using the technique describedby Dawson.''

After the anterior déprogrammer was placed again,grinding of the blue marks on the balancing grooveof the stamp cusps was begun on the balancing side,while the red centric relation contact marks were leftin place (Figs 4 to 8).

After those interferences had been removed, the hor-izontal surface of the anterior déprogrammer was re-ground and refitted into position, and the mandiblewas moved lateraüy. If the working side touched, theinterferences (green marks) were then ground accord-ing to the BULL rules,* while the red centric contactsand cusp guide were maintained (Fig 9). Thus, suc-

' Schuyler's BtJLL rule: The BULL rule applies to the correclionof interferences during luleral movemenis (correction will be car-ried out on the Buccal cusps ofUpper teeth and Ihe Lingual cuspsof Lower teeLhl.^

Fig 4 With déprogrammer in position, colored ribbon isplaced between fhe ma>!iilary and mandibuiar posteriorteefh on the side on which interferences are indicated.

Fig 5 Study casts mounted in articulator showing interfer-ences on balancing side.

Fig 6 Absence of confact on ieft working side is causedby interference on the rigfit baiancing side.

Qu i ntessepc" ''P's'' airj^ur

Prosthodontics

Fig 7 Interferences on balancing side on the maxillarysecond and third molars.

Fig 8 Interferences on balancing side on the mandibularsecond and third molars.

Fig 9 Interferences on working side (green marks). Notethe appearance of centric contacts (red marks).

cessive grinding steps were performed both on the fiathorizontal surface of the anterior déprogrammer andon the interferences that became progressively visible

on the teelh, until the CR contacts began to appearwith the deprogramtner still in place.

The final stage was the adjustment of the centricrelation. The equilibration, tnade with the help of theanterior déprogrammer, gave the patient a nenrophy-siologically stable centric relation position. Red mark-ing ribbon was placed between the maxillary and man-dibular posterior teeth while the rnandihle was heldneurornuscularly by the anterior deprogratnmer. If ttis difficult to hold the mandible tn CR. then theDawson" technique ts applied, with the déprogrammerin position, to acquire the desired result.

The Schuyler* and Jankelson' rules were applied togrind the premature contacts until simultaneous bi-lateral contacts were obtained, which stabilized themandible in position with coincidence of CR and CC)(centric relation occlusion), and transmitted the pres-sure axially (Figs 10 to 13).

Schuyler's rule to correct interfering tooth contacts in CR: Onlycorrect a cusp tip if it interferes not only in centric relation butalso in lateral and protrusive movements. If ttiis is not tiie case,then always deepen the opposing fossa.Jankelson's rule: "Lateral slope.s should be relieved by narrowingthe interfering areas to point or line contaci rather than reducingthem bodily. This will sharpen them into cutting edges or pointsiind reduce (he contacting arca."^

890 Quintessence International Volume 21, Number 11/1990

Prosthodontics

Fig 10 Bilateral, simultaneous, centric contact marks onmaxillary teetti obtained with and without déprogrammerplaced in position.

Fig 11 Bilateral, simultaneous, centric contact marks onmandibular teeth obtained witti and without déprogrammerplaced in position.

Fig 12 Maxillary and mandibular tcoth in maximal inter-cuspation position coinciding with ttie centric relation po-sition obtained witti déprogrammer fitted (CRO].

Fig 13 Maxillary and mandibular teeth m maximal inter-cuspation position coinciding with the centric relation po-sition obtained without the déprogrammer fitted.

Results and discussion

Two weeks after the first adjustments, patients contin-ued to show relief from the symptotns and signs ofTMJ dysfitnctiun.

The horizontal flat surface of the anterior dépro-grammer heiped position the mandible in CR and al-lowed easy performance of lateral movements. It alsogradually revealed the interferences, facilitating thetrvisibility, localizatton, and progressive grinding.

The occlusal adjustment must be performed wtththe condyle in the correct neuromuscular (physiolog-ically) position in the glenoid fossa in CRO. The an-terior déprogrammer permitted both centric and lat-eral adjustments (on both the working and balanctng

sides) and allowed the neuromuscular system to reac-quirc final coordination. This is an advantage over theother currently employed techniques, which are ap-plied only in centric adjustments, such as the leaf-gauge technique described by Long.'

Conclusion

Chnical experience in 15 patients showed that occlusaladjustment by selective grinding in conjunction withan anterior déprogrammer permitted:

1, Facility of mandibular movement2. Control of occlusal contacts, which appeared grad-

Quintessenee-ifllornationoi sJumber 11/1990 891

Prosthodontics

ually, permitting progressive adjustment on the bal-ancing and working sides and in CR

3. Control of vertical dimension of both sides, ob-tained through the deprogramming of the neuro-muscuiar system.

References

t. Walker PM, Cünuitlc DC: Oœlusal adjiistnionl by selectivegrinding i & 11, m ingriiliíun R (ed); Physiology of Occiusioti:Laboratory Mam/a!, Los Angeles, University of Southern Cali-fornia School of Dentistry. 1972, pp 97-106.

2, Lucia VO; Modern Gnuthologicat Concepts—Updated. Chicago,Quintessence Publ Co, 1983. p 439.

3. Beyron H: Optimal occlusion. Dent din Nwtli .'im 1969:13:537-554.

4. Dawson PE: Evaliiution, Diagnosis and Tn-aiment of Occima!Proi>!ems. St Louis, CV Mosby, 1974. p 407.

5. Krogh-Poulsen W: The significance of occlusion in temporo-mandibnlar function and dysfunction, in Solberg WK, Clark GT(eds): Temporumandibuiar Joint Probteiiis: Biologic Diagnosis andTreatnieni. Chicago, Quintessence Publ Co, ISBO, pp 93-110.

6. Schuylcr CH: Fundamenlal principles in correcting of occlusajdisharmony, nalural and arlillcial. ./ Am Dent A.i.yoc 1935;22:1193.

7. Jankelsoii B: A technique lor obtaining optimum functionalrelationship for naltir.il dentition. Dent CItn North Ant 1960;March: 131-141.

8. Long JH: Locating centric relation with a left gauge, J Pro.tiiieiDent I973;29:6O8-6IU. D

Books on

Prosthodontics

Fundamentals of Tooth Preparationsfor Cast Metal and Porcelain RestorationsH. T Shilljngburg, Jr/R. Jacobi/S. Brackett

Won ttie medicat tiooi< awardfrom ttie American MedicatWriters Association.

"The only book devoted exclusively to proper preparation techniques. "

Covers preparation techniques for all types of cast metal and porcelain restorations. Each step is covered inminute detail. Accurate diagnosis, thoughtful treatment planning, and the matching of preparation designsto patient needs are stressed.

Contents: l. Biomechanical Principles of Preparations; 2. Fini.ih Lines and the Periodontium; 3. Instrumentation; 4. Full Veneer Crcnvns;5. Maxillary Posterior Three-Quarler Crowns; 6. Mandibular Po.steriorThree-Quarter Crowns; 7. Anterior Three-Qu arter Crowns; 8, Pin-Modified Three-Quarter Croivns; Q. Seven-Eighlhs Crowns; 10. Proximal Half-Crowns; 11, Inlays; 12, MOD Onlays; 13, Anterior Porcelain-Fused-to-Metal Crowns; 14. Posterior Porcelain-Fused-to-Metal Crowns; 15. All-Ceramic Croivns; 16. Preparation Modifications forDamaged Teeth; 17. Preparation Modifications for Special Situations.

390 pp/fl76 illus (e37 Ln tolor)/S78/Codei 1579

An Atlas of Removable Partial Denture DesignR. J. Stratton/F. J. Wiebelt

"Helps you quickly and accurately arrive at the best design. "

Presents a giant step forward in the often frustrating and confusing subj ect of removable partial denture design.Part I provides sound rules of design. Part II—a unique atlas—shou's designs for over 250 of the most commonpartially edentulous arches. Clinically applicable reference book for dentists, students, and dental techniciansthat will provide hetter patient care and can be an excellent communication tool.

Contents: Par! I, Design Concepls. 1. Surveying; 2. Rests; 3. Guide Surfaces and Guide Plates; 4, Major Connectors; 5, Minor Connectors;6. Retention and Relainers; 7. Denture Base Retentive Elements; 8. Replacement Teeth; 9. Mouth Preparation. Par! II, Atlas coversmandibular and maxillary Class I through V designs.

335 pp/Bno iilus/S4B/Code: 1900