Craniomandibular Function and Dysfunction: Leaf Gauge [PDF]

Zitiervorschau

CRANIOMANDIBULAR SECTION

GEORGE

FUNCTION

AND DYSFUNCTION

EDITOR

A. ZARB

Simple application of anterior routine clinical practice W. J. Carroll,

D.D.S.,’

The Ohio State University,

J. B. Woelfel,

D.D.S.,**

College of Dentistry,

Columbus,

S

and R. W. Huffman,

THE JOURNAL

OF PROSTHETIC

DENTISTRY

D.D.S.*‘*

Ohio

everal sophisticated articulating instruments have been developed’-) and are used to study various aspects of jaw movement and tooth contacts.“” Most restorations are made in centric occlusion, not centric relation occlusion. More information is needed in regard to anterior coupling,“-” the relationship of malocclusion to immediate side shift canine-protected and group-function occlusal relationships,‘5-‘7 and the speculated relationship of malocclusion to the progression of periodontal disease.” Williamson’8.‘9 defined centric relation as “a position in which both mandibular condyles are simultaneously seated most superiorly on the posterior slopes of the articular eminences, with the menisci interposed properly between.” The patient’s own healthy closing muscles, contracting evenly on both sides, can best direct the mandible into centric relation. A terminal hinge arc of closure occurs only under certain conditions: dentist manipulation, neuromuscularly relaxed and trained patient, or when a patient closes properly onto a leaf gaugem or an anterior jig21e2’(Figs. 1 and 2). The significance and advantages of being able to place the mandibular condyles into the centric relation position are as follows: 1. Centric relation is usually an easily reproducible and not uncomfortable position. 2. When the condyles are retruded, the mandible is capable of repeatedly making a purely rotational movement through an incisor separation of 10 to 25 mm,15.24 permitting location and transfer of this axis to an articulator. 3. Patients appear to function comfortably in centric relation after .a centric relation occlusal equilibration, after a full-mouth rehabilitation, during occlusal splint therapy, and in wearing complete dentures. 4. Numerou.s temporomandibular joint disturbances including pathologic changes may occur or are triggered when malocclusion exists because of tooth movement, dental restorations, or inadequate orthodontic treatment 12.13. IS.25

*Private practice, Pcrrysburg, Ohio. **Professor. Department of Restorative and Prosthetic Dentistry. ‘**Professor Emeritus, Department of Restorative Dentistry,

jig or leaf gauge in

5. Patients with painful temporomandibular joints frequently report surprisingly quick relief of their pain and other symptoms after either wearing an occlusal splint, biting on a leaf gauge (Fig. 1) for several minutes, or after a dentist has removed the tooth or teeth that were prematurely contacting in the centric relation position.2s.’ For a number of years the anterior jig2’-” (Fig. 2) and more recently the leaf gauge20*27-m have been shown to be reliable methods for consistently placing and securing the condyles in a centric relation position.‘9 Both maintain the minimal increased vertical dimension necessary to negate tooth contact. This article acquaints or reminds the reader of characteristics, principles, fabrication, and valuable clinical applications of an anterior jig and of a leaf gauge. ANTERIOR

JIG CHARACTERISTICS

The anterior jig (Fig. 2) is quickly made of autopolymerized acrylic resin and is therefore rigid.2’.22 It can be made directly in the mouth or on a maxillary cast. The jig covers the maxillary central incisors and a small area of the palate with minimal internal spacing. Its outer surface is adjusted so that a lower central incisor contacts the smooth lingual incline of the jig at only one point. The jig’s incline must stop the closure of the mandible before posterior tooth contact, and this lingual slope should be angled 45 to 60 degrees posteriorly and superiorly from the occlusal plane (Fig. 2). PRINCIPLES The anterior jig (or appropriate thickness of a leaf gauge) prevents the posterior teeth from occluding and, in so doing, appears to modify proprioceptive memory.5,‘9 Because the anterior jig (or leaf gauge) is rigid, once it is contacted by the lower incisor on retruded closure, anterior resistance is created (Fig. 3, right) and the leverage of the mandible is reversed, creating a naturally braced tripod effect with the two condyles (Fig. 3).3’-” Contrast the reversal of the class III lever situation

l McHorris

WH. Gnathologic Ohio, April 25, 1985.

conference presentation. Columbus,

611

CARROLL,

WOELFEL,

AND

HUFFMAN

Fig. 1. Above, left, Patient with head reclined to stretch neck muscles while she closes on a numbered leaf gauge. Below, left, Close-up shows leaf gauge producing minimal separation of teeth as it creates anterior resistance (see Fig. 3, right). Above, right,

Numbered plastic leaf gauge. Each leaf is approximately 0.1 mm thick; 55 leaves together as seen below create an incisal separation of 5.2 mm. Below, right, Side view of numbered leaf gauge with all 55 leaves stacked and held together

that occurs when a patient chews food or bites into an elevated anterior stop preventing further closure (Fig. 3). As the jig or leaf gauge is engaged by the lower incisors with the closing muscles continuing to contract, the condyles are more likely to become seated in their middle and most superior positions.‘9*2* It has been suggested that protrusion is avoided because a natural reflex prevents contraction of the lateral pterygoid muscles as the patient bites firmly on a leaf gauge.“,” CHAIRSIDE ANTERIOR

FABRICATION JIGZ’

OF AN

1. The patient is positioned in the dental chair with the head tipped backward at an angle of approximately 45 degrees to stretch the neck muscles, fascia, and skin (Fig. l).z8,29 2. The patient is instructed to move the chin forward and back several times with the teeth apart and, finally, to close slowly. 3. The dentist’s thumb is held gently against the 612

by plastic rivit.

patient’s chin. The patient is instructed to push the jaw forward and then backward as the dentist provides gentle posterior guidance and decides by his own tactile sensation whether the condyles are seating in the glenoid fossa:19,23,26,28,29The dentist’s index and middle fingers should be placed under the lower border of the mandible near the angle to support the mandible in an upward direction.30s3’ 4. Doughy acrylic resin is molded over the maxillary central incisors and the patient is asked to direct the chin forward, then back, and then to close slowly until you say “Stop” (jaw closure into the soft acrylic jig is stopped 3 or 4 mm short of occlusal contact). As the material stiffens it can be removed and placed in water to dissipate the heat.

5. Once the acrylic resin dough has hardened, the indentations of the lower anterior teeth are ground away so that the lingual surface of the jig becomes smooth and slopes in an upward posterior direction from the occlusal plane (Fig. 2). MAY

1988

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5

APPLICATION

01: ANTERIOR

JIG OR LEAF GAUGE

Fig. 2. Above, left, Incisal view of Lucia jigzl sufficiently narrow so it covers parts of both central incisors. It is thickest only on lingual at midline to produce desired jaw separation. Rest of smooth lingual portion thins to a featheredge toward distal of each upper central incisor. Below, left, Labial view of Lucia jig adjusted to produce desired minimal degree of jaw opening to separate all teeth. Mandibular incisor contacts a smooth lingual incline that guides mandible superiorly and posteriorly as patient taps or closes firmly. Above, right, Close-up semiside view indicates upward slope of lingual surface that creates desired anterior resistance. Below, right, Side view of acrylic resin jig showing its bulk and angle of important lingual surface.

6. Whenever the jig is removed from the mouth, the patient is asked to bite on a cotton roll or leaf gauge, or a saliva ejector is placed in the mouth to keep the teeth apart. This will maintain the deprogramming of the adaptive mandibular closure path (engram).5*‘9 Your instructions to the patient at this time should be “Chin out and back, and close” (onto the cotton roll, leaf gauge, or saliva ejector). 7. Once properly shaped, the jig is replaced in the mouth. The patient is asked to close in a retruded position on the jig for a minute or two to allow for further muscular relaxation and concomitant repositioning of the mandibular posture to continue. The retruded tooth contact on the jig is marked with a thin Mylar-type (DuPont Co., Wilmington, Del.) articulating tape. Instructions to the patient for this procedure should be, “Chin forward and back, (Mylar tape is inserted), now close in the back and tap together several times on this jig.” 8. Completion of the jig is done by removing extraneous contacts other than the only one centered lower incisor mark that remains, and this small spot of contact is reduced until the desired vertical dimension of occlusion is reached (minimal opening but an assured separation of all opposing teeth). THE JOURNAL

OF PROSTHETIC

DENTISTRY

APPLICATIONS

OF PLASTIC

ANTERIOR

JIG

The plastic anterior jig is used routinely in two clinical situations. It is often used in the fabrication of maxillary centric relation biteplanes or splints. After fabrication of a vacuum-formed plastic material onto a maxillary stone cast, an anterior jig is added to the splint covering the incisive papilla region. It is then adjusted to the desired minimally opened vertical dimension before the addition of ropes of acrylic resin over the entire occlusal and incisal area, including the jig.15a30 The anterior jig is frequently used to make accurate centric relation jaw records (Fig. 4, above), providing the muscles of mastication have relaxed before the registration. The anterior jig guides and stops the retruded mandibular closure arc at the preselected vertical dimension as the recording medium (zinc oxide and eugenol, polyether,

wax, acrylic

resin, or plaster)

is interposed

between the posterior teeth. ALTERNATIVE METHODS ADAPTIVE MANDIBULAR PATTERNS, l9

FOR AVOIDING CLOSURE

Several other methods can be used to assist the dentist

and patient in recording the terminal hinge position of the mandible: 613

CARROLL,

THE MANDIBLE ASA CLASS III LEVER

WOELFEL,

AND

HUFFMAN

THE MANDIBLE ASA REVERSE CLASS III LEVER

Fig. 3. Top, Class III lever diagram. Below, left, Mandible. as it normally functions in mastication. Below, right, Reversal of normal class III lever that is created by anterior resistance such as a Lucia jig, leaf gauge, thin strip of metal, or as incising a carrot.

1. Central bearing screw and opposing table or inclines (gnathological clutches) used with pantographic tracings of mandibular border movements 2. Narrow strip of x-ray foil or relief chamber metal over the upper incisors32~3’ 3. Impression compound or hard wax anterior stop” 4. Biting on a saliva ejector, cotton roll, or popsicle stick” 5. Sliding the teeth with a credit card interposed between them” 6. Patient relaxation with concomitant dentist manipulation of the mandibleQ 23.25 7. Use of a leaf gaugp31-35*36

Perhaps the most useful and practical alternative to the anterior jig is the leaf gauge.~27-B~3*The leaf gauge (Fig. 1, right), similar to a “feeler gauge,” consists of multiple sheets of plastic, one or more of which is placed between the incisors at an upward angle. The dentist can then create anterior resistance at any vertical dimension by the addition or removal of leaves (Fig. 3). Previously, some leaf gauges were made from unexposed panoramic x-ray film, which was developed to remove the emulsion coating, thus providing a clear film. The film was then cut into 1 cm X 5 cm sections and bound together by some type of screw-post fasteners. Recently, a more sophisticated leaf gauge was described.35pXIt is made out of a thinner, more pliable plastic. The leaves are a uniform 0.1 mm thick and sequentially numbered to provide a convenient measure 614

and record of exact vertical opening between the incisors (Fig. 1, right). Narrow more firm paper disposable leaf gauges were described by Woelfel.3’ The leaf gauge is frequently used to obtain diagnostic centric relation interocclusal records (Fig. 4, belqw), to test for existing undetected prematurities”*29 when performing an occlusal equilibration, and when fitting and adjusting cast restorations before their cementation.* The leaf gauge may also be used periodically by the patient as prescribed by the dentist to relieve painful spasms of the lateral pterygoid muscles.‘9~3’,’The leaf gauge is a valuable yet simple device. The general dental practitioner can incorporate it routinely into treatment procedures that enhance the quality of professional services to the patient. In February 1985, the Committee on Scientific Investigation of the American Academy of Restorative Dentistry commented as follows: “The leaf gauge seems to have gained renewed popularity as a diagnostic aid, occlusal adjustment aid, and has been shown to be helpful in securing centric relation interocclusal registrations.“*’

l McHorris

WH. Gnathological confcrcncc prcscntation. Columbus, Ohio, April 25, 1985. MAY

1988

VOLUME

59

NUMBER

5

APPLICATION

OF ANTERIOR

JIG OR LEAF GAUGE

:Fig. 4. Above, Zinc oxide-eugenol interocclusal record supported by fiberglass formulator mesh (wire frame has been removed) with Lucia jig directing mandible posteriorly and maintaining desired degree of vertical separation of teeth. This type of centric relation record is used when accuracy is paramount. Notch for jig is seen right. Below left, Aluwax cloth wafer checkbite is being made with leaf gauge to direct mandible and maintain vertical dimension. This type of centric relation record is often used for diagnostic mountings. Notch in wax record accommodates leaf gauge (right).

APPLICATIONS

OF THE LEAF GAUGE

The leaf gauge is held by the dentist or assistant with an arbitrary number of leaves placed in the oral cavity at the maxillary anterior midline parallel to the lingual plane of the maxillary central incisors (Fig. 1, left). The patient is instructed to close on the back teeth until a lower incisor touches the underside of the leaf gauge. Leaves are added or subtracted as required until the patient can just barely feel a posterior tooth touch while

closing firmly on the leaf gauge. With the addition of a single leaf the patient initially should not feel any posterior tooth contact. As the jaw is held closed with a “half-hard” closing force for approximately 15 to 20 seconds, often the patient again w:ill be able to feel a posterior tooth contact. The dentist must then add a leaf and the procedure is repeated. Leaves are added one at a time until the patient can close with a half-hard closure force for 2 to 5 minutes without feeling any posterior tooth contact. At this time the mandible is “tripodized.“32+33,37,3*in its centric relation position with the right and left condyles THE JOURNAL

OF PROSTHETIC

DENTISTRY

seated in their respective fossae, and with the lower incisors contacting on the underside of the leaves which slope posteriorly upward. We presume that using a leaf gauge in this manner eliminates potential operator-guided errors in centric relation by permitting the patient’s own neuromusculature to seat the condyles in their centric relation posi-

tions. The average number of additional leaves that must be added to arrive at this final position is six, with a normal range from one to nine.

If the leaf gauge is being used for an occlusal equilibration or to adjust castings to centric relation occlusion, the procedure is begun with the mandible in the tripodized centric relation position6x34 as just described. Leaves are gradually removed, one at a time, the prematurity is marked each time with Mylar tape and the necessary adjustments are made as each leaf is removed. A significant advantage is that the patient is more conscious of biting or tapping on the centrally located leaf gauge than on the unilaterally placed articulating

film, thus avoiding

the prematurity.

615

CARROLL,

When using the leaf gauge to make centric relation interocclusal records (Fig. 4) for mounting diagnostic casts, the dentist also starts with the mandible in the tripodized centric relation position32s33,37,38and arbitrarily adds three or four additional leaves to assure that the teeth cannot close completely through the recording material (which would result in an inaccurate record). An anterior cutout is made in the recording-material carrier for the leaf gauge (Fig. 4, below right). The recording material is positioned onto the maxillary arch of teeth, the leaf gauge is properly inserted, and the patient is instructed to close on the back teeth as before until a mandibular incisor touches the leaf gauge. The patient then gently, but firmly, holds the mandible in this position until the recording material chills or sets. A recently introduced system uses a carrying wafer with an incorporated slot for the leaf gauge.” Regenos* uses the leaf gauge exclusively when fitting and adjusting multiple castings before cementation. Previously, he remounted the casts to finalize the gold occlusal contacts on the articulator and found this to be a time-consuming and potentially an inaccurate procedure. In the leaf gauge procedure, the chairside assistant positions the leaf gauge and one-side articulating film or wax while the dentist, holding the articulating film or wax on the other side, instructs the patient to concentrate and close or tap on the leaf gauge. In this manner the patient is not tempted to bite toward the side of the tooth to be marked. This method avoids any previous adaptive closure patterns by the patient.5s’9

SUMMARY Utilization of either of the two described methods by dentists is recommended as a simple means to routinely record or provide centric relation closures. The leaf gauge (1 to 6 mm thick) can be made from plastic or x-ray film or it can be purchased. The anterior acrylic resin jig can be made in a few minutes directly in the mouth by the dentist or an assistant or by a technician using mounted casts. Both methods avoid adaptive mandibular closure patterns and dentist-guided jaw closure as well as other commonly unrecognized errors in assessing occlusal contacts.

4.

5.

6.

7.

8. 9.

10.

11.

12.

13. 14. 15. 16.

17. 18.

19.

20. 21. 22. 23. 24. 25.

*Regenos J, Wilkes R. Personal communication, Nov. 1984, Cincinnati, Ohio.

REFERENCES 1. 2. 3.

Ring ME. Dentistry. An illustrated history. 1st ed. St Lquis: The CV Mosby Co, 1970;307-10. McCollum BB, Stuart CE. A research report. Ventura, Calif: Charles E. Sturat, DDS, 1955;62-86. McCollum BB. The mandibular hinge axis and a method of locating it. J PR~~THETDENT 1960;10:428-35.

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28. 29.

WOELFEL,

AND

HUFFMAN

Gibbs CH, Derda HJ. A new articulator emphasizing centric occlusion and the anterior determinants. J PROSTHETDENT 1977;37:382-93. Lundeen HC, Shryock EF, Gibbs CH. An evaluation of mandibular border movements: their character and significance. J PROSTHETDENT 1978;40:442-52. Gibbs CH, Lundeen HC, Mahan PE, Fujimoto J. Chewing movements at the first molar. J PR~~THETDENT 1981;46:30822. Clayton JA, Crispin BJ, Shields MJ, Myers GE. A pantographic reproducibility index (PRI) for detection of TM J dysfunction [Abstract]. J Dent Res 1976;55: Beard CC, Clayton JA. Effects of occlusal splint therapy on TMJ dysfunction. J PR~~THET DENT 1980;44:324-35. Shotwell JL, Kotowicz WE, Clayton JA. Ability of edentulous subjects to reproduce mandibular border tracings. J PR~STHET DENT 1980;44:379-83. Jankelson B, Swain CW, Crane PF, Radke JC. Kinesiometric instrumentation: a new technology. J Am Dent Assoc 1975; 90:834-43. Jankelson B. Measurement accuracy of the mandibular kinesiograph-a computerized study. J PROSTHETDENT 1980;44:65666. McHorris WH. Occlusion with particular emphasis on the functional and parafunctional role of anterior teeth; part 1. J Clin Orthod 1979;13:606. Brose MO, Tanquist RA. The influence of anterior coupling on mandibular movement. J PROSTHETDENT 1987;57:345-53. Schwartz H. Occlusal variations for reconstructing the natural dentition. J PROSTHETDENT 1986;55:101-5. Woelfel JB. Dental anatomy; its correlation with dental health service. 3rd ed. Philadelphia: Lea & Febiger, 1984;348-65. O’Leary TJ, Shanley DB, Drake RB. Tooth mobility in cuspid-protected and group-function occlusions. J PR~~THET DENT 1972;27:21-5. Goldstein GR. The relationship of canine-protected occlusion to a periodontal index. J PR~~THET DENT 1979;41:277-83. Williamson EH. Dr. Eugene H. Williamson on occlusion and TMJ dysfunction (interview by S Brandt). J Clin Orthod 1981;15:333-50. Williamson EH. The role of craniomandibular dysfunction in orthodontic diagnosis and treatment planning. Dent Clin North Am 1983;27:541-60. Long JH. Locating centric relation with a leaf gauge. J PROSTHET DENT 1973;29:608-10. Lucia VO. A technique for recording centric relation. J PROSTHETDENT 1964;114:492-505. Wise MD. Occlusion and restorative dentistry for the general practitioner. London: British Dental Association, 1982;14-6. Dawson PE. Evaluation, diagnosis, and treatment of occlusal problems. 1st ed. St Louis: The CV Mosby Co, 1974;48-70. Possclt U. The physiology of occlusion and rehabilitation. Philadelphia: FA Davis Co, 1962;40-8. Roth RH, Rolfs DA. Functional occlusion for the orthodontistPart II. J Clin Orthod 1981;15:100-23. Guichet NF. Biologic laws governing functions of muscles that move the mandible. Part II. condylar position. J PROSTHET DENT 1977;38:35-41. Phillips RW, Hamilton IA, Jendresen MD, McHorris WH, Schallhorn RG. Report of the Committee on Investigation of the American Academy of Restorative Dentistry. J PROSTHETDENT 1985;53:844-70. Golsen LF, Shaw AF. Use of leaf gauge in diagnosis and therapy. Qunitessence Int 1984;6:61 l-21. Shankland WE, Ralston SJ. The fabrication and use of a leaf gauge to locate centric relation. Ohio Dent J 1983;57:43-5. MAY

1988

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NUMBER

5

APPLICATION

OF ANTERIOR

JIG OR LEAF GAUGE

30.

Huffman RW, Regenos JW. Principles of occlusion laboratory and clinical teaching manual. 8th ed. Columbus: H and R Press, 1980;VI-A-27. 31. Woclfel JB. A new device for accurately recording centric relation. J PROSTHETDENT 1987;58:716-27. 32. Wirth CG, Aplin AW. An improved interocclusal record for centric relation. J PROSTHETDENT 1971;25:279-85. 33. Kornfield M. Mouth rehabilitation clinical and laboratory procedures. 2nd ed. St Louis: The CV Mosby Co, 1973;14-7. 34. Strohaver RA. A comparison of articulator mountings made with centric relation and myocentric position records. J PROSTHET DENT 1972;28:379-90. 35. Rosenblum RH, Huffman RW. Leaf gauge with consecutively

36. 37. 38.

numbered leaves. J PR~STHET DENT 1985;54:652-4. Huffman R. A numbered leaf gauge (instruction booklet). Columbus: Huffman Leaf Gauges, 1984. McHorris WH. Occlusal adjustment via selective cutting of natural teeth. Part I. Int J Perio Rest Dent 1985;5:9-25. McHorris WH. Occlusal adjustment via selective cutting of natural teeth. Part II. Int J Perio Rest Dent 1985;6:9-29.

Reprmt requeststo: DR. JULIAN B. WOELFEL THE OHIO STATE UNIVERSITY COLLEGE OF DENTISTRY COLUMBUS, OH 43210

Frontal chewing patterns of the incisor point and their dependence on resistance of food and type of occlusion P. Priischel, Dr.Rer.Nat.,* and M. Hofmann, Prof.Dr.Med.Dent.** Friedrich Alexander UniversitHt, Poliklinik

fiir Zahnirztliche

lhe concern of dental scientists with the recording of masticatory movements is an outgrowth of the conviction that such research would aid in the diagnosis of functional disorders of the stomatognathic system. Nevertheless, reports on normal physiologic mastication have revealed large interindividual variations and a multitude of different chewing patterns.’ In the absence of systematic methods of classification, only the most commonly observed forms of movements have been described and the use of different nonstandardized test foods often led to contradictory statements. This study used a newly developed procedure for chewing-pattern classification.2s3 This provided numerical data on frequencies of the patterns of normal chewing and their dependence on the consistency of food and type of occlusion.

METHODS Chewing movements of the incisor point of the lower jaw were recorded by using a Sirognathograph instrument (Siemens Corp., Bensheim, West Germany) and further processed by a connected computer system (Hewlett Packard Co., Palo Alto, Calif.). The accuracy and linearity of the electrognathographic method have been tested by several researchers, with an accuracy of 1% achieved in the spatial domain to which chewing *Akademischer Rat, Department of Prosthetic Dentistry. **Professor, Director of the Department of Prosthetic Dentistry. THE JOURNAL

OF PROSTHETIC

DENTISTRY

Prothetik, Erlangen, West Germany

movements are confined.5s6 Two patient groups were studied. One group comprised of 193 young adults (148 men and 45 women in the age range of 21 to 33 years; mean age 26 years) was randomly chosen. Criteria for inclusion in this study included (1) complete dentition in both jaws, no tooth loss except, occasionally, missing third molars, (2) no dental complaints or functional disorders, (3) no clinically detectable pathologic findings, and (4) no severe dysgnathia requiring treatment. This group of test subjects is referred to as the normal group or normal sample. In the second test group, 41 patients (20 men and 21 women in the age range of 16 to 38 years; mean age of 24 years) with mandibular prognathism were studied. Winegum and equally sized pieces of soft bread without crust were assigned as tough and soft consistency test food. With each kind of bolus, one trial with chewing on the right and one with chewing on the left side were registered. Starting from the habitual intercuspal position, each chewing action was recorded over a period of 20 seconds.

EVALUATION Evaluation of the data included the classification of chewing patterns and the calculation of parameters describing the temporal and spatial behavior of the masticatory movements. This procedure, which has been successfully applied23’ includes the following. 617