Influence of tooth contact on the path of condylar movements

SECTIONEDITOR

Influence

of tooth

contact

on the path of condylar

movements

M. M. Alsawaf, DDS, MS,* and D. A. Garlapo, DDS,b State University of New York at Buffalo, School of Dental Medicine, Buffalo, N.Y. The correlation between condylar inclination and tooth guidance was tested by comparison of recordings of condylar movement in right and left parasagittal planes during lateral excursion, opening, and protrusive movements in 13 subjects with temporomandibular joint (TMJ) clicks and 15 subjects without TMJ clicks. The characteristic tracing of mandibular movements at the condyle with toothguided versus non-tooth-guided conditions were investigated by use of a computerized Axiograph graph. The generated tracings of each subject were graphed and analyzed to calculate the horizontal condylar inclinations as related to the axis orbital reference plane. Information from a standardized questionnaire provided evidence of a definite correlation between the presence of TMJ clicking and a specific prior medical event (tonsillectomy). The data from computerized tracings of all subjects revealed no significant difference @ 0.05) in the mean angles of condylar guidance at any of the millimeter intervals examined regardless of whether the craniomandibular contact was an articulation of natural teeth or an articulation of maxillary natural teeth against a tray clutch. These results do not suggest that dynamic interarch tooth guidance or the change in vertical dimension reflect a significant alteration in the recordings of condylar guidance in clicking or nonclicking groups. (J PROSTHET DENT 1992;67:394-400.)

T he association

between

dental occlusion,

vertical

and condylar guidancehas long been debated, and reported conclusionsare mixed and often contradicto-

dimension,

Presented at the Academy of Denture Prosthetics meeting in Grand Bahamas. Tlinical Instructor, Department of Fixed Prosthodontics. bProfessor and Chairman, Department of Fixed Prosthodontics.

ry.l-18 Some of these studies reported that the temporomandibular joints (TMJs) and the guidance provided by the anterior teeth have a strong influence on the morphology of the teeth being restored.“-l* Dawson15stated that the combination of anterior guidance and condylar guidance determines the border path of each lower posterior tooth. Rugh and Johnson16stated that movementsof the

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Fig. 1. Measurements of condylar guidance anglesand characteristic tracing of condylar’s travel path in opening and closing clicks. 394

Fig.

2. Computerized axiograph. MARCH1992

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Fig. 3. Functional occlusal clutch.

Fig. 4. Measurements

of three reference points to the axis orbital plane.

mandible are determined by the shape, relative position, and anatomy of the teeth and joint. They described the relationship of jaw movements to occlusal and joint anatomy as a very important clinical factor. In fact, compelling data that explain the relationship between condylar inclination and tooth guidances and/or changes in vertical dimension are not presently available. The purpose of this study was to assess the influence of dynamic tooth guidance and the influence of change in vertical dimension on the recording of mandibular movements by tracing, measuring, and comparing the path of the hinge axis of the condyles in subjects with and without TMJ clicking through opening, protrusive, and lateral excursion movements.

State University of New York at Buffalo, and volunteer patients who were taught how to perform the jaw movements required by this investigation. Twenty-eight subjects 18 to 40 years of age participated in the study. Six men and seven women comprised the clicking group and nine men and six women without clicking served as controls. There were no significant differences in sex distribution and in age ranges between the two groups (range 18 to 40 years of age for the clicking group; 20 to 38 years of age for the nonclicking group). The occlusal classification of articulations for all subjects was Angle’s class I, and none of the subjects exhibited signs or symptoms of myofacial paindysfunction (MPD) or temporomandibular disorders (TMD).

MATERIAL

Equipment

AND

METHODS

Subjects for this study were obtained from student and dental assistant groups at the School of Dental Medicine, THE

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The Axiograph (Gamma Institute U.S.A., Rochester, N.Y.) instrument was developed by Dr. Rudolf Slavicek of 395

ALSAWAF

AND GARLAPO

Fig. 5. Tray clutch.

Table

I.

Protrusive

movements Left

Distance (mm) 1 2 3 4

Table

II.

Opening movements Left

side

Clutch

Mean angle

Standard deviation

A B A B A B A B

50.32 44.14 55.32 51.21 55.75 53.28 54.85 52.85

20.96 20.72 15.75 14.55 13.96 13.60 12.50 11.35

t Value

a-Tail prob.

1.77

0.087

1.56

0.131

1.17

0.252

1.24

0.227

Distance (mm) 1

2 3 4 5

A, Tray

clutch;

B, functional

occlusal

clutch.

6

Austria to depict three-dimensional condylar movement.lg, 2oThis instrument focuses on the bilateral location of posterior reference positions (transverse axis points) and the subsequent tracking and recording of movement of these points during opening-closing, protrusion-retrusion, and right/left excursions of the mandible. The orientation of these recordings is applied to the Cartesian coordinate system whereby the X-axis serves as a sagittal horizontal reference, the Y-axis serves as the transverse horizontal reference, and the Z-axis serves as the vertical axis. The current generation of this instrument, CADIAX, provides for computerized recordings of the movements and associated printing and calculations of the recording in relation to the coordinates. The computer calculates the X, Y, and 2 coordinates of mandibular movements along with the Bennett angle, horizontal condylar inclination from the orbital axis line for each millimeter distance of the hinge axis path (l-10 mm) of the condyle for both sides, starting from a reference point (Fig. 1). This computerized Axio-

396

7 8 9 10

A, Tray

separated

Clutch

Mean angle

A B A l3 A B A B A B A B A B A B A B A B

51.46 46.41 52.09 47.75 51.74 47.40 51.87 47.80 52.16 47.96 52.74 47.70 53.01 47.62 52.89 47.90 52.74 46.91 52.61 46.74

clutch;

B, functional

side

t

Standard deviation 20.02 19.71 19.75 19.48 19.49 19.02 19.32 19.07 18.40 18.52 16.71 16.54 15.14 14.96 11.71 10.68 9.41 9.16 9.17 9.14 occlussl

Value

a-Tail prob.

1.84

0.089

1.81

0.097

1.74

0.109

1.64

0.121

1.49

0.126

1.21

0.146

1.17

0.182

1.03

0.214

0.84

0.219

0.91

0.227

clutch.

graph instrument was used with cooperation of Gamma Institute for the purposesof this investigation (Fig. 2). The instrumentation afforded a rapid setup time for tracking and permitted the cranial recording flagsto be positioned in a stationary manner in apposition to the sidesof the face. The styli attached to the mandibular bow scribed paths of referencepoint travel, the shapeand direction of which was directly comparableto the movement of condyle itself.

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UL-U-

1-1-*-P

Fig. 6. Example of typical travel path of reference point in protrusive movement (noted for the first 4 mm) with functional occlusal clutch.

Fig. 7. Example of typical travel path of reference point in protrusive movement (noted for the first 4 mm) with tray clutch.

Procedure Each subject was comfortably seated in a dental chair and the experimenter’s index and middle fingers were placed over the left and right TMJ areas of the subject who was then asked to open, close, protrude, and make lateral excursive movements of the jaw several times. A definite single irregularity was classified as a click with this manual palpation method. Subjects filled out a medical history and dental questionnaire form. Maxillary and mandibular casts of each subject were obtained so that a cobalt chromium cast metal clutch could be fabricated for use during the recordings. These clutches were fabricated to extend around the labial arch of the mandibular teeth in a manner whereby they would be unobtrusive to the oral cavity and not affect the static contacting pattern of articulation or alter the patterns of tooth-guided movements (Fig. 3). The setup of recording apparatus for each subject consisted of luting the functional occlusal clutch to the mandibular teeth with a carboxylate cement (Duralon, Espe, Seefeld/Oberbay, Germany), affixing the cranial bow with its right and left recording plates over the respective condylar areas, and stabilizing it anteriorly by a glabellanasion seat and posteriorly by elastics transversing the parasagittal recording plates. The lower bow with its recording styli was attached to the functional occlusal clutch. At this juncture, measurements were made of the intercondylar distance (between the two recording flags), the distance right and left on the side arms of the maxillary bow to the anterior edge of the recording plate, and the distance the infraorbital pointer extended inferiorly to touch the orbital plane (Fig. 4). This information was entered in the computer to reference the axis orbital plane and provide parameters for computer-generated calculations. The first procedure with each subject was the delineation

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Fig. 8. Example of typical travel path of reference point in mediotrusion movement (noted for the first 5 mm) with functional occlusal clutch. of the posterior reference points at the rotational centers of each condyle. This was accomplished by operator-guided opening and closing of the mandible in the transverse horizontal axis and then adjusting the side arms of the lower bow until the styli did not arc but instead remained stationary. This process of adjustment was aided by observing the computer monitor, which graphically displayed the distance and direction of the required adjustment for the styli. Once the reference points were determined, their locations were entered in the computer. Subsequently, four separate mandibular movements were made-open-close, protrusion-retrusion, mediotrusion right, and mediotrusion left. Each of these movements was repeated and visualized on the monitor for reproducibility, and a final movement was then made and recorded in the computer. After the recording and storage of these move-

397

ALSAWAF

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GARLAPO

9. Example of typical travel path of reference point in mediotrusion movement (noted for the first 5 mm) with tray clutch. Fig.

mentsin the computer, the lower bow and functional clutch were removed. Next, a tray clutch wasseatedover the lower teeth and stabilized to the lower teeth with vinyl polysiloxane (hard body) (Ramitec, Espe, Germany) sothat when the mandible wasclosed,there wascontact betweenthe maxillary incisor teeth and the superior surface of the clutch (Fig. 5). The lower bow of the axiograph with its recording styli was then attached to the tray clutch, the styli were adjusted to reference positions, and the mandibular movements and recordingswere repeated as describedwith the functional occlusalclutch. RESULTS The initial analysiswasdirected at poolingthe data of all subjectsand comparing differences recorded between the functional occlusalclutch versusthe tray clutch. This was done by comparing angulationsof reference point travel in relation to the axis orbital plane for each millimeter of travel of the reference points. The results for the opening, protrusion, mediotrusion right, and mediotrusion left are reported in Tables I through III. Analysis of these results using a paired t-test revealed no significant difference for any of the various movements at any of the incremental distancesat the 95% level of confidence.Alternatively, the data were analyzed for individual subjectswith respect to specific descriptive inquiries. Twenty-five of the subjects exhibited protrusive and retrusive parasagittal travel paths that wererectilinear through 4 mm of referencepoint travel both when usingthe functional occlusalclutch and the tray clutch (Figs. 6 and 7). A movement of 4 mm waschosenbecausethis was the travel distance to edge-to-edgeincisal contact. Further, the comparisonof travel paths obtained with the functional occlusalclutch versus the tray clutch showedno statistical differences in angulation for 26 of the subjectsat the 95% level of confidence.

398

Fig. 10. Example of the travel path of referencepoint as noted in the compositetracing of all movements.

The travel paths of 23subjectsin right mediotrusion and 22 of the subjectsin left mediotrusion exhibited rectilinear travel paths through 5 mm of travel both when using the functional occlusalclutch and the tray clutch (Figs. 8 and 9). A movement of 5 mm was chosenbecausethis wasthe travel distanceto cusp-to-cuspcontact on the working side. A comparisonof travel paths using the functional occlusal clutch versus the tray clutch showedno statistical differencein angulation for 24 of the subjectsat the 95% level of confidence. Examination of the composite tracing of opening-closing, protrusion-retrusion, and mediotrusion right and left revealed the following: There wasno evidence of a Fischer angle in comparing the right and left mediotrusion paths and the protrusion-retrusion paths on the parasagittal tracings for 25 of the subjects(Fig. 10). The confluenceof the parasagittal open-close,protrusive-retrusive, and mediotrusive tracings wasvariable acrossthe 28 subjectsand for each subject. The pattern held true for both the tracingswith the functional occlusalclutch and the tray clutch (Fig. 11). Further, the confluenceof open-close,protrusiveretrusive, and mediotrusive tracings in horizontal plane weremorevariable than the parasagittal tracings acrossthe 28 subjectsand for each subject (Fig. 11). There wasdifficulty in avoiding positional drift of the transversereference points when there wasanterior craniomandibular contact either with occluding teeth or with teeth contacting the tray clutch (Fig. 12). Finally, Table IV displays the percentage of potential iatrogenic traumatic incidents as a sequillae of tonsillectomy in the clicking and nonclicking groups as obtained

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11. Composite tracing of all movements with tray separated clutch showsdeflection in the opening movement of subject with left clicking TMJ.

Fig.

Table

III.

Mediotrusive movements Left

Distance (mm)

1

Clutch

A

Mean angle

5

B A B

50.24 48.16 52.16 47.29 53.41 48.26 52.60 47.56 53.05 49.71

6

A

53.96

B

48.62

B 2

A

3

B A

4

B A

A, tray separated

clutch; B, functional

Table IV. Percentagesof tonsillectomy incidents in clicking and nonclicking groups

side Standard deviation

t Values

21.62 19.76 19.41 17.65 16.37 15.21 13.71 12.46 10.91 10.96 10.54 9.83

Group a-Tail prob.

1.83

0.079

1.78

0.082

1.61

0.096

1.56

0.093

1.37

0.131

1.39

0.148

occlusal clutch.

from the medical-dental history questionnaire forms. It showshigh chi-square statistics significant between two groups. DISCUSSION Analysis of the pooled data for all 28subjectsrevealedno differencesbetween the functional occlusalclutch and the tray clutch groups.This observation suggeststhat changes in referencepoint movement of the condyleswerenot gross. The useof the functional occlusalclutch, which identified

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Fig. 12. Example of positional drift of transverse reference points with functional occlusal clutch as compared with the tracing for the samepatient in Fig. 11.

Clicking Nonclicking

Yes

76.9 23.1

No

13.3 86.7

x2 = 11.49; df = 1; p > o.ooo7; * = 0.64.

a defined functional extent of tooth contact in protrusion aswell as lateral excursions,permitted notation of the accompanying extent of travel of the posterior reference points. This sameextent of travel could then be applied to tracings with the tray clutch in place. The lack of a statistical difference in protrusive-retrusive and lateral excursive tracingsfor 24 of the 28subjectsat the 95% level of confidencebetweenrecordingsmadewith the tray clutch and the functional occlusalclutch suggeststhat the change in vertical dimension produced by the tray clutch, along with the difference in vertical occlusionduring movements,did not producea statistically recognizable effect in reference point movement in the parasagittal plane. The inability to detect a Fischer angle (deviation between protrusive and mediotrusive paths of referencepoint travel) suggeststhat its reported existence is instrument derived. The lack of confluenceof compositetracings, especially of opening-closingand protrusion-retrusion tracings in the horizontal plane, strongly suggeststhat there is a physio-

399

ALSAWAF

logical range of movement of the condyles as they translate rather an absolute discrete path. The difficulty noted in maintaining transverse reference point positioning when there was either initial interarch tooth contact or tray-to-tooth contact suggests that either of these anterior craniomandibular contacts provide a positioning effect of the condyles. Finally, the previous history of iatrogenic incidents, such as tonsillectomy, could be relevant in subjects with temporomandibular joint clicking and supports the study done by Katzberg et a1.21in 1980, especially about the role of acute macrotrauma injuries as a cause in developing TMJ clicking in subjects who have a history of joint contusion, endoscopy, and tonsillectomy. SUMMARY

AND

CONCLUSION

Twenty-eight subjects were clinically examined and divided into two separate groups, those with and those without evidence of temporomandibular joint clicking. Information retrieved from a standardized questionnaire provided evidence of definite correlation between the presence of temporomandibular joint clicking and a specific prior medical event (tonsillectomy). The data gathered through computerized tracing of all subjects revealed no significant difference in the mean angles of condylar guidance (defined by reference point movement in the parasagittal plane) regardless of whether the craniomandibular contact was an articulation of natural teeth or an articulation of maxillary natural teeth against a tray clutch. Therefore, within the parameters of this investigation, there was no evidence to support the notion that either the change in vertical dimension or the influence of the dynamic interarch tooth guidance reflected a significant alteration in the recordings of condylar path travel. We express our appreciation to Mr. William Missert of the Gamma Institute, Rochester, N.Y., for his technical advice and programming assistance through the course of data collection.

AND

GARLAPO

2. Sigaroudi 3. 4. 5. 6. 7. 8. 9. 10.

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1980;43:331-337. 11. Shillingburg,

HT, Hobo S, Wbitsett LD. Fundamentals of fixed prosthodontics. 2nd ed. Chicago: Quintessence Publ, 1981;259-298. 12. Katz TG. The determinants of human occlusion. Los Angeles: Marina Press, 1972; vi. 13. Weinberg AL. Physiologic objective of reconstruction techniques. J PROSTHET DENT 1960;10:711-724. 14. Schuyler HC. The function and importance of incisal guidance in oral rehabilitation. J PROSTHET DENT 1963;13:1011-1030. 15. Dawson PE. Evaluation, diagnosis, and treatment of occlusal problems.

2nd ed. St. Louis: CV Mosby, 1989;chap 20, 237. RW. Mandibular movements. In: Mohl ND, Zarb GA, Carlsson GE, Rugh JD, eds. Textbook of occlusion. 1st ed., Chicago: Quintessence Publ, 1988;129-141. 17. Monson GS. Some important factors which influence occlusion. J Am Dent Assoc 1922;9:498-503. 18. Farrar WB. Disk derangement and dental occlusion. Changing concepts. Int J Periodont Restor Dent 1985;5:35-47. 19. Alsawaf M, Garlapo DA, Gale EN, Carter MJ. The relationship between condylar guidance and temporomandibular joint clicking. J PROSTHET 16. Rugh JD, Johnson

DENT 1989;61:349-354. 20. Slavicek R. Clinical

and instrumental functional analysis for diagnosis and treatment planning. Computer aided axiography. J Clin Orthod 1988;22:776-787. 21. Katzberg RW, Dolwick MF, Helms CA, Hopens T, Bales DJ, Goggs GC. Arthrotomography of the TMJ. Am J Roentgen01 1980;134:944. Reprint requests to: DR. MOUFID ALSAWAF P.O. Box 607151 ORLANDO. FL 32860-7151

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