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A technique for evaluation of centric relation tooth contacts. Part II: Following use of an occlusal splint for treatment of temporomandibular joint dysfunction
CRANIOMANDIBULAR SECTION
FUNCTION
AND DYSFUNCTION
EDITOR
GEORGE A. ZARB
A technique for evaluation of centric relation tooth contacts. Part II: Following use of an occlusal splint for treatment of temporomandibular joint dysfunction N. J. Capp, B.D.S., MS., F.D.S.R.C.S.(Ed),*
and J. A. Clayton,
D.D.S., M.S.**
Institute of Dental Surgery, London, England, and University of Michigan, School of Dentistry, Ann Arbor, Mich
lart I’ of this study described an indirect technique for meaSuring the point of initial tooth contact in centric relation. The technique was demonstrated using two different recording techniques in a subject without temporomandibular joint (TM J) dysfunction. This part of the study (1) describes the use of the technique to measure changes in the initial tooth contact during occlusal splint therapy in subjects with and without TMJ dysfunction, (2) compares the positions produced by each recording technique to determine whether bimanual manipulation achieved a stable position without use of a splint, and (3) analyzes pantographic tracings made at the beginning and end of the study for abnormal features that could be correlated with the clinical signs of dysfunction or occlusal interferences present at the end of splint therapy. Six sub,jects who presented with clinically diagnosed TM J dysfunction, were randomly selected. Two control subjects who had no history or clinical signs and symptoms of TMJ dysfunction and who were able to reproduce pantographic tracings were also selected. Copper-plated casts, anterior occlusal stops, and wax registration rims were fabricated for each subject in the manner described in Part I.’ The maxillary casts were mounted on the same semiad.justable articulator using an arbitrary axis face-bow transfer. After a detailed history and examination, the nature and location of the signs and symptoms of TMJ dysfunction were recorded. Four sets of pantographic tracings were made using the Denar pantograph (Denar Corp., Anaheim, Calif.). Each set included three right and three left lateral movements to verify superimposition of the lines. Clear, heat-cured acrylic resin maxillary occlusal splints were fabricated for each experimental subject at a minimal increase in occlusal vertical dimension. The splints were placed and adjusted to provide even contact
*Lecturer, Department of Conservative Dentistry, Institute of Dental surgery. **Professor, Department of Crown and Bridge, University of Michigan, School of Dentistry. THE JOURNAL
OE’ PROSTHETIC
DENTISTRY
Fig. 1. Maxillary
Fig. 2. Occlusal splint tacts and guidances.
occlusal splint.
showing
centric
relation
con-
for all mandibular supporting cusps and incisal edges in centric relation. A shallow, concave canine guidance was provided bilaterally. There were no other working or balancing contacts and an anterior disclusion in protrusive with no posterior contacts (Figs. 1 and 2). The splints were worn 24 hours per day but removed for eating. For 60 days each subject was seen at approximately weekly intervals to readjust the occlusal splint and 697
CAPP AND
---we_
= Eimanual
manipulation
= Anterior
jig
CLAYTON
70
60
.. i.(/ i\ * ’\_\
50
r
40
z
/I i
"E ;I
50
.’ 20
-
I .\ '\ \ \
\
10
I I I 0 *0 ciubjsct
-
1
2
4
3
5
6
7
8
LEFT X values,
1 Division
= 0.1
RIGHT -RIGHT
mm
Controls
Fig. 3. Changes in tooth contact position in mediolateral (X) direction. -
= Bimanual
manipulation
-m-w
= Anterior
jig
70
60
50
40 z z g
30
;" 20
10
0 Subject
-POSTERIOR
1
2
3
Y Values,
1 Division
5
4
= 0.1
6
7 8 Controls
mm
ANTERIOR
-
Fig. 4. Changes in tooth contact position in anteroposterior (Y) direction. maintain the occlusal requirements. At each visit six centric relation registrations were made, three by each of the two methods. These records were used to remount the mandibular casts and record the position of initial 698
tooth contact on the casts and numerically as described in Part I.’ Mean values for the X, Y, and Z coordinates were calculated, and graphs were plotted for each subject showing variations in the mean X, Y, and Z values over
NOVEMBER
1985
VOLUME
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NUMBER
5
CENTRIC
RELATION
TOOTH
CONTACTS
-
= Bimanual
manipulation
----
= Anterior
jig
I .i
Subject
1
2
3
4
5
6
7
8
Controls c
2 Values,
SUPERIOR
1 Division
= 0.1
mm INFERIOR
-.e
Fig. 5. Changes in tooth contact position in vertical (Z) direction. the experimental period. The total change in tooth contact position from the beginning to the end of the study was calculated for each subject and for the experimental and control groups collectively. At the end of the study new pantographic tracings were made and compared with the initial tracings. An attempt was made to correlate abnormal pantographic features with the location or movement of occlusal interferences noted during the study, or with the location of clinical signs and symptoms.
Table I. Total changes in tooth contact position obtained using bimanual manipulation (in millimeters) Subject No.
X
Y
X
1
+0.335* -1.004' -0.155' +0.390' +0.295' -0.015 -0.060 +0.060
+0.090* +1.560* -0.225' +0.280* +0.400* +0.500* -0.115 +0.080
+0.165' +0.215* +0.150* +0.130* +0.900* +0.260' +0.064 -0.110
2 3 4 5 6 7t 8t
RESULTS The changes that occurred in the mean tooth contact position in centric relation over the experimental period in X, Y, and Z directions were graphically described (Figs. 3 to 5). These graphs demonstrated that (1) a more consistent centric relation position was recorded in the control subjects than in the experimental group in all three planes; (2) in some of the experimental subjects the consistency of recordings improved with longer use of the splints; (3) bimanual manipulation did not produce a more consistent position than the anterior occlusal stop in either group; (4) in the control group, the anterior occlusal stop consistently produced a more posterior, superior tooth contact position than did bimanual manipulation; and (5) much larger variations in the posterior and superior tooth contact positions were found in the experimental groups. The total changes in tooth contact position from the
THE JOURNAL
OF PROSTHETIC
DENTISTRY
*Signilicanlwhen
compared
with
pilot
study
tComrols.
beginning to the end of the study were recorded in each direction for each subject (Tables I to III). Significant changes were also noted when compared with the standard deviations in the pilot study. Except for the vertical (Z) direction in subject No. 7, no significant change in the centric relation position occurred in the control subjects; but all experimental subjects showed significant change. The direction in which occlusal changes occurred relative to the reference edges of the slats from which the distances were measured was noted by a plus (+) or minus (-) sign. For X values, the dot may move to the right (+) or to the left (-). For Y values, the dot may
699
CAPP AND
CLAYTON
Fig. 6. A, Initial pantographic tracings for subject No. 2. PRI score is 40.75. See text for explanation of a, b, and c.
Table II. Total changes in tooth contact position obtained using an anterior stop (in millimeters)
occlusal
Subject No.
X
Y
Z
1 2 3 4 5 6 7t
+0.350* -0.730* +0.125’ +0.156’ +0.120* +0.050* +0.030 +0.030
+0.300* +1.320’ -0.340’ +0.155* +0.635’ +0.090 -0.003 +o.oso
+0.710* +1.000* -0.200” +0.270* -0.700* +0.360’ -0.120’ -0.040
*t
*Significant when compared with pilot study. tcontrols.
Fig. 6. B, Occlusal contacts for subject No. 2. Numbers 1 to 10 indicate sequence of clinical appointments. A = Bimanual manipulation; B = anterior occlusal stop. move anteriorly (+) or posteriorly (-). For Z values, the dot may move inferiorly (-t) or superiorly (-). Occlusal charts showing the changes in tooth contact position, signs and symptoms, and pantographic tracings were also analyzed. Several interesting trends were identified from these findings. Subject No. 2 presented with pain and muscle spasm in the right masseter and temporal muscles. With both recording techniques, the initial tooth contact in centric relation before splint therapy was located between the maxillary and mandibular left first and second molars. As the muscles relaxed and the mandible was repositioned during splint therapy, this contact moved and 700
stabilized on the right second molars when recorded using an anterior occlusal stop (Fig. 6, B). The initial signs and symptoms were also noted on the right side. Bimanual manipulation produced a more anterior tooth contact, which, although stable in position throughout the study, was not compatible with the changing pattern of contacts on the occlusal splint during the experimental period. The initial pantographic tracings showed a restricted condylar movement on the right (a), multiple centric contacts (b), and a pronounced avoidance pattern in lateral movement (c). The pantographic reproducibility index (PRI) score was 40.75, which indicates a moderate level of dysfunction (Fig. 6, A). The PRI was 17.25 at the conclusion of the study after 60 days of splint therapy (Fig. 7). The final tracings showed NOVEMBER
1985
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TOOTH
COhlTACTS
Fig. 7. Final pantographic
Table III. Means and standard deviations
for changes in tooth contact position
Experimental group
0.320 0.300
k +
0.242 0.357
0.470 0.515
+ k
Z 0.440 0.545
increased reproducibility, but restricted right-side condylar movement remained, because a longer period of splint therapy was needed for complete alleviation of signs and symptoms. Subject No. 4 presented with pain and tenderness in the region of the left TMJ. The initial tracings showed absence of the Fisher angle with crossover of the protrusive and orbiting paths on the left vertical recording table (Fig. 8, A, a). Before splint therapy, this initially recordeld occlusal contact was located between the right second molars in both recording techniques. After approximately 2 weeks of splint therapy, the initial occlusal contact, as recorded with an anterior occlusal stop, had stabilized on a gold crown placed 1 year previously on the mandibular left first molar. The initial occlusal contact produced by bimanual manipulation occurred more anteriorly (Fig. 8, B). The initial tooth contact recorded with an anterior occlusal stop on subject No. 6 changed from the left first premolars to the left second molars after 2 weeks of splint therapy (Fig. 9, B). The contact recorded using bimanual manipulation remained on the first premolars, which was not consistent with the changing pattern of THE JOURNAL
OF PROSTHETIC
DENTISTRY
for both groups Control group
Y
X Bimanual manipulation Anterior occlusal stop.
tracings for subject No. 2. PRI score is 17.25.
0.435 0.325
It +
X 0.403 0.251
0.060 0.030
Y lr 0 -+ 0
0.095 0.040
-+ 0.024 + 0.054
Z 0.085 0.080
+ +
0.032 0.056
occlusal contacts observed on the occlusal splint during the study. This subject had pain, tenderness, and hypertrophy of the left masseter muscle approximately 2 years after completion of orthodontic treatment. She had no anterior guidance in her postorthodontic occlusion. The initial pantographic tracings showed an absence of the Fisher angle on the left (a), and nonreproducibility of the orbiting (6) and working (c) condylar paths on the left (Fig. 9, A). Fig. 10 shows the occlusal chart and tracings from control subject No. 8. The pantographic tracings for subject No. 8 were reproducible and had no abnormal features (Fig. 10, A). The occlusal chart indicated a consistent mandibular position recorded by both methods of centric relation registration (Fig. 10, B). As in part I of this study’ and in many experimental subjects, bimanual manipulation produced a more anterior tooth contact, which would indicate a more anterior, inferior condylar position.
DISCUSSION The time limit imposed on this study precluded a large sample or a sufficient duration
of splint therapy
to 701
CAPP AND
CLAYTON
Fig. 8. A, Initial pantographic tracings for subject No. 4. See text for explanation of u.
Fig. 8. B, Occlusal contacts for subject No. 4. achieve reproducible mandibular border positions in all experimental subjects. Some of the results, therefore, should be interpreted as trends rather than conclusions. The more consistent centric relation positions recorded in subjects free of TMJ dysfunction concur with findings of previous studies.2t3 It is important to eliminate dysfunction and achieve a stable maxillomandibular relation before occlusal adjustment or restoration. Although use of an occlusal splint can result in a stable occlusal position, some experimental subjects with a history of long-standing dysfunction would require a
702
longer period of splint therapy than was provided in this study.‘s5 It is difficult to determine clinically when all dysfunction has been eliminated and required occlusal restoration can proceed. In this study, clinical signs and symptoms were alleviated before a stable jaw relation or a reproducible pantographic tracing could be recorded. This finding indicates the need to remount casts and verify changes in initial tooth contacts or remake pantographic tracings to determine the end point for splint therapy.6 It was found that bimanual manipulation could not locate a stable jaw relation in the experimental group. In several of the experimental subjects, the occlusal charts indicated an apparently more consistent initial tooth contact by recording with bimanual manipulation. This finding, however, is not indicative of a more consistent centric relation position, because significant changes -in initial tooth contacts while using occlusal splints indicate mandibular repositioning. When the occlusal splints and the anterior occlusal stop were removed, however, the return of occlusal deflections retriggered the muscle spasm through proprioceptive feedback. It was then more difficult to make an accurate recording of the changes in centric relation position achieved by occlusal splint therapy. The use of an anterior occlusal stop separated the posterior teeth and facilitated recording procedures. The initial tooth contact positions recorded by the two
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1985
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CONTACTS
Fig. 9. A, Initial pantographic explanation of a, b, and c.
tracings for subject No. 6. PRI score is 16.5. See text for
methods in the control subjects agreed with those achieved in part I.’ This finding was not consistent in the experimental group because of the overriding effect of hypertonic muscles on the recording procedures. Some of the experimental subjects only presented for occlusal splint adjustment every 2 weeks, and they showed less improvement than those who presented weekly. These subjects related that their occlusion was comfortable aga.inst the occlusal splint for 5 or 6 days only. Their occlusions then appeared to change and their symptoms gradually returned until the occlusion was readjusted. This indicates the need to adjust occlusal splints frequently enough to accommodate occlusal changes that result from muscle relaxation and mandibular repositioning. Analysis of the findings revealed that occlusal splints relaxed the subjects’ muscles and permitted location of occlusal interferences that had previously been hidden by the neuromuscular system. F:or example, subject No. 4 had experienced onset of symptoms 1 year previously, soon after the placement of a complete crown on the mandibular left first molar. The initial occlusal contact appeared to be on the right. It was only after several weeks of occlusal splint therapy that it stabilized on this crown. The recording styli provide a more accurate means of monitoring this position than observation of contacts on casts. In five of the six experimental subjects, the final
jaw registration
THE JOURNAL
OF PROSTHETIC
DENTlSTRY
Fig. 9. B, Occlusal contacts for subject No. 6.
occlusal interferences were located on the same side as clinical signs and symptoms and abnormal features were located in the initial pantographic tracings. The major abnormal features on the symptomatic side were (1) unstable centric contacts, (2) lack of a Fisher angle, and (3) restricted condylar movements. The anterior pantographic tracing tables showed avoidance patterns in lateral movement that were associated with the location of the occlusal interference and their obstruction to border movements of the mandible. By analyzing the changes in X, Y, and Z values recorded on the articulator and the pattern of changing
703
CAPP AND
CLAYTON
Fig. 10. A, Pantographic tracings for subject No. 8. PRI score is 6.
a posterior, superior repositioning of the symptomatic condyles. These findings are in contrast to those of Kovaleski and DeBoever,B who measured mandibular repositioning directly on an occlusal splint and concluded that occlusal contacts usually moved anteriorly and toward the affected side. Subject selection often influences the outcome of studies of short duration and small sample size. Another investigation with a larger sample size should be undertaken and an attempt made to correlate the direction of condylar displacement with the subjects’ occlusal relationships. SUMMARY
Fig. 10. B, Occlusal contacts for subject No. 8. occlusal contacts on the casts, the direction of mandibular repositioning could be postulated. In subject No. 2 the data revealed movement downward, forward, and to the left as noted on the right symptomatic side. This subject had a severe vertical overlap of the incisors and a collapsed posterior occlusion. It appears that the right condyle had been posteriorly displaced and the splint permitted forward movement. Subject Nos. 2, 5, and 6 had Angle Class I occlusions, but initial occlusal contacts as recorded on the occlusal charts moved distally on the symptomatic side as splint therapy progressed. An anterior occlusal stop was used to record the changing occlusal contacts, which indicated
704
AND CONCLUSIONS
The purpose of this study was to determine the effect of TM J dysfunction on the recording of centric relation. Centric relation was recorded using an anterior occlusal stop and by bimanual manipulation. Changes in occlusal contacts were recorded before and after occlusal splint therapy in six subjects with TMJ dysfunction. The pantographic reproducibility index and clinical signs and symptoms were used to determine the presence or absence of dysfunction. Use of the anterior occlusal stop resulted in a more posterior, superior initial tooth contact position when compared with bimanual manipulation. Occlusal contact positions were less consistent in TMJ dysfunction subjects than in control subjects. Initial occlusal contacts changed toward centric relation as the dysfunction disappeared. Final occlusal contact was found on the side NOVEMBER
1985
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TOOTH
CONTACTS
where clinical signs and symptoms occurred. The condyle on the affected side appeared to be repositioned posteriorly and superiorly in most instances. Occlusal splint therapy was more effective when the splint was adjusted weekly. This study indicates the need to eliminate TMJ dysfunction before recording centric relation or adjusting the occlusion. Occlusal interferences found with TMJ dysfunction are not the same: as occlusal interferences found when Tn4J dysfunction is absent. Abnormal features on pantographic tracings may aid in indicating the presence of occlusal interferences. Occlusal adjustment in the presence of TMJ dysfunction would result in erroneous occlusal reduction. REFERENCES Capp NJ, Clayton JA: A technique for evaluation of centric relation tooth contacts. Part I: During normal temporomandibulx joim furwion. J PROSTHET DENT 543569, 1985. 2. Dyer EH: Importance of a stable maxillomandibular relation. J PROSTH~~.DE.NT 30~241, 1973. 1.
Myofascial pain-dysfunction: signs and symptoms
3.
4.
5.
6.
7. 8.
Shields JM, Clayton JA, Sindledecker LD: Using pantographic tracings to detect temporomandibular joint and muscle dysfunction. J PROSTHETDENT 39:80, 1978. Roura N, Clayton JA: Pantographic records on temporomandibular joint dysfunction subjects treated with occlusal splints: A progress report. J PROSTHET DENT 33:442, 1975. Beard CC, Clayton JA: Effects of occlusal splint therapy on temporomandibular joint dysfunction. J PROSTHET L)ENT 33:324, 1980. Crispin BJ, Myers GE, Clayton JA: Effects of occlusal therapy on pantographic reproducibility of mandibular border movements. J PROSTHET DENT 40~29, 1978. Dawson PE: Evaluation, Diagnosis and Treatment of Occlusal Problems. St. Louis, 1974, The CV Mosby Co, p 75. Koveleski WC, DeBoever J: Influence of occlusal splints on jaw position and musculature in patients with temporomandibular joint dysfunction. J PROSTHET DENT 33:321 1 1975.
/:~;llri,,l nY/rlr’,l\ Ill.’ DR. N. J. CAPP EASTMAN DENTAL HOSPITAL C;RAY’S INN ROAD
I,ONDON, \V(:lX
8LD
ENGLAN~I
Subjective
Theo H. Hijzen, Ph.D.,* and Jef L. Slangen, Ph.D.** State University of Utrecht, Utrccht, The Netherlands
P
atients with pain and mandibular dysfunction constitute a heterogeneous population with a proposed multifactorial etiology. 1,2 Rugh and Solberg’ discussed the definitional problems associated with this disorder and suggested temporomandibular pain and dysfunction (TMD) as the most general label for the disorder. There is some agreement that TMD should be defined by pain and tenderness in the region of the muscles of mastication, sounds during condylar movement, and limitations of mandibular movement. If these three symptoms are present and there is no radiographic evidence of joint abnormalities or joint tenderness during palpation of the external meatus, the label myofascial pain-dysfunction (MPD) is applied’a3 although a sharp distinction between TMD and MPD is frequently not possible. Furthermore, it is not known to what extent signs and
*Associate, Department of Psychophysiology. **Professor and Head, Department of Psychophysiology. THE JOURNAL
OF PROSTHETIC
DENTISTRY
symptoms are specific for MPD patients mainly because of procedural and methodologic problems. In the absence of standardized measurement techniques, results from separate sources cannot be easily compared. In addition reliable control group data are the exception, not the rule. In most studies, a single group approach is used. Information is obtained from MPD patients,4*‘6 from a heterogeneous patient population,” or from a nonpatient population.‘8-20 These single group designs give no information about the specific characteristics of MPD patients. A few studies2’-23compared data obtained from MPD patients with data obtained from an adequate control group; that is, non-MPD patients. These studies were, however, not directed at subjective signs and symptoms. Moreover, apart from the study by HeloE et a1.,2’the experimental and control groups were not matched for age and sex. In the present study, many of the subjective symptoms and patient characteristics mentioned in the literature were brought together in a questionnaire. The main 705
FUNCTION
AND DYSFUNCTION
EDITOR
GEORGE A. ZARB
A technique for evaluation of centric relation tooth contacts. Part II: Following use of an occlusal splint for treatment of temporomandibular joint dysfunction N. J. Capp, B.D.S., MS., F.D.S.R.C.S.(Ed),*
and J. A. Clayton,
D.D.S., M.S.**
Institute of Dental Surgery, London, England, and University of Michigan, School of Dentistry, Ann Arbor, Mich
lart I’ of this study described an indirect technique for meaSuring the point of initial tooth contact in centric relation. The technique was demonstrated using two different recording techniques in a subject without temporomandibular joint (TM J) dysfunction. This part of the study (1) describes the use of the technique to measure changes in the initial tooth contact during occlusal splint therapy in subjects with and without TMJ dysfunction, (2) compares the positions produced by each recording technique to determine whether bimanual manipulation achieved a stable position without use of a splint, and (3) analyzes pantographic tracings made at the beginning and end of the study for abnormal features that could be correlated with the clinical signs of dysfunction or occlusal interferences present at the end of splint therapy. Six sub,jects who presented with clinically diagnosed TM J dysfunction, were randomly selected. Two control subjects who had no history or clinical signs and symptoms of TMJ dysfunction and who were able to reproduce pantographic tracings were also selected. Copper-plated casts, anterior occlusal stops, and wax registration rims were fabricated for each subject in the manner described in Part I.’ The maxillary casts were mounted on the same semiad.justable articulator using an arbitrary axis face-bow transfer. After a detailed history and examination, the nature and location of the signs and symptoms of TMJ dysfunction were recorded. Four sets of pantographic tracings were made using the Denar pantograph (Denar Corp., Anaheim, Calif.). Each set included three right and three left lateral movements to verify superimposition of the lines. Clear, heat-cured acrylic resin maxillary occlusal splints were fabricated for each experimental subject at a minimal increase in occlusal vertical dimension. The splints were placed and adjusted to provide even contact
*Lecturer, Department of Conservative Dentistry, Institute of Dental surgery. **Professor, Department of Crown and Bridge, University of Michigan, School of Dentistry. THE JOURNAL
OE’ PROSTHETIC
DENTISTRY
Fig. 1. Maxillary
Fig. 2. Occlusal splint tacts and guidances.
occlusal splint.
showing
centric
relation
con-
for all mandibular supporting cusps and incisal edges in centric relation. A shallow, concave canine guidance was provided bilaterally. There were no other working or balancing contacts and an anterior disclusion in protrusive with no posterior contacts (Figs. 1 and 2). The splints were worn 24 hours per day but removed for eating. For 60 days each subject was seen at approximately weekly intervals to readjust the occlusal splint and 697
CAPP AND
---we_
= Eimanual
manipulation
= Anterior
jig
CLAYTON
70
60
.. i.(/ i\ * ’\_\
50
r
40
z
/I i
"E ;I
50
.’ 20
-
I .\ '\ \ \
\
10
I I I 0 *0 ciubjsct
-
1
2
4
3
5
6
7
8
LEFT X values,
1 Division
= 0.1
RIGHT -RIGHT
mm
Controls
Fig. 3. Changes in tooth contact position in mediolateral (X) direction. -
= Bimanual
manipulation
-m-w
= Anterior
jig
70
60
50
40 z z g
30
;" 20
10
0 Subject
-POSTERIOR
1
2
3
Y Values,
1 Division
5
4
= 0.1
6
7 8 Controls
mm
ANTERIOR
-
Fig. 4. Changes in tooth contact position in anteroposterior (Y) direction. maintain the occlusal requirements. At each visit six centric relation registrations were made, three by each of the two methods. These records were used to remount the mandibular casts and record the position of initial 698
tooth contact on the casts and numerically as described in Part I.’ Mean values for the X, Y, and Z coordinates were calculated, and graphs were plotted for each subject showing variations in the mean X, Y, and Z values over
NOVEMBER
1985
VOLUME
54
NUMBER
5
CENTRIC
RELATION
TOOTH
CONTACTS
-
= Bimanual
manipulation
----
= Anterior
jig
I .i
Subject
1
2
3
4
5
6
7
8
Controls c
2 Values,
SUPERIOR
1 Division
= 0.1
mm INFERIOR
-.e
Fig. 5. Changes in tooth contact position in vertical (Z) direction. the experimental period. The total change in tooth contact position from the beginning to the end of the study was calculated for each subject and for the experimental and control groups collectively. At the end of the study new pantographic tracings were made and compared with the initial tracings. An attempt was made to correlate abnormal pantographic features with the location or movement of occlusal interferences noted during the study, or with the location of clinical signs and symptoms.
Table I. Total changes in tooth contact position obtained using bimanual manipulation (in millimeters) Subject No.
X
Y
X
1
+0.335* -1.004' -0.155' +0.390' +0.295' -0.015 -0.060 +0.060
+0.090* +1.560* -0.225' +0.280* +0.400* +0.500* -0.115 +0.080
+0.165' +0.215* +0.150* +0.130* +0.900* +0.260' +0.064 -0.110
2 3 4 5 6 7t 8t
RESULTS The changes that occurred in the mean tooth contact position in centric relation over the experimental period in X, Y, and Z directions were graphically described (Figs. 3 to 5). These graphs demonstrated that (1) a more consistent centric relation position was recorded in the control subjects than in the experimental group in all three planes; (2) in some of the experimental subjects the consistency of recordings improved with longer use of the splints; (3) bimanual manipulation did not produce a more consistent position than the anterior occlusal stop in either group; (4) in the control group, the anterior occlusal stop consistently produced a more posterior, superior tooth contact position than did bimanual manipulation; and (5) much larger variations in the posterior and superior tooth contact positions were found in the experimental groups. The total changes in tooth contact position from the
THE JOURNAL
OF PROSTHETIC
DENTISTRY
*Signilicanlwhen
compared
with
pilot
study
tComrols.
beginning to the end of the study were recorded in each direction for each subject (Tables I to III). Significant changes were also noted when compared with the standard deviations in the pilot study. Except for the vertical (Z) direction in subject No. 7, no significant change in the centric relation position occurred in the control subjects; but all experimental subjects showed significant change. The direction in which occlusal changes occurred relative to the reference edges of the slats from which the distances were measured was noted by a plus (+) or minus (-) sign. For X values, the dot may move to the right (+) or to the left (-). For Y values, the dot may
699
CAPP AND
CLAYTON
Fig. 6. A, Initial pantographic tracings for subject No. 2. PRI score is 40.75. See text for explanation of a, b, and c.
Table II. Total changes in tooth contact position obtained using an anterior stop (in millimeters)
occlusal
Subject No.
X
Y
Z
1 2 3 4 5 6 7t
+0.350* -0.730* +0.125’ +0.156’ +0.120* +0.050* +0.030 +0.030
+0.300* +1.320’ -0.340’ +0.155* +0.635’ +0.090 -0.003 +o.oso
+0.710* +1.000* -0.200” +0.270* -0.700* +0.360’ -0.120’ -0.040
*t
*Significant when compared with pilot study. tcontrols.
Fig. 6. B, Occlusal contacts for subject No. 2. Numbers 1 to 10 indicate sequence of clinical appointments. A = Bimanual manipulation; B = anterior occlusal stop. move anteriorly (+) or posteriorly (-). For Z values, the dot may move inferiorly (-t) or superiorly (-). Occlusal charts showing the changes in tooth contact position, signs and symptoms, and pantographic tracings were also analyzed. Several interesting trends were identified from these findings. Subject No. 2 presented with pain and muscle spasm in the right masseter and temporal muscles. With both recording techniques, the initial tooth contact in centric relation before splint therapy was located between the maxillary and mandibular left first and second molars. As the muscles relaxed and the mandible was repositioned during splint therapy, this contact moved and 700
stabilized on the right second molars when recorded using an anterior occlusal stop (Fig. 6, B). The initial signs and symptoms were also noted on the right side. Bimanual manipulation produced a more anterior tooth contact, which, although stable in position throughout the study, was not compatible with the changing pattern of contacts on the occlusal splint during the experimental period. The initial pantographic tracings showed a restricted condylar movement on the right (a), multiple centric contacts (b), and a pronounced avoidance pattern in lateral movement (c). The pantographic reproducibility index (PRI) score was 40.75, which indicates a moderate level of dysfunction (Fig. 6, A). The PRI was 17.25 at the conclusion of the study after 60 days of splint therapy (Fig. 7). The final tracings showed NOVEMBER
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Fig. 7. Final pantographic
Table III. Means and standard deviations
for changes in tooth contact position
Experimental group
0.320 0.300
k +
0.242 0.357
0.470 0.515
+ k
Z 0.440 0.545
increased reproducibility, but restricted right-side condylar movement remained, because a longer period of splint therapy was needed for complete alleviation of signs and symptoms. Subject No. 4 presented with pain and tenderness in the region of the left TMJ. The initial tracings showed absence of the Fisher angle with crossover of the protrusive and orbiting paths on the left vertical recording table (Fig. 8, A, a). Before splint therapy, this initially recordeld occlusal contact was located between the right second molars in both recording techniques. After approximately 2 weeks of splint therapy, the initial occlusal contact, as recorded with an anterior occlusal stop, had stabilized on a gold crown placed 1 year previously on the mandibular left first molar. The initial occlusal contact produced by bimanual manipulation occurred more anteriorly (Fig. 8, B). The initial tooth contact recorded with an anterior occlusal stop on subject No. 6 changed from the left first premolars to the left second molars after 2 weeks of splint therapy (Fig. 9, B). The contact recorded using bimanual manipulation remained on the first premolars, which was not consistent with the changing pattern of THE JOURNAL
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for both groups Control group
Y
X Bimanual manipulation Anterior occlusal stop.
tracings for subject No. 2. PRI score is 17.25.
0.435 0.325
It +
X 0.403 0.251
0.060 0.030
Y lr 0 -+ 0
0.095 0.040
-+ 0.024 + 0.054
Z 0.085 0.080
+ +
0.032 0.056
occlusal contacts observed on the occlusal splint during the study. This subject had pain, tenderness, and hypertrophy of the left masseter muscle approximately 2 years after completion of orthodontic treatment. She had no anterior guidance in her postorthodontic occlusion. The initial pantographic tracings showed an absence of the Fisher angle on the left (a), and nonreproducibility of the orbiting (6) and working (c) condylar paths on the left (Fig. 9, A). Fig. 10 shows the occlusal chart and tracings from control subject No. 8. The pantographic tracings for subject No. 8 were reproducible and had no abnormal features (Fig. 10, A). The occlusal chart indicated a consistent mandibular position recorded by both methods of centric relation registration (Fig. 10, B). As in part I of this study’ and in many experimental subjects, bimanual manipulation produced a more anterior tooth contact, which would indicate a more anterior, inferior condylar position.
DISCUSSION The time limit imposed on this study precluded a large sample or a sufficient duration
of splint therapy
to 701
CAPP AND
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Fig. 8. A, Initial pantographic tracings for subject No. 4. See text for explanation of u.
Fig. 8. B, Occlusal contacts for subject No. 4. achieve reproducible mandibular border positions in all experimental subjects. Some of the results, therefore, should be interpreted as trends rather than conclusions. The more consistent centric relation positions recorded in subjects free of TMJ dysfunction concur with findings of previous studies.2t3 It is important to eliminate dysfunction and achieve a stable maxillomandibular relation before occlusal adjustment or restoration. Although use of an occlusal splint can result in a stable occlusal position, some experimental subjects with a history of long-standing dysfunction would require a
702
longer period of splint therapy than was provided in this study.‘s5 It is difficult to determine clinically when all dysfunction has been eliminated and required occlusal restoration can proceed. In this study, clinical signs and symptoms were alleviated before a stable jaw relation or a reproducible pantographic tracing could be recorded. This finding indicates the need to remount casts and verify changes in initial tooth contacts or remake pantographic tracings to determine the end point for splint therapy.6 It was found that bimanual manipulation could not locate a stable jaw relation in the experimental group. In several of the experimental subjects, the occlusal charts indicated an apparently more consistent initial tooth contact by recording with bimanual manipulation. This finding, however, is not indicative of a more consistent centric relation position, because significant changes -in initial tooth contacts while using occlusal splints indicate mandibular repositioning. When the occlusal splints and the anterior occlusal stop were removed, however, the return of occlusal deflections retriggered the muscle spasm through proprioceptive feedback. It was then more difficult to make an accurate recording of the changes in centric relation position achieved by occlusal splint therapy. The use of an anterior occlusal stop separated the posterior teeth and facilitated recording procedures. The initial tooth contact positions recorded by the two
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Fig. 9. A, Initial pantographic explanation of a, b, and c.
tracings for subject No. 6. PRI score is 16.5. See text for
methods in the control subjects agreed with those achieved in part I.’ This finding was not consistent in the experimental group because of the overriding effect of hypertonic muscles on the recording procedures. Some of the experimental subjects only presented for occlusal splint adjustment every 2 weeks, and they showed less improvement than those who presented weekly. These subjects related that their occlusion was comfortable aga.inst the occlusal splint for 5 or 6 days only. Their occlusions then appeared to change and their symptoms gradually returned until the occlusion was readjusted. This indicates the need to adjust occlusal splints frequently enough to accommodate occlusal changes that result from muscle relaxation and mandibular repositioning. Analysis of the findings revealed that occlusal splints relaxed the subjects’ muscles and permitted location of occlusal interferences that had previously been hidden by the neuromuscular system. F:or example, subject No. 4 had experienced onset of symptoms 1 year previously, soon after the placement of a complete crown on the mandibular left first molar. The initial occlusal contact appeared to be on the right. It was only after several weeks of occlusal splint therapy that it stabilized on this crown. The recording styli provide a more accurate means of monitoring this position than observation of contacts on casts. In five of the six experimental subjects, the final
jaw registration
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Fig. 9. B, Occlusal contacts for subject No. 6.
occlusal interferences were located on the same side as clinical signs and symptoms and abnormal features were located in the initial pantographic tracings. The major abnormal features on the symptomatic side were (1) unstable centric contacts, (2) lack of a Fisher angle, and (3) restricted condylar movements. The anterior pantographic tracing tables showed avoidance patterns in lateral movement that were associated with the location of the occlusal interference and their obstruction to border movements of the mandible. By analyzing the changes in X, Y, and Z values recorded on the articulator and the pattern of changing
703
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Fig. 10. A, Pantographic tracings for subject No. 8. PRI score is 6.
a posterior, superior repositioning of the symptomatic condyles. These findings are in contrast to those of Kovaleski and DeBoever,B who measured mandibular repositioning directly on an occlusal splint and concluded that occlusal contacts usually moved anteriorly and toward the affected side. Subject selection often influences the outcome of studies of short duration and small sample size. Another investigation with a larger sample size should be undertaken and an attempt made to correlate the direction of condylar displacement with the subjects’ occlusal relationships. SUMMARY
Fig. 10. B, Occlusal contacts for subject No. 8. occlusal contacts on the casts, the direction of mandibular repositioning could be postulated. In subject No. 2 the data revealed movement downward, forward, and to the left as noted on the right symptomatic side. This subject had a severe vertical overlap of the incisors and a collapsed posterior occlusion. It appears that the right condyle had been posteriorly displaced and the splint permitted forward movement. Subject Nos. 2, 5, and 6 had Angle Class I occlusions, but initial occlusal contacts as recorded on the occlusal charts moved distally on the symptomatic side as splint therapy progressed. An anterior occlusal stop was used to record the changing occlusal contacts, which indicated
704
AND CONCLUSIONS
The purpose of this study was to determine the effect of TM J dysfunction on the recording of centric relation. Centric relation was recorded using an anterior occlusal stop and by bimanual manipulation. Changes in occlusal contacts were recorded before and after occlusal splint therapy in six subjects with TMJ dysfunction. The pantographic reproducibility index and clinical signs and symptoms were used to determine the presence or absence of dysfunction. Use of the anterior occlusal stop resulted in a more posterior, superior initial tooth contact position when compared with bimanual manipulation. Occlusal contact positions were less consistent in TMJ dysfunction subjects than in control subjects. Initial occlusal contacts changed toward centric relation as the dysfunction disappeared. Final occlusal contact was found on the side NOVEMBER
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where clinical signs and symptoms occurred. The condyle on the affected side appeared to be repositioned posteriorly and superiorly in most instances. Occlusal splint therapy was more effective when the splint was adjusted weekly. This study indicates the need to eliminate TMJ dysfunction before recording centric relation or adjusting the occlusion. Occlusal interferences found with TMJ dysfunction are not the same: as occlusal interferences found when Tn4J dysfunction is absent. Abnormal features on pantographic tracings may aid in indicating the presence of occlusal interferences. Occlusal adjustment in the presence of TMJ dysfunction would result in erroneous occlusal reduction. REFERENCES Capp NJ, Clayton JA: A technique for evaluation of centric relation tooth contacts. Part I: During normal temporomandibulx joim furwion. J PROSTHET DENT 543569, 1985. 2. Dyer EH: Importance of a stable maxillomandibular relation. J PROSTH~~.DE.NT 30~241, 1973. 1.
Myofascial pain-dysfunction: signs and symptoms
3.
4.
5.
6.
7. 8.
Shields JM, Clayton JA, Sindledecker LD: Using pantographic tracings to detect temporomandibular joint and muscle dysfunction. J PROSTHETDENT 39:80, 1978. Roura N, Clayton JA: Pantographic records on temporomandibular joint dysfunction subjects treated with occlusal splints: A progress report. J PROSTHET DENT 33:442, 1975. Beard CC, Clayton JA: Effects of occlusal splint therapy on temporomandibular joint dysfunction. J PROSTHET L)ENT 33:324, 1980. Crispin BJ, Myers GE, Clayton JA: Effects of occlusal therapy on pantographic reproducibility of mandibular border movements. J PROSTHET DENT 40~29, 1978. Dawson PE: Evaluation, Diagnosis and Treatment of Occlusal Problems. St. Louis, 1974, The CV Mosby Co, p 75. Koveleski WC, DeBoever J: Influence of occlusal splints on jaw position and musculature in patients with temporomandibular joint dysfunction. J PROSTHET DENT 33:321 1 1975.
/:~;llri,,l nY/rlr’,l\ Ill.’ DR. N. J. CAPP EASTMAN DENTAL HOSPITAL C;RAY’S INN ROAD
I,ONDON, \V(:lX
8LD
ENGLAN~I
Subjective
Theo H. Hijzen, Ph.D.,* and Jef L. Slangen, Ph.D.** State University of Utrecht, Utrccht, The Netherlands
P
atients with pain and mandibular dysfunction constitute a heterogeneous population with a proposed multifactorial etiology. 1,2 Rugh and Solberg’ discussed the definitional problems associated with this disorder and suggested temporomandibular pain and dysfunction (TMD) as the most general label for the disorder. There is some agreement that TMD should be defined by pain and tenderness in the region of the muscles of mastication, sounds during condylar movement, and limitations of mandibular movement. If these three symptoms are present and there is no radiographic evidence of joint abnormalities or joint tenderness during palpation of the external meatus, the label myofascial pain-dysfunction (MPD) is applied’a3 although a sharp distinction between TMD and MPD is frequently not possible. Furthermore, it is not known to what extent signs and
*Associate, Department of Psychophysiology. **Professor and Head, Department of Psychophysiology. THE JOURNAL
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symptoms are specific for MPD patients mainly because of procedural and methodologic problems. In the absence of standardized measurement techniques, results from separate sources cannot be easily compared. In addition reliable control group data are the exception, not the rule. In most studies, a single group approach is used. Information is obtained from MPD patients,4*‘6 from a heterogeneous patient population,” or from a nonpatient population.‘8-20 These single group designs give no information about the specific characteristics of MPD patients. A few studies2’-23compared data obtained from MPD patients with data obtained from an adequate control group; that is, non-MPD patients. These studies were, however, not directed at subjective signs and symptoms. Moreover, apart from the study by HeloE et a1.,2’the experimental and control groups were not matched for age and sex. In the present study, many of the subjective symptoms and patient characteristics mentioned in the literature were brought together in a questionnaire. The main 705