Download 12 .the Temporomandibular Opening Index and Condylar Asymmetry in Myogenous TMD and Non- TMD Patients Report of...
Q U I N T E S S E N C E I N T E R N AT I O N A L
PROSTHODONTICS/OROFACIAL PAIN The temporomandibular opening index and condylar asymmetry in myogenous TMD and nonTMD patients: Report of a pilot study Vesna V. Karic, DDS, MSc1/Victor J. Miller, BChD2/Swati R. Nehete, BDS, MSc, MFDS2/Ronen Ofec, DMD, MSc3/Ami Smidt, DMD, MSc4 Objective: The temporomandibular opening index (TOI) is endfeel distance divided by active and passive mouth opening. The asymmetry index (AI) is a measure of difference in left and right condylar heights. This study examined the relationship between AI and TOI in myogenous TMD and non-TMD patients. Method and Materials: Fourteen myogenous 5.%QBUJFOUTEJBHOPTFECZUIF3FTFBSDI%JBHOPTUJD$SJUFSJBGPS5FNQPSPNBOEJCVMBS %JTPSEFST 3%$5.% XFSFSFDSVJUFE NBOBOEXPNFO BOEOPO5.%QBUJFOUT (6 men and 8 women) were included as controls. Differences between the TMD patients and control group of non-TMD patients were determined by the two-tailed t test, while multiple linear regression analysis was used to examine the correlation between AI and TOI adjusting for sex and age. Results: AI and TOI were significantly higher (P = .001 and P = .045, respectively) among TMD patients. A significant positive correlation was found between TOI and AI for the TMD group (r = 0.84, P = .01) but not for the control group. Conclusion: A positive correlation was found between TOI and AI in the myogenous TMD group. (Quintessence Int 2013;44:e141–e145)
Key words: condylar asymmetry, myogenous, opening index, TMDs
Endfeel is defined as that feeling at the end
described as passive mouth opening. The
PGUIFSBOHFPGNPUJPOPGBKPJOU#PUIFOEGFFM
temporomandibular opening index (TOI) is
and endfeel distance have been used in the
a measure of endfeel divided by the sum of
clinical examination of patients with tem-
passive and active mouth opening. This has
poromandibular disorders (TMDs).1–5
been found to differ between groups of
Mouth opening is often restricted in
TMD patients.6 It also has differentiated
TMDs. In this paper, voluntary maximum
between two subgroups of myogenous
opening is described as active mouth open-
patients, those with a TOI greater than 8%
ing, whereas opening achieved by the
and those with a TOI less than 8%.7,8
operator teasing the jaws further apart to a maximum
mouth
opening
has
been
While investigating the TOI in myogenous patients, it was noticed that patients with higher TOI values had higher condylar asymmetry index (AI) values. The AI is a
1
Senior Stomatologist, Department of Restorative Dentistry, School of Oral Health Sciences, University of the Witwatersrand,
2
3
measure of difference in left and right con-
Johannesburg, South Africa.
dylar height according to a formula devel-
Clinical Lecturer, Department of Adult Oral Health, London
oped by Habets et al.9 This index has been
Dental Institute, Barts and the London School of Medicine and
found to differ between TMD patients and
Dentistry, London, United Kingdom.
non-TMD controls in a number of stud-
Lecturer, Department of Statistics and Operations Research, School of Mathematical Sciences, Tel Aviv University, Tel Aviv, Israel.
ies,9–12 but a significant number of studies have not found any such difference in TMD groups or non-TMD groups.13–15 This sug-
4
Senior Lecturer, Department of Prosthodontics, Hebrew University-Hadassah School of Dental Medicine, Jerusalem, Israel.
gests that the AI might be a measure of adaptation rather than a sign of pathology. This variation in findings related to the AI
Correspondence: Dr Victor J. Miller, 1006D Old Lode Lane, Solihull, B92 8LJ, United Kingdom. Email:
[email protected]
in TMD vs non-TMD patients prompted the
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Q U I N T E S S E N C E I N T E R N AT I O N A L Karic et al
Table 1
Means and SD of study variables by TMD status Control
Myogenous TMD
Mean
SD
AI (%)*
4.38
1.67
9.74
5.28
Age (y)
26.65
9.78
31.36
12.35
Age range (y)
14–52
—
19–66
4.47
1.13
TOI (%)*
Mean
SD
—
5.76
1.98
4JHOJmDBOUEJGGFSFODF4% TUBOEBSEEFWJBUJPO 5.% UFNQPSPNBOEJCVMBSEJTPSEFS "* BTZNNFUSZJOEFY 50* UFNQPSPmandibular opening index.
Table 2
Multiple linear regression for condylar asymmetry *
Variable
Beta
P value
Sex
1.45
.22 .78
Age (y)
-0.01
TMD status
2.59
.02**
TOI
1.79
.00**
32 TJHOJmDBOU5.% UFNQPSPNBOEJCVMBSEJTPSEFS 50* UFNQPSPNBOEJCVMBSPQFOJOHJOEFY
present study. This pilot study compared
with only third molars missing, either natu-
UIF 50*"* SFMBUJPOTIJQ JO CPUI NZPHFOPVT
rally or through extractions, were included.
TMD and non-TMD patients and assessed
Subjects with other extracted or missing
the relationship between the two indices.
teeth were excluded. Exclusions applied to
The null hypotheses are (1) no difference
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between the two groups and (2) no correla-
tion exists between AI and TOI.
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METHOD AND MATERIALS
previously treated for a TMD. A group of 14 patients with no signs or symptoms of TMD were included in the study. The same inclu-
Fourteen patients who presented consecu-
sion and exclusion criteria applied to this
tively to the TMD clinic of the Dental Hospital,
group.
University
obtained from all patients in the study, which
of
the
Witwatersrand,
Written
informed
consent
was
Johannesburg, South Africa, diagnosed with
XBTBQQSPWFECZUIF$PNNJUUFFGPS3FTFBSDI
a
the
on
GPS
Witwatersrand, Johannesburg, South Africa.
myogenous
3FTFBSDI
TMD
according
%JBHOPTUJD
to
$SJUFSJB
5FNQPSPNBOEJCVMBS %JTPSEFST 3%$5.%
Human
Subjects,
University
of
the
All patients had a rotational panoramic
were recruited to the study. All had a full
radiograph taken by the same machine and
complement of teeth for their age. Patients
operator. The condylar asymmetry was cal-
e142
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Q U I N T E S S E N C E I N T E R N AT I O N A L Ka r i c e t a l
20.00 —
Non-TMD
Myogenous TMD
Asymmetry Index (%)
15.00 —
10.00 —
5.00 —
—
—
6.00
—
—
4.00
—
—
2.00
—
—
0.00 — 8.00
2.00
4.00
6.00
8.00
Temporomandibular Opening Index (%)
Fig 1
Association between AI and TOI by TMD status.
culated for each patient based on the
Descriptive statistical analysis was per-
method developed by Habets et al.9 The
formed to summarize the variables of inter-
investigator carrying out these calculations
est. The difference in condylar asymmetry
was not aware of patients’ diagnostic status
(AI and TOI) between the control and TMD
or TOI value.
groups was determined by the Student t
The TOI was determined by quantifying
test. Multiple linear regression analysis was
active and passive opening. To measure
used to examine the correlation between AI
active opening, each patient was asked to
and other variables (TMD status and TOI),
open their mouth to maximum voluntary
adjusting for patient age and sex. Statistical
capacity so the interincisal distance could
BOBMZTJTXBTQFSGPSNFEXJUI4144 *#.
be measured. Passive opening was determined by the clinician applying pressure at maximum opening with a finger and thumb on the maxillary and mandibular incisors to
RESULTS
establish endfeel, and the interincisal distance was measured again at this opening. The TOI was calculated as passive – active
Table 1 summarizes the means and stan-
PQFOJOHQBTTJWFø øBDUJWFPQFOJOHø¨øUP
dard deviations of the study variables by
give a percentage.6 All TOI determinations
TMD status. The control group consisted of
were carried out by the same examiner.
14 patients (6 men and 8 women), while the
#PUI 50* BOE "* NFBTVSFNFOUT XFSF DBS-
myogenous TMD group consisted of 14
ried out prior to the initiation of treatment.
patients (1 man and 13 women). The mean
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Q U I N T E S S E N C E I N T E R N AT I O N A L Karic et al
difference in AI between the control and
may be affected by age.12,18 It could be
TMD groups was 5.35%. This difference is
speculated that this may reflect the adap-
statistically significant (t = 3.62, degrees of
tive capacity of the temporomandibular joint
freedom [df> P = .001). There is also a
(TMJ) with age and the length of time that
significant difference between the groups
the joint was loaded.
concerning TOI (t = 2.10, df = 26, P = .045),
It must be noted, however, that not all
but no difference was found with regard to
studies support this view and that several
age.
IBWF GPVOE OP EJGGFSFODF CFUXFFO DPOUSPM
Table 2 summarizes the results of the
non-TMD
patients
and
TMD
patients.13
multiple linear regression. Sex and age
Some have shown differences in AI in non-
were not significantly related to condylar
TMD patients with normal occlusion.14 This
asymmetry, while TMD status (` = 2.59,
suggests that the AI may be measuring an
P = .02), and TOI (` = 1.79, P = .00) were
adaptive
significantly related to condylar asymmetry
rather than an indicator of pathology. In any
GPSUIJTNPEFM 32 = 0.713). Further
analysis
revealed
response
to
different
loading
event, although apparently useful,9–11 causignificant
interaction between TMD status and TOI.
tion should be exercised when using panoramic radiographs in this way.7
Therefore, the correlation between condylar
This study confirmed previous reports
asymmetry and TOI for each of the study
that indicated both condylar asymmetry
groups was estimated separately. There
and TOI values were higher in myogenous
was no correlation between TOI and condy-
TMD patients than in non-TMD controls. In
lar asymmetry for the control group, but for
addition, this study found a positive correla-
myogenous TMD patients, there was a sig-
tion between the TOI and the AI (P = .009)
nificant
in a group of myogenous TMD patients.
positive
correlation
(r = 0.84,
P = .000).
Such a correlation was not found among the
The association between AI and TOI in
control group (see Fig 1). This could indi-
TMD and non-TMD groups is shown in Fig 1.
cate that in this study, patients with a myogenous TMD with a higher TOI value have (and have had over time) greater levels of loading.
DISCUSSION
The increase in TOI in myogenous TMD patients may be the result of increased muscle activity, leading to increased level
The TOI is a measure of mouth opening
of pain with the resultant cocontraction of
based on a relationship between active and
muscles and a reduction of maximum vol-
passive mouth opening. It has been found
untary opening.
useful in categorizing TMD patients and is
The AI also may be a result of adapta-
also independent of age, sex, ramus length,
tion to differential loading of the TMJs. It is
and gonial angle.16 It may reflect levels of
therefore possible that muscle hyperactivity
muscle splinting via the effect of nocicep-
is involved in both AI and TOI. Myogenous
tive input on the a efferent system of the
TMD patients can be divided into those with
masticatory muscles. The TOI identifies two
a high TOI (greater than 8.0%) and a low
types of myogenous TMD patients—those
TOI (less than 8.0%). Interestingly, Visser et
with a high TOI and those with a low TOI.8
al2 have reported weak and strong muscle
A number of studies have suggested
myogenous TMD patients based on electro-
that patients with a TMD show greater AI
myography (EMG) studies of anterior tem-
than do those with no signs or symptoms of
poral and masseter muscle activity and
TMD.12,17 The AI is a measure of the differ-
postulated a functional difference between
ence in condylar height between the right
these two subgroups. Further studies utiliz-
and left condyles. In previous studies, the
ing EMG measurements and comparing
AI was found to be higher in a group of
baseline TOI with posttreatment measure-
myogenous TMD patients than in arthroge-
ments are underway. These are likely to
nous TMD patients.17 Moreover, the AI in
show possible differences in muscle hyper-
both arthrogenous and myogenous patients
activity between these two subgroups.
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VOLUME 44 t /6.#&31 t +"/6"3: 2013
Q U I N T E S S E N C E I N T E R N AT I O N A L Ka r i c e t a l
7. Van Elslande DC, Russett SJ, Major PW, Flores-
CONCLUSION
Mir C. Mandibular asymmetry diagnosis with panoramic imaging. Am J Orthod Dentofacial Orthop 2008;134:183–192.
From this study, the following conclusions
8. Miller VJ, Karic VV, Myers SL. Differences in ini-
were drawn:
tial symptom scores between myogenous TMD
t $POEZMBS BTZNNFUSZ JT IJHIFS BNPOH
patients with high and low temporomandibular
myogenous TMD patients.
opening index. Cranio 2006;24:25–28.
t The TOI is higher among myogenous
9. Habets LL, Bezuur JN, Naeiji M, Hansson TL. The
TMD patients.
Orthopantomogram, an aid in diagnosis of temporomandibular joint problems. II. The vertical sym-
t Among myogenous TMD patients, there
metry. J Oral Rehabil 1988;15:465–471.
is a positive correlation between the TOI and condylar asymmetry. Such a corre-
10. Bezuur, JN, Hansson TL, Wilkinson TM. The recognition of craniomandibular disorders—An evaluation
lation was not found among non-TMD
of the most reliable signs and symptoms when
patients.
screening for CMD. J Oral Rehabil 1989;16:367–372.
t Larger samples sizes are needed to
11. Luz JG, Miyazaki LT, Rodrigues L. Verification of the
confirm the results of this preliminary
symmetry of the mandibular ramus in patients with
study.
temporomandibular disorders and asymptomatic individuals: A comparative study [in French]. Bull Group Int Rech Sci Stomatol Odontol 2002;44:83–87. 12. Miller VJ, Myers SL, Yoeli Z, Zeltser C. Condylar
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