The effect of the gonial angle, ramus length, age and gender on the temporomandibular opening index
Date
2014-05-30
Authors
Moipolai, Pusetso
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Abstract
Disorders of the temporomandibular joint (TMD) are the most common
chronic pain conditions in the dental population. The cardinal signs and
symptoms of these disorders are pain in orofacial muscles and / or joints;
joint sounds; and limitation o f mandibular movement.
Limitation of mandibular movement is usually assessed by measuring
linear mouth opening. However, this has a number o f limitations. It is
dependent on variables such as age, gender and ramus length. A new
measure o f movement was therefore developed, the temporomandibular
opening index, which was found, in a limited study to be independent of
age and gender.
In this study, several variables - age., gender, gonial angle and ramus
length - were studied to determine their effect, on the temporomandibular
opening index. This temporomandibular opening index was determined as
a ratio between active (voluntary) and passive mouth opening (Miller et
al., 1999).
Forty-two subjects who did not exhibit signs and symptoms o f TMD were
recruited to the study.
Ramus length, gonial angle, gender, and age were tested for association
with the temporomandibular opening index. Linear regression analysis
showed that there was no evidence o f a relationship between the TOI and
any o f the variables tested. The analysis showed that the
temporomandibular opening index was not dependent on gender
(p>0.644); gonial angle (p>0.327); ramus length (p>0.248) and age
(p>0.690).
This suggests that, as the temporomandibular opening index is also
independent o f both age and gender, it is a better indicator o f limitation of
oral opening than linear mouth opening measurements. In addition, it can
also be used to categorise TMD patients. It is a cost effective, simple aid
in the diagnosis o f these disorders.