Comparative study of the temporomandibular joint space in maximum intercuspation and canine edge-to-edge positions in deep bite and non-deep bite subjects
S. Minagi et al., Comparative study of the temporomandibular joint space in maximum intercuspation and canine edge-to-edge positions in deep bite and non-deep bite subjects, J ORAL REH, 27(6), 2000, pp. 517-521
In order to study the relationship between morphological properties of the
TMJ and the mathematically predicted force distribution in the TMJ, the geo
metric distribution of the joint space on top of the condylar surfaces was
evaluated. Seven deep bite subjects and seven non-deep bite subjects were u
sed, and the joint space in the maximum intercuspation and canine edge-to-e
dge positions was analysed in each group. Standardized images of the TMJ we
re taken with computed tomography (CT) using a mandible positioner. The com
parative ratio of joint space (CRJS) between the maximum intercuspation and
the canine edge-to-edge positions was calculated and summarized on the map
of the mean morphological outline of the condyle. On the balancing-side co
ndyle, the CRTS of small value was distributed mainly on the anterior edge
of the condyle in the non-deep bite group, whereas, in the deep bite group,
it was distributed on the centre of the condyle. On the working-side condy
le, the small CRJS was distributed around the lateral pole of the condyle i
n the non-deep bite group, whereas, in the deep bite group, it was found ar
ound the posterior part of the condyle. The distribution pattern of CRJS on
the upper surface of the condyle in the non-deep bite group was consistent
with the results of previous studies on mathematical simulation of TMJ loa
ding. From the results of this study, it was suggested that the distributio
n of mechanical loading on the TMJ in the eccentric mandibular position wou
ld be highly affected by the comparative ratio of joint space. As the compa
rative ratio of joint space would be highly affected by the condylar positi
on, the analysis of the morphology of the TMJ in relation to mechanical joi
nt loading, in a future investigation, should be carried out on specific ma
ndibular positions in relation to the function of the TMJ to be studied.