2018 Volume 81 Issue 1 Pages 11-15
We analyzed serial time measurements of occlusal forces with movement from habit ual occlusal position to intercuspal position in healthy volunteers (HV) and volunteers with tem poromandibular disorders (TMD). The participants were 20 healthy volunteers and 42 volunteers with TMD. We defined the occlusion time (OT) as the duration from 2% to 90% of maximum vol untary contraction during intercuspation. The indicator of premature occlusal contacts was estab lished as the percentage of the occlusal force of the premature occlusal contacts (DELTA) di vided by the occlusal force during maximum intercuspal contraction (DELTA%). The median OT for HV and TMD were 0.36 and 0.61 sec, respectively (p＜0.01). The median DELTA% for HV was 2.7%. It was 3.9% for TMD when OT was less than 0.7 sec, and 8.3% for TMD when OT was greater than 0.7 sec (p＜0.01). Multiple comparisons indicated a significant difference be tween HV and TMD when OT was greater than 0.7 sec (p＜0.01). There was also a significant difference between TMD when OT was less than 0.7 sec, and TMD when OT was greater than 0.7 sec (p＜0.05). DELTA is detected when the mandible is displaced in the horizontal plane by interference of premature occlusal contact. The longer OT of TMD when OT was greater than 0.7 sec may have been caused by a complex mandibular displacement of rotation and transla tion. Shika Igaku (J Osaka Odontol Soc) 2018 ;Mar ;81(1) : 11-15.
