2017 Volume 15 Issue 3-4 Pages 114-125
We analyzed the masticatory movement patterns of patients with skeletal Class I or III malocclusion who had lateral deviations of the jaw and were treated using orthognathic surgery. The aims of this study were (1) to compare the chewing patterns at initial examination(T1), after removal of each participantʼs orthodontic appliance(T2), and after ≥1 year of maintenance(T3), and(2)to analyze the effects of different chewing patterns on changes in the axial inclination of the first molars. A Gnatho-Hexagraph III was used to measure the chewing patterns(with six degrees of freedom)of 21 participants(mean age: 23.2±5.4 years)with a menton deviation≥4 mm from the midline. A three-dimensional digital scanner was used to measure the axial inclination of the maxillary and mandibular first molars. Participants with normal chewing patterns on both the affected and unaffected sides at T1 had the same pattern at T2 and T3. In addition, 50% of the participants with reversed chewing patterns on the affected side at T1 exhibited normal patterns at T2, while 33.3% retained their original reversed pattern. Compared to the participants with normal chewing patterns, those with reversed patterns showed a significantly greater change in the inclination of maxillary and mandibular first molars on the affected side between T2 and T3. Palatal, maxillary first molar, and mandibular first molar widths showed similar results. Moreover, participants with normal chewing patterns had few changes in the buccolingual molar inclination; hence, the orientation of the molars remained unchanged.
The results showed that the axial inclination of the molars was associated with the masticatory movement pattern after orthognathic surgery, which affected molar occlusion.
This study was approved by the Ethics Committee of Nihon Universityʼs School of Dentistry at Matsudo(approval no. EC16-15-004-2)
