Kaori Ishii

Relationship between molar occlusion and masticatory movement in lateral deviation of the mandible

Introduction: The relationship between molar occlusion and chewing patterns was examined in subjects with laterally deviated mandibles. Methods: Twenty‐three patients with mandibular deviation from the midline (4 mm or more) and skeletal Class I (0° ≤ANB ≤4°) were divided into 2 groups: normal bite and crossbite. The chewing pattern was classified as normal, reversed, or crossover. Results: The normal bite group had a normal chewing pattern on the affected side 100% of the time and a reversed chewing pattern on the affected and unaffected sides 0% and 7.2% of the time, respectively. Additionally, the normal bite group showed no evidence of a crossover chewing pattern and also had significantly less axial inclination of the mandibular teeth on the affected side compared with the crossbite group; lingual inclination was also evident. The crossbite group had a normal chewing pattern on the affected and unaffected sides 0% and 55.6% of the time, respectively, and reversed and crossover chewing patterns on the affected side 55.6% and 44.4% of the time, respectively. Conclusions: A normal chewing pattern tends to result in lingual axial inclination of the mandibular molars on the affected side, as well as a more consistent chewing pattern. HighlightsChewing was classified into 3 patterns: normal, reversed, and crossover.Subjects with normal bite had a normal chewing pattern.Compared with the crossbite group, the normal bite group had less axial inclination of mandibular teeth on the affected side.Subjects with normal bite had lingually inclined molars on the affected side.Normal chewing pattern may cause lingual inclination on the affected side and more consistent chewing patterns.

The long-term study about changes in hard and soft tissues and the position of the tongue at speech after postorthognathic surgery

The purpose of this study was to investigate factors that may influence the position of the tongue during speech by the use of acoustic analysis. The subjects were 21 patients diagnosed with mandibular prognathism who had undergone a sagittal split ramus osteotomy. The formants of / R / were analyzed before operation (BO), one month after operation (AO1m), and one year after operation (AO1y). To divided into 2 groups, F1/ F04 and F2/F04 of the control, and at the time of AO1y they were compared. These are the cases within the standard formants of AO1y (improved group), and cases over 1S.D. formants of AO1y (nonimproved group). The cephalometric analysis of each group was compared as well as the correlation between the formants and the cephalometric values. The results were as follows:

Clinical application of acoustic analysis in evaluation of tongue function

conditions. The results of adhesive paste comparisons with different consistencies showed that adhesives with lower filler levels produced significantly higher SBS than those with higher levels. No statistically significant differences in SBS were observed under the various bracket-pressing force or pressing-time conditions. Conclusion: Under the described test conditions, when a bracket with a plastic base was bonded using an adhesive paste containing an S-PRG filler, clinically acceptable SBS could be obtained by bonding with a relatively weak force, for a short period.