Study on the posterior teeth mesiodistal tipping degree of normal occlusion subjects among different facial growth patterns / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the relationship between the mesiodistal tipping degree of maxillary and mandible posterior teeth and different vertical facial skeletal types of subjects with normal occlusion.</p><p><b>METHODS</b>163 subjects with normal occlusion were selected, lateral cephalograms were taken and divided into three different facial skeletal types. The difference of the mesiodistal tipping degrees and intersection angles of upper and lower posterior teeth between the three different facial skeletal types were analyzed.</p><p><b>RESULTS</b>Among 163 subjects, vertical growth pattern, average growth pattern and horizontal growth pattern were 24, 96 and 43 respectively. There were statistic differences of mesiodistal tipping degrees of the first and second maxillary and mandible premolar and the first permanent molar between vertical growth and horizontal growth pattern, horizontal growth and average growth pattern (P < 0.05). But there were no statistically significant differences between vertical growth and average growth pattern (P > 0.05). The differences of the maxillary and mandible posterior teeth's intersection angle among three vertical facial skeletal types had no statistic significance (P > 0.05).</p><p><b>CONCLUSION</b>Different vertical facial skeletal type has its own normal and coordinated posterior teeth mesiodistal tipping degrees.</p>

Morphological characteristics of mandibular symphysis in adult skeletal class II and class III malocclusions with abnormal vertical skeletal patterns / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To figure out the differences of the morphological characteristics of mandibular symphysis between Class II and Class III adult skeletal malocclusions with different abnormal vertical skeletal patterns.</p><p><b>METHODS</b>109 Chinese female adults of skeletal Class II and Class III were chosen and divided into four groups according to vertical and sagittal skeletal pattern: Class II--vertical-growth-pattern group (n=30), Class III--vertical-growth-pattern group (n=25), Class II--horizontal-growth-pattern group (n=29), Class III--horizontal-growth-pattern (n=25). Lateral cephalograms were taken. The symphyseal widths and heights, along with lower incisor positions were evaluated. Observation and statistics analysis were done to clarify the morphological characteristics of the symphyseal region of different skeletal patterns.</p><p><b>RESULTS</b>There were morphological differences of symphyseal region between Class II and Class III skeletal malocclusions, but not significant in width and total height. With a vertical-growth-pattern, Class II malocclusions had higher alveolus than Class III, but smaller chin prominence and lower basal bone (P < 0.01). With a horizontal-growth-pattern, Class II malocclusions had higher alveolus (P < 0.05) and larger alveolar top width (P < 0.001). With a same sagittal skeletal pattern, vertical-growth-pattern group had thinner but higher symphyseal region and bigger chin prominence (P < 0.001 in Class II while P < 0.05 in Class III). Besides, a vertical-growth-pattern malocclusion was prone to have a cucurbit-morph chin, of which Id width was larger than basal width (P < 0.01).</p><p><b>CONCLUSION</b>There are morphological differences in symphyseal region between Class II and Class III skeletal malocclusions with different abnormal vertical skeletal patterns. The influence of abnormal vertical skeletal pattern to symphyseal morphological characteristics is greater than that of abnormal sagittal skeletal pattern. There is a risk of orthodontic movement of low incisors in vertical-growth-pattern skeletal malocclusion.</p>