In general, orthodontists make problem lists and treatment plans based on norms of several cephalometric ´standards, ´But consideration of dentoalveolar compensation, which tends, to maintain normal dental arch relationship in various skeletal jaw relationships, helps orthodontists make more individualized treatment objectives and plans.
The purpose of this study was to classify skeletal patterns of normal occlusion samples by cluster analysis and to investigate the dentoalveolar compensation according to skeletal patterns. The subjects were consisted of 125 subjects who were normal occlusion samples at Seoul National University Dental Hospital, Department of Orthodontics. Lateral cephalograms in centric occlusion were traced and digitized. The skeletal patterns of normal occlusion samples were classified into three horizontal groups and three vertical groups by cluster analysis and ANOVA on the skeletal and dentoalveolar measurements among the groups were carried out.
The results were as follows ;
1. Anteroposterior and vertical skeletal relationships of normal occlusion samples were very variable.
2. As the mandibular position was anterior to the maxilla, the maxillary incisors inclined more labially, the mandibular
incisors more lingually, and the occlusal plane was flattened due to the anteroposterior dentoalveolar compensation. 3. As the vertical skeletal pattern was prominent, the upper anterior dentoalveolar height was increased, the lower posterior
dentoalveolar height was decreased and upper posterior teeth was uprighted to the palatal plane and lower incisors and
lower posterior teeth to the mandibular plane.
4. Lower incisors were more strongly associated with the dentoalveolar compensation than upper incisors according to the anteroposterior and vertical skeletal relationship.
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