The Matching Of Dental And Basal Bone Arch And The Compensatory Mechanism Of Skeletal Classâ…¡ Malocclusion

ObjectiveThe aim of this article is to study the characteristics and matching of dental and basal bone arch forms, axis of teeth and compensatory mechanism of skeletal Class II malocclusion and to provide references for diagnosis and clinical treatment plan.Methods50subjects with normal occlusion individuals and51subjects with skeletal Class II malocclusion individuals were selected and captured images by CBCT to measure the maxillary and mandibular dental and basal bone arch widths,depths and tooth axis with Mimics10.01. Corresponding measurement differences of upper and lower jaws were also calculated. Independent samples t-test was employed for comparison of the two groups.Results1.Comparison of dental arch measurements items:In the skeletal Class II sample compared with the normal occlusion individuals sample the widths of first premolar and first molar was found to be significantly narrower, the depths have an increase tendency but was not significantly different.2.Comparison of basal bone arch measurements items:In the skeletal Class II sample compared with the normal occlusion individuals the width of anterior basal bone arch was found to be significantly narrower, the depths have an increase trend but decrease in the mandibular, significant difference was found in the maxillary second molars and mandibular lateral incisor.3.Comparison of corresponding measurements differences of maxillary and mandibular items:In the skeletal Class II sample compared with the normal occlusion individuals the widths difference between maxillary and mandibular of dental arch and basal bone were found reduced, significant difference was found in the maxillary premolar,first molar and second molar. The depths were found increases,significant difference was found in the maxillary first molar. 4.Comparison of teeth axis:In the skeletal Class II sample compared with the normal occlusion individuals the significant differences of lingual inclination were found in maxillary second premolar and second molar, significant differences of buccal inclination were found in mandibular first premolar first molar and second molar. Significant differences of mesial inclination were found in maxillary second premolar and second molar.Conclusions1.In the skeletal Class II sample compared with the normal occlusion individuals sample the maxillary dental arch have a narrower and longer tendency, the maxillary anterior basal bone arch was narrow and long, the mandibular anterior basal bone arch was narrow and short.2.1n the skeletal Class II sample compared with the normal occlusion individuals sample the maxillary and mandibular disharmony was found in both dental arch and basal bone arch in the transverse and the disharmony was found in the basal bone arch in the sagittal.3.In the skeletal Class II sample compared with the normal occlusion individuals maxillary posterior teeth were lingual inclination, mandibular posterior teeth were buccal inclination..