Abstract: Objective The purpose of this study was to investigate differences in alveolar bone of patients of skeletal Ⅲ malocclusion with different vertical facial types through measuring alveolar bone area around root, apical alveolar bone thickness and alveolar crest height in incisors’ region basing on CBCT data. Methods 110 CBCT scans of skeletal Ⅲ malocclusion with different vertical facial types were selected. Patients were categorized into three groups based on vertical facial types (GOGN-SN and FHI): long-face group (23 patients), average-face group (51 patients) and short-face group (36 patients). Buccal and lingual alveolar bone area around root (BA/LA), buccal and lingual alveolar bone thickness (BW/LW) at apical region and buccal and lingual height of alveolar crest (BH/LH) were measured and used for statistical analysis. Results In long-face group, BA and BW were significantly smaller than those in average-face group and short-face group (P＜0.001), and LW was largest among three groups (P＜0.001). BA and BW were negatively correlated with GOGN-SN, but positively correlated with FHI. LW were positively correlated with GOGN-SN, but negatively correlated with FHI. Conclusions There are differences in the amount of alveolar bone around root in the upper and lower incisors’ region in patients of skeletal Ⅲ malocclusion with different vertical-facial types. Long-face patients with skeletal Ⅲ malocclusion have smaller buccal alveolar bone area of root, smaller buccal alveolar bone thickness at apex and bigger lingual alveolar bone thickness at apex in upper and lower incisor’s region. These differences are significantly correlated with the mandibular plane angle and face-height-ratio.

Key words: skeletal III malocclusion, incisor, alveolar bone, CBCT