Analysis of the Relationship between the Vertical Facial Pattern of the Skeletal Class Ⅲ Malocclusion and the Characteristics of Alveolar Bone of Incisor Based on the Findings of Cone Beam Computed Tomography

XIE Lili; ZHANG Hao; ZHAO Wenlong; LI Liguo; CHU Danyang

doi:10.3639/i.issn.2095-3097.2025.01.016

Abstract：Objective To analyze the correlation of the vertical facial pattern of the skeletal Class Ⅲ malocclusion with the quantity of alveolar bone and cortical bone density of incisor based on the findings of cone beam computed tomography(CBCT),and provide a basis for clinical correction design.Methods Sixty patients with skeletal Class Ⅲ malocclusion admitted to the Department of Stomatology,Hebei Provincial People's Hospital from March 2021 to March 2024 were selected.According to the FMA angle,or frankfort-mandibular plane angle(FH-MP),they were divided into the short facial pattern group(n=23),the average facial pattern group(n=22),and the long facial pattern group(n=15).CBCT was used for scanning and reconstruction,and the reconstructed images were measured and analyzed by Materialise Mimics 21 software.The buccal/labial alveolar bone area(BA/LA)around the incisor roots,the buccal/labial alveolar crest height(BH/LH)of the incisors,the buccal/labial alveolar bone thickness(BW/LW)at the incisor apical,and the cortical bone density at the root of the upper and lower incisors(HU)were compared and analyzed among the three groups.Results The BA of upper and lower incisors in the long facial pattern group was significantly smaller than that in the short facial pattern group and the average facial pattern group(P<0.05).The LA of maxillary lateral incisors in the long facial pattern group was significantly smaller than that in the short facial pattern group and the average facial pattern group(P<0.05),while there was no significant difference in other LAs among the three groups(P>0.05).The BH of mandibular lateral incisors in the average facial pattern group was significantly higher(P<0.05),while there were no significant differences in LA and LH of other incisors among the three groups(P>0.05).The BW of upper and lower incisors in the long facial pattern group was significantly smaller than that in the short facial pattern group and the average facial pattern group(P<0.05).The cortical bone density of the upper and lower incisors in the long facial pattern group was significantly lower than that in the short facial pattern group and the average facial pattern group(P<0.05).BA,BW,and cortical bone density of the upper and lower incisors were negatively correlated with FMA(P<0.05),while the LA of maxillary incisor was negatively correlated with FMI(P<0.05).The LW of mandibular lateral incisor was negatively correlated with FMA(P<0.05).Conclusion There are differences in the morphological characteristics of the alveolar bone around the root of the incisor in patients with skeletal Class Ⅲ malocclusion of different vertical plane types.The area of alveolar bone on the buccal side of the incisors,the thickness of alveolar bone on the buccal side of the root apex,and the cortical density of the root bone are all relatively small in patients with a long facial pattern,which is closely related to FMA.