An analysis of the effect of buccal and lingual alveolar bone height of mandibular central incisors on crown-root ratio in normal subjects and periodontitis patients

JIANG Yong; FENG Fu-Kui; GAO Jin-Bo; LU Xu

doi:10.19749/j.cn.cjgd.1672-2973.2024.06.004

Abstract：Objective To compare and analyze the differences in mandibular central incisor's labial and lingual alveolar bone height,and their impact on the crown-to-root ratio between healthy and periodontitis patients with skeletal class Ⅰ and class Ⅱ. Methods A total of 128 elderly patients with CBCT were selected from the Stomatology Department of Tianjin Third Central Hospital from October 2021 to December 2023,and their right mandibuler central incisor teeth were selected as the study object (128 teeth in total).There are 4 groups divided,including skeletal Class Ⅰ with normal periodontium,skeletal Class Ⅱ with normal periodontium,skeletal Class Ⅰ with periodontitis,and skeletal Class Ⅱ with periodontitis,with 32 subjects (16 males and 16 females) in each group. Then,the height of labial and lingual alveolar bone,the length of crown and root of mandibular central incisors were measured by using CBCT imaging. Results Both the labial and lingual alveolar bone height of mandibular central incisors in skeletal Class Ⅰ and Class Ⅱ patients with periodontitis were significantly lower than those in normal subjects,with a more pronounced reduction on the labial side,leading to an increased crown-to-root ratio due to decreased bone height on both sides. In patients with periodontitis,the labial alveolar bone height of mandibular central incisors were significantly lower in skeletal Class Ⅱ compared to skeletal Class Ⅰ individuals,no significant difference was observed in the lingual alveolar bone height between the two classes,the increased crown-to-root ratio in skeletal Class Ⅱ may be attributed to the mandibuler labial alveolar bone height. Conclusion Skeletal facial type and periodontal disease can cause varying degrees of changes in the labial and lingual alveolar bone heights,thereby affecting the crown-to-root ratio.