Chen Xiaokang, Zeng Yiwei, Zhou Xiaolong, Hui Aiping, Hao Lanqing
Department of Stomatology, Ankang Hospital of Traditional Chinese Medicine, No. 47 Bashan East Road, Hanbin District, Ankang, 725000, Shaanxi, China.
Sci Rep. 2025 May 22;15(1):17789. doi: 10.1038/s41598-025-02705-5.
This study seeks to investigate the changes in the anatomical structure of the alveolar bone after the extraction of the mandibular second molar at 3, 6, and 12 months using cone-beam computed tomography (CBCT). This study analyzed CBCT images from 87 cases following the extraction of mandibular second molars. The anatomical structures of the alveolar bone were measured immediately after extraction, as well as at 3 months, 6 months, and 12 months post-operation. The changes in the anatomical structures of the alveolar bone corresponding to different types of alveolar bone after the extraction of mandibular second molars were also assessed. The inverted fossa type of alveolar bone was the most common, accounting for 66.6%, followed by the parallel type at 11.5% and the confluent type at 21.9%. The available buccal bone width decreased in the order of inverted fossa type, confluent type, and parallel type. The lingual mandibular fossa of the inverted fossa type was classified into three categories: Type I (48.3%), Type II (41.4%), and Type III (10.3%). Within 12 months after the extraction of the mandibular second molar, the width of the inverted fossa type and the distance between the crest and the canal had the least absorption. The lingual inclination of the alveolar bone increased. In Type I, L2, L3, and L4 were all greater than 2 mm. In Type II, L2 was less than 2 mm, while L3 and L4 were greater than 2 mm. In Type III, L2 and L3 were less than 2 mm, and L4 was greater than 2 mm. Within 12 months after the extraction of the mandibular second molar, both the height and horizontal width of the alveolar bone decreased, and the degree of decrease is correlated with the type of alveolar bone. The deeper the lingual depression, the higher the risk of mandibular nerve injury and lingual perforation. The increase in lingual inclination of the alveolar bone after extraction is a contributing factor to the risk of lingual perforation.
本研究旨在利用锥形束计算机断层扫描（CBCT）研究下颌第二磨牙拔除后3个月、6个月和12个月时牙槽骨解剖结构的变化。本研究分析了87例下颌第二磨牙拔除后的CBCT图像。在拔牙后即刻以及术后3个月、6个月和12个月测量牙槽骨的解剖结构。还评估了下颌第二磨牙拔除后不同类型牙槽骨对应的牙槽骨解剖结构变化。倒凹型牙槽骨最为常见，占66.6%，其次是平行型，占11.5%，融合型占21.9%。可用颊侧骨宽度按倒凹型、融合型和平行型的顺序减小。倒凹型的下颌舌侧窝分为三类：I型（48.3%）、II型（41.4%）和III型（10.3%）。下颌第二磨牙拔除后12个月内，倒凹型的宽度以及嵴与根管之间的距离吸收最少。牙槽骨的舌侧倾斜度增加。在I型中，L2、L3和L4均大于2mm。在II型中，L2小于2mm，而L3和L4大于2mm。在III型中，L2和L3小于2mm，L4大于2mm。下颌第二磨牙拔除后12个月内，牙槽骨的高度和水平宽度均减小，减小程度与牙槽骨类型相关。舌侧凹陷越深，下颌神经损伤和舌侧穿孔的风险越高。拔牙后牙槽骨舌侧倾斜度增加是舌侧穿孔风险的一个促成因素。
