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研究目的:观察人类上颌中切牙拔除后牙槽骨外形改建的规律。创新要点:锥形束计算机断层摄影(CBCT)在口腔硬组织测量方面具有可靠性,在不同时期拍摄的影像中测量具有可重复性。本研究充分利用这一影像学工具观察人类上颌中切牙拔除后牙槽骨改建的规律。研究方法:选择40名患者上颌中切牙拔牙前和拔牙后三个月时拍摄的两份CBCT影像资料。在第一次CBCT中,选取中切牙拔牙窝深、中、浅三个水平断层进行矢状断层重建,分别记录矢状断层起点到拟拔除中切牙(实验牙T)牙髓中心移动的层数,并测量实验牙T处牙槽骨宽度,在中切牙拔牙窝中层测量腭平面相关垂直距离。在第二次CBCT的三个水平断层上,依据第一次记录的移动层数定位实验牙T,并在定位处测量牙槽骨宽度。在中切牙拔牙窝中层上转移第一次CBCT记录的腭平面相关距离,并测量唇腭侧牙槽嵴顶沿原牙根外形垂直吸收的距离。重要结论:上颌中切牙拔除后三个月,在拔牙窝的不同深度,唇侧的牙槽骨均有不同程度的水平骨吸收,越接近牙槽嵴顶处牙槽骨吸收越明显。唇腭侧牙槽嵴顶均有明显的垂直骨吸收,唇侧牙槽嵴顶的垂直骨吸收比腭侧明显。
The purpose of this study was to observe the regularity of alveolar bone remodeling after human maxillary central incisor extraction. Key innovations: Cone beam computed tomography (CBCT) is reliable in the measurement of oral hard tissue and repeatability in images taken at different times. This study made full use of this imaging tool to observe the remodeling of alveolar bone after human maxillary central incisor extraction. METHODS: Two CBCT images of 40 patients with maxillary central incisors before tooth extraction and three months after tooth extraction were selected. In the first CBCT, three deep, middle and shallow horizontal incisions were selected for sagittal reconstruction. The starting point of sagittal cut to the center of the endodontic tooth was extracted from the central incisor (experimental tooth) The number of layers and the width of the alveolar bone at T were measured. The vertical distance of the palatal plane was measured in the middle layer of the middle and distal tooth extraction. On the third horizontal slice of the CBCT, the experimental tooth T was located on the first recorded moving layer and the alveolar bone width was measured at the location. The first CBCT recorded palatal-related distances were recorded on the middle of the deciduous tooth extraction socket and the vertical absorption distance along the original root profile of the alveolar cleft palate was measured. Important conclusion: Three months after the extraction of the maxillary central incisor, different degrees of horizontal bone resorption were found in the alveolar bone at different depths and on the labial side. The more the alveolar bone absorbed, the closer the alveolar crest was. The maxillary alveolar ridge had obvious vertical bone resorption, and the vertical bone resorption on the labial alveolar ridge was more obvious than that on the palatal side.