Measurement Of Maxillary Central Incisor Tooth Root And Alveolar Bone By Cone Beam Computed Tomography And Its Clinical Significance

Objective: This study was to classify the relationship of the root positions of the maxillary central incisor and measure the thickness of the facial bone wall at different locations using cone beam computed tomography(CBCT). The purpose of this study was to provide for clinical reference before implant immediately.Methods: CBCT data of the maxillary central incisors of 934 cases was selected from the department of radiology in Longgang Center Hospital. The relationship of the root positions of the maxillary central incisor was classified using CBCT and the thickness of the facial bone wall was measured at different locations. Three aspects were measured: at the 4 mm apical to the cemento-enamel junction(CEJ), the middle of the root and the apical.Results: The differences with the alveolar bone of the maxillary incisor root position were significant. Most of the maxillary incisors(95.4%) were positioned more buccally(B), 4.4% were positioned more midway(M) and 0.2% were more palatally(P). The thickness of bucal bone and palatal bone were gradually thicker from crown to root. The mean thickness of the labial bone was 0.81 ± 0.33 mm ~ 1.76 ± 0.84 mm and the palatal bone was 1.59 ± 0.71 mm ~ 7.65 ± 2.26 mm. According to the traditional classification, the thickest of labial bone was B and the thickness of labial bone was 0.78 ± 0.36 mm ~ 1.72 ± 0.92 mm. The thickness of palatal bone was 0.82 ± 0.12 mm ~ 4.12 ± 2.21 mm. In the average thickness of the partial palatal CEJ under 4 mm, the thickest was 1.28 ± 0.37 mm. In the average thickness of the partial buccal apical, the thicknest was 7.50 ± 2.47 mm. The sagittal buccal type was further classified into three subtypes subtypes I, II, and III, respectively. In the buccal type, 47.5%, 44.2%, and 8.3% were subtypes I, II, and III, respectively. In the thickness of labial bone wall, the thickest was buccal subtype I(range 0.76 ± 0.42 mm to 1.82 ± 0.86 mm). In the thickness of palatal bone wall, the thinest was buccal subtype III(range0.62 ± 0.27 mm to 4.97 ± 2.17 mm) and the thickness of buccal subtype I was 1.11 ± 0.75 mm ~ 8.87 ± 3.01 mm. The thickness of buccal or palatal did differ significantly between the men and women(P<0.05). The thickness of male palatal bone wall was thicker than women.Conclusion: 1.Most of the maxillary central incisors were positioned more buccally(95.4%) and the thickness of male palatal bone wall was 0.78 ~ 5.89 mm;2. Using CBCT assess the three-dimensional position of the root and measure the thickness of bucal-palatal bone wall is necessary to plan the implant site for immediate placement in the maxillary esthetic zone.