Gallucci German O, Belser Urs C, Bernard Jean-Pierre, Magne Pascal
Department of Prosthodontics, School of Dental Medicine, University of Geneva, Switzerland.
Int J Periodontics Restorative Dent. 2004 Feb;24(1):19-29.
This study evaluated the dimensions and characteristics of the cementoenamel junction (CEJ) of maxillary anterior teeth; the natural CEJ was compared to current implant design and used for design optimization. Standardized digital images of 137 extracted human teeth (45 central incisors, 46 lateral incisors, and 46 canines) were used to measure cervical dimensions, CEJ curvature, and distance from zenith of CEJ to interdental contact on proximal views. The x- and y-coordinates of the CEJ contour were digitized before mathematic processing to allow the representation of a single average curve for buccal, palatal, mesial, and distal surfaces for each tooth type. These measurements were combined to existing data related to dentogingival and "implantomucosal" junction to extrapolate specific biologic landmarks around teeth and implants. Mean cervical dimensions, distance from zenith of CEJ to interdental contact, and CEJ curvature were compared. Cervical dimensions significantly differed, with a more symmetric cervical cross-section for central incisors, slightly more rectangular shape for lateral incisors, and distinctly rectangular shape for canines. CEJ curvature was statistically different between all tooth groups (centrals > laterals > canines); within groups, curvature value was always superior at the mesial aspect compared to distally (3.46 mm vs 3.13 mm for centrals, 2.97 mm vs 2.38 mm for laterals, and 2.55 mm vs 1.60 mm for canines). Tooth-implant biologic width discrepancies ranged from 4.10 to 5.96 mm and were different between all groups of teeth (centrals > laterals > canines); within groups, the discrepancy was always superior at the mesial aspect compared to distally. Current implant design featuring a flat, rotation-symmetric shoulder should be reconsidered in view of natural CEJ contour to improve biologic considerations and related esthetics.
本研究评估了上颌前牙牙骨质釉质界（CEJ）的尺寸和特征；将天然CEJ与当前种植体设计进行比较，并用于设计优化。使用137颗拔除的人类牙齿（45颗中切牙、46颗侧切牙和46颗尖牙）的标准化数字图像来测量颈部尺寸、CEJ曲率以及在近中视图上从CEJ顶点到牙间接触点的距离。在进行数学处理之前，将CEJ轮廓的x和y坐标数字化，以便为每种牙型的颊面、腭面、近中面和远中面表示一条单一的平均曲线。将这些测量结果与现有的与牙-牙龈和“种植体-黏膜”界相关的数据相结合，以推断牙齿和种植体周围的特定生物学标志。比较了平均颈部尺寸、从CEJ顶点到牙间接触点的距离以及CEJ曲率。颈部尺寸存在显著差异，中切牙的颈部横截面更对称，侧切牙略呈长方形，尖牙则明显呈长方形。所有牙组之间的CEJ曲率在统计学上存在差异（中切牙＞侧切牙＞尖牙）；在各牙组内，近中面的曲率值始终高于远中面（中切牙分别为3.46 mm和3.13 mm，侧切牙分别为2.97 mm和2.38 mm，尖牙分别为2.55 mm和1.60 mm）。牙-种植体生物学宽度差异在4.10至5.96 mm之间，且在所有牙组之间存在差异（中切牙＞侧切牙＞尖牙）；在各牙组内，近中面的差异始终高于远中面。鉴于天然CEJ轮廓，应重新考虑当前具有平坦、旋转对称肩部的种植体设计，以改善生物学考量及相关美学效果。
