International Campus, Tehran University of Medical Sciences (IC-TUMS), Tehran, Iran.
Dental Research Center, Dentistry Research Institute, Department of Prosthodontics, Tehran University of Medical Sciences, Tehran, Iran.
J Prosthodont. 2019 Apr;28(4):e902-e908. doi: 10.1111/jopr.12764. Epub 2018 Feb 9.
To evaluate the accuracy of a digital implant impression technique using a TRIOS 3Shape intraoral scanner (IOS) compared to conventional implant impression techniques (pick-up and transfer) in clinical situations.
Thirty-six patients who had two implants (Implantium, internal connection) ranging in diameter between 3.8 and 4.8 mm in posterior regions participated in this study after signing a consent form. Thirty-six reference models (RM) were fabricated by attaching two impression copings intraorally, splinted with autopolymerizing acrylic resin, verified by sectioning through the middle of the index, and rejoined again with freshly mixed autopolymerizing acrylic resin pattern (Pattern Resin) with the brush bead method. After that, the splinted assemblies were attached to implant analogs (DANSE) and impressed with type III dental stone (Gypsum Microstone) in standard plastic die lock trays. Thirty-six working casts were fabricated for each conventional impression technique (i.e., pick-up and transfer). Thirty-six digital impressions were made with a TRIOS 3Shape IOS. Eight of the digitally scanned files were damaged; 28 digital scan files were retrieved to STL format. A coordinate-measuring machine (CMM) was used to record linear displacement measurements (x, y, and z-coordinates), interimplant distances, and angular displacements for the RMs and conventionally fabricated working casts. CATIA 3D evaluation software was used to assess the digital STL files for the same variables as the CMM measurements. CMM measurements made on the RMs and conventionally fabricated working casts were compared with 3D software measurements made on the digitally scanned files. Data were statistically analyzed using the generalized estimating equation (GEE) with an exchangeable correlation matrix and linear method, followed by the Bonferroni method for pairwise comparisons (α = 0.05).
The results showed significant differences between the pick-up and digital groups in all of the measured variables (p < 0.001). Concerning the transfer and digital groups, the results were statistically significant in angular displacement (p < 0.001), distance measurements (p = 0.01), and linear displacement (p = 0.03); however, between the pick-up and transfer groups, there was no statistical significance in all of the measured variables (interimplant distance deviation, linear displacement, and angular displacement deviations).
According to the results of this study, the digital implant impression technique had the least accuracy. Based on the study outcomes, distance and angulation errors associated with the intraoral digital implant impressions were too large to fabricate well-fitting restorations for partially edentulous patients. The pick-up implant impression technique was the most accurate, and the transfer technique revealed comparable accuracy to it.
评估 TRIOS 3Shape 口内扫描仪（IOS）数字种植体印模技术与传统种植体印模技术（取模和转移）在临床情况下的准确性。
本研究共纳入 36 名患者，这些患者在后牙区各植入了 2 枚直径为 3.8 至 4.8 毫米的 Implantium 内连接种植体。在签署知情同意书后，使用两个印模帽将 36 个参照模型（RM）附着在口腔内，用自凝丙烯酸树脂夹板固定，通过中间部分进行切片验证，然后再次用新鲜混合的自凝丙烯酸树脂印模（Pattern Resin）通过刷珠法重新连接。之后，将带有夹板的组件附着在种植体模拟体（DANSE）上，并使用 III 型牙科石膏（Gypsum Microstone）在标准塑料模具锁托盘中进行印模。对于每种传统印模技术（即取模和转移），均制作 36 个工作模型。使用 TRIOS 3Shape IOS 进行 36 次数字印模。其中 8 个数字扫描文件损坏；28 个数字扫描文件可检索到 STL 格式。使用坐标测量机（CMM）记录 RM 和常规制作的工作模型的线性位移测量值（x、y 和 z 坐标）、种植体间距离和角位移。使用 CATIA 3D 评估软件评估数字 STL 文件，以评估与 CMM 测量相同的变量。使用 CMM 对 RM 和常规制作的工作模型进行测量，与 3D 软件对数字扫描文件进行的测量进行比较。使用广义估计方程（GEE）和可交换相关矩阵以及线性方法对数据进行统计学分析，然后使用 Bonferroni 方法进行两两比较（α=0.05）。
结果显示，在所有测量变量中，取模组和数字组之间存在显著差异（p<0.001）。在转移组和数字组之间，角位移（p<0.001）、距离测量值（p=0.01）和线性位移（p=0.03）方面存在统计学意义；然而，在取模组和转移组之间，所有测量变量均无统计学意义（种植体间距离偏差、线性位移和角位移偏差）。
根据本研究结果，数字种植体印模技术的准确性最低。根据研究结果，对于部分无牙颌患者，由于口腔内数字种植体印模相关的距离和角度误差过大，无法制作合适的修复体。取模种植体印模技术最准确，转移技术与之具有可比性。
