Department of Prosthodontics, Tufts University School of Dental Medicine, Boston, Massachusetts, USA.
Department of Prosthodontics, Eastman Institute for Oral Health, University of Rochester, Rochester, New York, USA.
J Prosthodont. 2023 Jun;32(5):452-457. doi: 10.1111/jopr.13664. Epub 2023 Mar 3.
To assess the accuracy of fit of prosthesis prototypes fabricated via a complete digital workflow protocol with a reverse scan body skipping intraoral scanning for implant data acquisition.
A maxillary stone cast with four multiunit abutment implant analogs (Screw-Retained Abutments, Institut Straumann AG, Basel, Switzerland) with adequate anteroposterior spread simulated a common clinical patient situation. This stone cast served as the master cast and an interim screw-retained prosthesis was fabricated on it. Novel reverse scan bodies were connected to the interim prosthesis, and extraoral scanning was performed with a white light intraoral scanner. The produced standard tessellation language (STL) files were then imported to computer-assisted design software and after the digital design, the STL file was exported to a computer-assisted machining milling machine and a three-dimensional (3D) printer to produce a total of 50 milled and 50 printed fixed complete denture prototypes, respectively. Two clinicians assessed the accuracy of fit of each digitally fabricated prosthesis prototype on the master cast, utilizing the screw-resistance test and radiographic evaluation. Out of the 100 prototypes, 94% (94/100) were fitting accurately. Fisher's exact test was used to test the difference among the groups. The test revealed statistically significant results (p = 0.027).
Out of the 50 digitally fabricated milled prosthesis prototypes, 50 (100%) presented with accurate fit under in vitro assessment. Out of the 50 digitally fabricated 3D printed prototypes, 44 (88%) presented with accurate fit under in vitro assessment.
Accurately fitting digitally fabricated prosthesis prototypes can be milled after extraoral scanning with reverse scan bodies without intraoral implant data acquisition.
评估通过完整的数字化工作流程协议制造的假体原型的拟合精度，该协议跳过口内扫描获取种植体数据，使用反向扫描体进行口外扫描。
带有四个多单位基台种植体模拟体（螺丝固位基台， Institut Straumann AG，巴塞尔，瑞士）的上颌石模型，具有足够的前后扩展，模拟常见的临床患者情况。该石模型用作母模，并在其上制作临时螺丝固位修复体。新型反向扫描体连接到临时修复体上，并使用白光口内扫描仪进行口外扫描。生成的标准三角测量语言 (STL) 文件随后被导入计算机辅助设计软件，在数字化设计后，将 STL 文件导出到计算机辅助加工铣床和三维 (3D) 打印机，分别制作 50 个铣削和 50 个打印的固定全口义齿原型。两位临床医生在母模上评估每个数字化制造修复体原型的拟合精度，使用螺丝阻力测试和放射评估。在 100 个原型中，94%（94/100）的拟合精度准确。使用 Fisher 精确检验测试组间差异。该检验显示具有统计学显著差异（p=0.027）。
在体外评估中，50 个数字化铣削修复体原型中有 50 个（100%）的拟合精度准确。在体外评估中，50 个数字化 3D 打印原型中有 44 个（88%）的拟合精度准确。
在不获取口内种植体数据的情况下，使用反向扫描体进行口外扫描后，可以铣削准确拟合的数字化制造修复体原型。
