Post-graduate student, Department of Prosthodontics, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
Professor, Department of Prosthodontics, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
J Prosthet Dent. 2023 Jun;129(6):896.e1-896.e8. doi: 10.1016/j.prosdent.2023.03.022. Epub 2023 Apr 18.
Computer-aided design and computer-aided manufacturing (CAD-CAM) milled titanium bars have shown good clinically acceptable passive fit and definitive marginal fit; however, investigations into the passive fit and definitive marginal fit of prefabricated CAD-CAM milled titanium bars are lacking.
The purpose of this in vitro study was to compare and evaluate the passive fit and definitive marginal fit of prefabricated and conventional CAD-CAM milled titanium bars.
A total of 10 polyurethane radiopaque anatomic completely edentulous mandibular models had implants (Biohorizons) placed in the left and right canine and second premolar positions using a 3-dimensionally printed fully guided surgical guide. For the conventional bars, impressions were made, and casts were scanned and exported to a software program (exocad 3.0). For the prefabricated bars, the surgical plans were exported from the software program directly. The Sheffield test was used to evaluate the passive fit of the bars, and marginal fit was evaluated with a scanning electron microscope at ×50 magnification. The Shapiro-Wilk test was used to determine that the data were normally distributed; the data are presented using mean and standard deviation. Group comparisons were made with the independent t test (α=.05).
The passive and marginal fit of the conventional bars was better than that of the prefabricated bars. The mean ±standard deviation values for passive fit were 75.2 ±13.7 μm for conventional bars and 94.7 ±16.0 μm for prefabricated bars (P<.001). A statistically significant difference (P<.001) was also found between the marginal fit of the conventional bars 18.7 ±6.1 μm and the prefabricated bars 56.3 ±13.0 μm.
Conventional CAD-CAM milled titanium bars had a better passive and marginal fit than prefabricated CAD-CAM milled titanium bars; however, both had clinically acceptable passive fit ranging from 75.2 to 94.7 μm and definitive marginal fit ranging from 18.7 to 56.3 μm.
计算机辅助设计和计算机辅助制造（CAD-CAM）铣削钛棒已显示出良好的临床可接受的被动拟合和明确的边缘拟合；然而，预制 CAD-CAM 铣削钛棒的被动拟合和明确的边缘拟合的研究还很缺乏。
本体外研究的目的是比较和评估预制和常规 CAD-CAM 铣削钛棒的被动拟合和明确的边缘拟合。
共 10 个聚氨酯不透射线解剖完全无牙下颌模型，在左、右犬齿和第二前磨牙位置植入（Biohorizons）种植体，使用 3 维打印全导向手术导板。对于常规棒，进行印模，对模型进行扫描并导出到软件程序（exocad 3.0）。对于预制棒，手术计划直接从软件程序导出。使用谢菲尔德测试评估棒的被动拟合，使用扫描电子显微镜在 ×50 放大倍数下评估边缘拟合。使用 Shapiro-Wilk 检验确定数据是否呈正态分布；数据以平均值和标准差表示。使用独立 t 检验（α=.05）进行组间比较。
常规棒的被动和边缘拟合优于预制棒。常规棒的被动拟合的平均值±标准差为 75.2±13.7μm，预制棒为 94.7±16.0μm（P<.001）。常规棒的边缘拟合 18.7±6.1μm 和预制棒的边缘拟合 56.3±13.0μm 之间也存在统计学显著差异（P<.001）。
常规 CAD-CAM 铣削钛棒的被动和边缘拟合优于预制 CAD-CAM 铣削钛棒；然而，两者均具有临床可接受的被动拟合范围为 75.2μm 至 94.7μm，明确的边缘拟合范围为 18.7μm 至 56.3μm。
