Graduate student, Department of Prosthodontics, College of Dentistry, Yonsei University, Seoul, Republic of Korea.
Assistant Professor, Dongnam Health University, Suwon-si, Gyeonggi-do, 16328, Republic of Korea.
J Prosthet Dent. 2018 Nov;120(5):693-698. doi: 10.1016/j.prosdent.2018.01.012. Epub 2018 May 25.
Rapid prototyping, including stereolithography (SLA), is a more recent technique for fabricating metal frameworks than the conventional lost-wax technique. However, investigations of the marginal discrepancies and internal spacing of cobalt-chromium (Co-Cr) metal copings fabricated using SLA are lacking.
The purpose of this in vitro study was to evaluate the clinical acceptability of the marginal discrepancies and internal spacing of Co-Cr metal copings fabricated using the SLA technique.
A resin tooth of a maxillary right first premolar was prepared with a deep chamfer margin for a metal-ceramic crown. Titanium master dies were milled after scanning the prepared tooth (n=45). In conventional lost wax group (group LW), the conventional lost-wax technique was used to fabricate Co-Cr metal copings (n=15). In milling group (group MC), a computer-aided design (CAD) system was used to design the metal copings, which were milled from Co-Cr alloy (n=15). The CAD system was also used to design the metal copings in a 3D-printed group (group SL), and Co-Cr metal copings were cast from resin patterns fabricated using the SLA device (n=15). Marginal discrepancies and internal spaces were measured using an optical microscope at ×100 magnification at 11 reference points. The values were analyzed statistically with 1-way analysis of variance (α=.05).
The mean (±SD) overall space was 63.2 ±16.6 μm for group LW, 70.2 ±15.5 μm for group SL, and 130.3 ±13.8 μm for group MC. The overall spaces differed significantly between group MC and the other 2 groups (P<.05). The marginal discrepancy and internal spaces were significantly larger in group MC than in groups LW and SL. (P<.05). Occlusal spaces differed significantly among the 3 study groups (P<.05).
Co-Cr metal copings fabricated using an SLA technique showed clinically acceptable marginal discrepancies and internal spaces. These spaces did not differ significantly from those obtained with the conventional lost-wax technique.
快速原型制作，包括立体光固化成型（SLA），是一种比传统失蜡技术更先进的制造金属框架的技术。然而，对于使用 SLA 制造的钴铬（Co-Cr）金属冠的边缘差异和内部间距的研究还很少。
本体外研究的目的是评估使用 SLA 技术制造的 Co-Cr 金属冠的边缘差异和内部间距的临床可接受性。
用深倒角边缘制备上颌右第一前磨牙的树脂牙，用于金属陶瓷冠。扫描准备好的牙齿后，铣削钛金母模（n=45）。在传统失蜡组（组 LW）中，采用传统失蜡技术制造 Co-Cr 金属冠（n=15）。在铣削组（组 MC）中，使用计算机辅助设计（CAD）系统设计金属冠，并用 Co-Cr 合金铣削而成（n=15）。CAD 系统还用于设计使用 SLA 设备制造的树脂图案的 3D 打印组（组 SL）中的金属冠，并从树脂图案中铸造 Co-Cr 金属冠（n=15）。在光学显微镜下以 100 倍放大率在 11 个参考点测量边缘差异和内部空间。使用单向方差分析（α=.05）对值进行统计分析。
LW 组的总间隙平均值（±SD）为 63.2±16.6μm，SL 组为 70.2±15.5μm，MC 组为 130.3±13.8μm。MC 组与其他两组之间的总间隙差异有统计学意义（P<.05）。MC 组的边缘差异和内部空间明显大于 LW 组和 SL 组（P<.05）。（P<.05）。3 个研究组的牙合间隙差异有统计学意义（P<.05）。
使用 SLA 技术制造的 Co-Cr 金属冠具有临床可接受的边缘差异和内部空间。这些空间与传统失蜡技术获得的空间没有显著差异。
