Graduate student, Department of Prosthodontics, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea.
Professor, Department of Prosthodontics, School of Dentistry, A3DI, Kyungpook National University, Daegu, Republic of Korea.
J Prosthet Dent. 2017 Aug;118(2):208-215. doi: 10.1016/j.prosdent.2016.10.030. Epub 2017 Jan 12.
The fit of interim crowns fabricated using 3-dimensional (3D) printing is unknown.
The purpose of this in vitro study was to evaluate the fit of interim crowns fabricated using photopolymer-jetting 3D printing and to compare it with that of milling and compression molding methods.
Twelve study models were fabricated by making an impression of a metal master model of the mandibular first molar. On each study model, interim crowns (N=36) were fabricated using compression molding (molding group, n=12), milling (milling group, n=12), and 3D polymer-jetting methods. The crowns were prepared as follows: molding group, overimpression technique; milling group, a 5-axis dental milling machine; and polymer-jetting group using a 3D printer. The fit of interim crowns was evaluated in the proximal, marginal, internal axial, and internal occlusal regions by using the image-superimposition and silicone-replica techniques. The Mann-Whitney U test and Kruskal-Wallis tests were used to compare the results among groups (α=.05).
Compared with the molding group, the milling and polymer-jetting groups showed more accurate results in the proximal and marginal regions (P<.001). In the axial regions, even though the mean discrepancy was smallest in the molding group, the data showed large deviations. In the occlusal region, the polymer-jetting group was the most accurate, and compared with the other groups, the milling group showed larger internal discrepancies (P<.001).
Polymer-jet 3D printing significantly enhanced the fit of interim crowns, particularly in the occlusal region.
使用三维（3D）打印制作的临时冠的适合度未知。
本体外研究的目的是评估使用光聚合喷射 3D 打印制作的临时冠的适合度，并将其与铣削和压缩成型方法进行比较。
通过对下颌第一磨牙的金属母模进行印模制作 12 个研究模型。在每个研究模型上，使用压缩成型（成型组，n=12）、铣削（铣削组，n=12）和 3D 聚合物喷射方法制作临时冠（N=36）。冠的制备如下：成型组，采用重叠印模技术；铣削组，使用 5 轴牙科铣床；聚合物喷射组，使用 3D 打印机。使用图像叠加和硅橡胶复制技术评估临时冠在近中、边缘、内部轴向和内部咬合区域的适合度。使用 Mann-Whitney U 检验和 Kruskal-Wallis 检验比较组间结果（α=0.05）。
与成型组相比，铣削组和聚合物喷射组在近中和边缘区域的结果更准确（P<.001）。在轴向区域，尽管成型组的平均差异最小，但数据显示偏差较大。在咬合区域，聚合物喷射组最准确，与其他组相比，铣削组显示出更大的内部差异（P<.001）。
聚合物喷射 3D 打印显著提高了临时冠的适合度，特别是在咬合区域。
