Schwindling Maria, Herpel Christopher, Schwindling Franz Sebastian, Kapferer-Seebacher Ines, Vogel Lorenz, Steiner René
University Hospital for Cranio-maxillofacial and Oral Surgery, Medical University of Innsbruck, Innsbruck, Austria.
Department of Prosthetic Dentistry, Heidelberg University Hospital, Heidelberg, Germany.
J Dent. 2025 Oct;161:105986. doi: 10.1016/j.jdent.2025.105986. Epub 2025 Jul 22.
To evaluate the accuracy of 3D-printed models and positional trueness of the removable dies.
A typodont incisor, canine, premolar, and molar were prepared for single crowns and digitized. Based on this scan, two sets of models (n = 10 each) were 3D-printed in two milling centers, resulting in a total of 80 dies. The two model types varied in die configuration (conical and root-formed), resin type, and post-processing techniques. Fabrication accuracy was evaluated after model delivery. The positional trueness was measured at baseline, after 10 and 50 repositioning cycles, by evaluating metric and angular die displacements. Deviations were compared between the groups using non-parametric Mann-Whitney-U tests at a significance level of 0.05.
Fabrication accuracy was similar for the two model sets. Trueness/precision were 72 ± 15 µm/76 ± 19 µm for center 1. For center 2, the corresponding values were 60 ± 5 µm/79 ± 4 µm. Significant differences in positional trueness were observed between the two model types after both 10 and 50 repositioning cycles. After 10 cycles, mean die displacements were 78 ± 76 µm for center 1 and 526 ± 470 µm for center 2 (p < 0.001). These values showed minimal variation after 50 cycles, with mean die displacements of 98 ± 80 µm for center 1 and 470 ± 386 µm for center 2 (p < 0.001). Angular deviations were minimal for both groups, even after 50 cycles, with deviations below 1°.
While the accuracy of the 3D-printed models was adequate, the positional trueness of the dies requires improvement, as some currently available models demonstrate unacceptable discrepancies.
The quality of 3D-printed models with removable dies for CAD/CAM crowns can vary substantially between milling centers. While some models can merely serve as restoration carriers, others are equipped with accurate dies that can be removed and repositioned reliably.
评估3D打印模型的准确性以及可摘代型的位置准确性。
为单冠制备一个牙科技工教学模型的切牙、尖牙、前磨牙和磨牙并进行数字化处理。基于此扫描结果，在两个加工中心3D打印两组模型（每组n = 10），共得到80个代型。两种模型类型在代型结构（锥形和根形）、树脂类型和后处理技术方面存在差异。模型交付后评估制作精度。通过评估代型的尺寸和角度位移，在基线、10次和50次重新定位循环后测量位置准确性。使用非参数曼-惠特尼-U检验在0.05的显著性水平下比较各组之间的偏差。
两组模型的制作精度相似。中心1的准确性/精密度为72±15 µm/76±19 µm。对于中心2，相应的值为60±5 µm/79±4 µm。在10次和50次重新定位循环后，两种模型类型之间均观察到位置准确性的显著差异。10次循环后，中心1的代型平均位移为78±76 µm，中心2为526±470 µm（p < 0.001）。50次循环后这些值变化最小，中心1的代型平均位移为98±80 µm，中心2为470±386 µm（p < 0.001）。两组的角度偏差均最小，即使在50次循环后，偏差低于1°。
虽然3D打印模型的准确性足够，但代型的位置准确性需要改进，因为一些现有模型存在不可接受的差异。
用于CAD/CAM冠的带可摘代型的3D打印模型的质量在不同加工中心之间可能有很大差异。虽然一些模型仅可作为修复体载体，但其他模型配备有可准确移除和可靠重新定位的代型。
