Department of Prosthodontics, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, Seoul, Korea.
J Prosthet Dent. 2011 Jun;105(6):367-73. doi: 10.1016/S0022-3913(11)60075-9.
Implant impressions without impression copings can be used for cement-retained implant restorations. A comparison of the accuracy of implant impressions with and without impression copings is needed.
The purpose of this study was to evaluate and compare the dimensional accuracy of implant definitive casts that are fabricated by implant impressions with and without impression copings.
An acrylic resin maxillary model was fabricated, and 3 implant replicas were secured in the right second premolar, first, and second molars. Two impression techniques were used to fabricate definitive casts (n=10). For the coping group (Group C), open tray impression copings were used for the final impressions. For the no-coping group (Group NC), cementable abutments were connected to the implant replicas, and final impressions were made assuming the abutments were prepared teeth. Computerized calculation of the centroids and long axes of the implant or stone abutment replicas was performed. The Mann-Whitney U test analyzed the amount of linear and rotational distortion between groups (α =.05).
At the first molar site, Group NC showed significantly greater linear distortion along the Y-axis, with a small difference between the groups (Group C, 7.8 ± 7.4 μm; Group NC, 19.5 ± 12.2). At the second molar site, increased distortion was noted in Group NC for every linear and rotational variable, except for linear distortion along the Z-axis.
Implant impression with open tray impression copings produced more accurate definitive casts than those fabricated without impression copings, especially those with greater inter-abutment distance.
无印模帽的种植体印模可用于粘结固位种植体修复。需要比较有和无印模帽的种植体印模的准确性。
本研究的目的是评估和比较使用有和无印模帽的种植体印模制取的种植体最终模型的尺寸精度。
制作丙烯酸树脂上颌模型，将 3 个种植体模型固定在右侧第二前磨牙、第一和第二磨牙。使用两种印模技术制作最终模型（n=10）。对于带帽组（C 组），使用开放式托盘印模帽进行最终印模。对于无帽组（NC 组），将可粘结基台连接到种植体模型上，并假设基台为预备牙进行最终印模。对种植体或石质基台模型的质心和长轴进行计算机计算。采用曼-惠特尼 U 检验分析组间的线性和旋转偏差量（α=.05）。
在第一磨牙部位，NC 组沿 Y 轴的线性变形显著更大，两组之间差异较小（C 组为 7.8±7.4μm；NC 组为 19.5±12.2μm）。在第二磨牙部位，NC 组在每个线性和旋转变量中都出现了更大的变形，除了 Z 轴的线性变形。
与无印模帽相比，开放式托盘印模帽制取的种植体印模可产生更精确的最终模型，特别是在基台间距较大时。
