Department of Prosthodontics, School of Dentistry, University of Sao Paulo, Sao Paulo, Brazil.
Int J Oral Maxillofac Implants. 2010 Nov-Dec;25(6):1115-24.
The aim of this study was to evaluate, using scanning electron microscopy (SEM), the accuracy of four impression techniques for osseointegrated implants (with or without acrylic resin splinting and with irreversible hydrocolloid or polyvinyl siloxane [PVS] impression material).
A metal master model was made with three implant analogs and two prosthetic spaces. This model was used as the standard for all impressions. Two impression materials were used (irreversible hydrocolloid and PVS) and two transfer techniques were used (squared impression copings indexed by the impression material and squared impression copings splinted with acrylic resin). Four groups were therefore analyzed (n = 5): IH = irreversible hydrocolloid only, IHS = irreversible hydrocolloid + splint, P = PVS only, and PS = PVS + splint. A reference framework made with palladium-silver alloy over the UCLA abutment was created on the master model. The fit of this structure to the master model was used as a reference. SEM images of the front and side gaps between the abutments and the implant analogs were created and then measured using image analysis software.
IH presented the largest misfit. The splinted impression copings generated a smaller marginal gap than the indexed material technique, irrespective of the impression material used. There was no significant difference between IHS, P, PS, and the reference (multivariate test, Wilks criteria). However, PS presented a standard deviation that was three times lower than those of the other groups, and its mean was closer to the reference.
The IH impression technique was the least accurate technique. There was no difference between IHS, P, and PS techniques with regard to the reference constant. The impression techniques that used splinted impression copings generated more accurate casts, irrespective of the impression material.
本研究旨在通过扫描电子显微镜（SEM）评估四种骨整合种植体印模技术（带或不带丙烯酸树脂夹板以及使用不可逆水胶体或聚硅氧烷[PVS]印模材料）的准确性。
使用三个种植体模拟体和两个修复空间制作金属主模型。该模型被用作所有印模的标准。使用了两种印模材料（不可逆水胶体和 PVS）和两种转移技术（用印模材料标记的方形印模套和用丙烯酸树脂夹板的方形印模套）。因此，分析了四个组（n=5）：IH = 仅不可逆水胶体，IHS = 不可逆水胶体+夹板，P = 仅 PVS，和 PS = PVS+夹板。在主模型上创建了一个用钯银合金制成的参考框架，位于 UCLA 基台上方。该结构与主模型的拟合用作参考。创建了种植体模拟体和基台之间的前侧和侧面间隙的 SEM 图像，然后使用图像分析软件进行测量。
IH 呈现最大的不匹配。无论使用何种印模材料，夹板印模套产生的边缘间隙都小于标记材料技术。IHS、P、PS 和参考组（多变量检验，Wilks 标准）之间没有显著差异。然而，PS 的标准偏差低了三倍，其平均值更接近参考值。
IH 印模技术是最不准确的技术。IHS、P 和 PS 技术与参考常数之间没有差异。使用夹板印模套的印模技术产生了更准确的印模，无论印模材料如何。
