Vigolo P, Majzoub Z, Cordioli G
University of Padova, Padova, Italy.
J Prosthet Dent. 2000 May;83(5):562-6. doi: 10.1016/s0022-3913(00)70015-1.
The inaccuracy in transferring the position of the hexagonal head of a single implant to the working cast can result in a final single tooth crown, which clinically may present occlusal and/or interproximal contacts that are different from those contacts on the master cast obtained by the technician.
This in vitro study evaluated the accuracy of the master casts obtained using square pick-up impression copings for single-tooth replacement. Copings used were (1) copings as sold by the manufacturer, and (2) copings modified by sandblasting and coating with impression adhesive their roughened surfaces before final impression procedures.
A polymeric resin model with a standard single implant was used to simulate a clinical situation. A group of 20 impressions were made using nonmodified impression copings; a second group of 20 impressions were fabricated with modified copings. Master casts fabricated for both groups were analyzed to detect rotational position change of the hexagon on the implant replicas in the master casts in reference to the resin model.
The rotational position changes of the hexagon on implant replicas were significantly less variable in the master casts obtained with the modified impression copings than in the master casts achieved with the nonprepared copings.
Improved precision of the impression was achieved when the adhesive-coated copings were used.
将单个种植体六角形头部的位置转移到工作模型时的不准确性，可能会导致最终的单颗牙冠在临床上出现与技术人员制作的主模型上的接触不同的咬合和/或邻面接触。
本体外研究评估了使用方形取模印模帽进行单颗牙替换时获得的主模型的准确性。使用的印模帽为：（1）制造商销售的印模帽，以及（2）在最终印模程序前对其粗糙表面进行喷砂处理并涂覆印模粘合剂的改良印模帽。
使用带有标准单颗种植体的聚合树脂模型模拟临床情况。一组20个印模使用未改良的印模帽制作；另一组20个印模使用改良后的印模帽制作。对两组制作的主模型进行分析，以检测主模型中种植体复制件上六边形相对于树脂模型的旋转位置变化。
与使用未处理印模帽获得的主模型相比，使用改良印模帽获得的主模型中种植体复制件上六边形的旋转位置变化明显更小。
使用涂有粘合剂的印模帽时，印模的精度得到了提高。
