Wee A G
College of Dentistry, The Ohio State University, Columbus, Ohio.
J Prosthet Dent. 2000 Mar;83(3):323-31. doi: 10.1016/s0022-3913(00)70136-3.
Given that meticulous implant prosthodontic procedures are recommended to obtain the best possible intraoral fit, impression materials that are suitable for use with a direct impression technique warrant further investigation.
This in vitro study compared the amount of torque required to rotate a square impression coping in an impression and evaluated the accuracy of solid implant casts fabricated from different impression materials.
Two direct transfer implant impressions were made using 8 impression materials; the torque required to rotate an impression coping in the impressions was calculated. Ten direct transfer implant impressions were made from the master model and poured in a die stone (Resin Rock) for 3 of the 8 initial impression material groups. Linear distances between steel balls placed on each abutment replica were measured with a traveling microscope to determine distortion in the impression procedure for each group. Data were analyzed (P =.05) with ANOVA and Ryan-Einot-Gabriel-Welsch multiple range test for post hoc.
With a 1-way ANOVA, average torque values among the material groups differed significantly (P =.001). Polyether (medium consistency) was found to produce the highest overall torque values, followed by addition silicone (high consistency), and then polysulfide (medium consistency). Statistically significant difference was also found among the 3 material groups' mean absolute cast error using a 1-way ANOVA (P =.0086). Implant casts made from polyether (medium) or addition silicone (high) impressions were significantly more accurate than casts made from polysulfide medium impressions.
On the basis of the results of this study, the use of either polyether (medium) or addition silicone (high) impression is recommended for direct implant impressions.
鉴于推荐采用精细的种植体修复程序以获得尽可能理想的口腔内贴合度，适用于直接印模技术的印模材料值得进一步研究。
本体外研究比较了在印模中旋转方形印模帽所需的扭矩量，并评估了由不同印模材料制作的实体种植体模型的准确性。
使用8种印模材料制作两个直接转移种植体印模；计算在印模中旋转印模帽所需的扭矩。从主模型制作10个直接转移种植体印模，并为8个初始印模材料组中的3组灌注石膏模型（树脂岩）。用移动显微镜测量放置在每个基台复制体上的钢球之间的线性距离，以确定每组在印模过程中的变形情况。数据采用方差分析（P = 0.05）和Ryan-Einot-Gabriel-Welsch多重范围检验进行事后分析。
采用单因素方差分析，材料组之间的平均扭矩值存在显著差异（P = 0.001）。发现聚醚（中等稠度）产生的总体扭矩值最高，其次是加成型硅橡胶（高稠度），然后是聚硫橡胶（中等稠度）。使用单因素方差分析还发现，3种材料组的平均绝对模型误差之间存在统计学显著差异（P = 0.0086）。由聚醚（中等稠度）或加成型硅橡胶（高稠度）印模制作的种植体模型比由聚硫橡胶中等稠度印模制作的模型显著更精确。
根据本研究结果，推荐使用聚醚（中等稠度）或加成型硅橡胶（高稠度）印模进行直接种植体印模。
