Saboury Abolfazl, Neshandar Asli Hamid, Dalili Kajan Zahra
Dept. of Prosthodontics, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Dental Sciences Research Center, Dept. of Prosthodontics, School of Dentistry, Guilan University of Medical Sciences, Rasht, Iran.
J Dent (Shiraz). 2017 Dec;18(4):289-297.
Precision of the impression taken from implant positions significantly determines accurate fit of implant-supported prostheses. An imprecise impression may produce prosthesis misfit.
This study aimed to evaluate the accuracy of four impression-making techniques for angulated implants by stereomicroscope through measuring the vertical marginal gaps between the cemented metal framework and the implant analog.
A definitive cast with two 15° mesially angulated implants served as the standard reference for making all the impressions and later for accuracy evaluation. Four groups of five samples were evaluated: (1) closed-tray snap-fit transfer, (2) open-tray nonsplinted impression coping, (3) metal splinted impression coping, and (4) fabricated acrylic resin transfer cap. A gold-palladium framework was fabricated over the angulated implant abutments, the fit of which was used as reference. The gaps between the metal framework and the implant analogs were measured in sample groups. Corresponding means for each technique and the definitive cast were compared by using ANOVA and post hoc tests.
The mean marginal gap was 38.16±0µm in definitive cast, 89±19.74µm in group 1, 78.66±20.63µm in group 2, 54.16±24.29µm in group 3, and 55.83±18.30µm in group 4. ANOVA revealed significant differences between the definitive cast and groups 1 and 2, but not with groups 3 and 4 (< 0.05).
Vertical gap measurements showed that metal splinted impression coping and fabricated acrylic resin transfer cap techniques produced quite more accurate impressions than closed-tray snap-fit transfer and open-tray nonsplinted impression coping techniques do. The fabricated acrylic resin transfer cap technique seems to be a reliable impression-making method.
从种植体位置获取的印模精度显著决定种植体支持修复体的精确贴合度。不精确的印模可能导致修复体不贴合。
本研究旨在通过立体显微镜测量粘结金属框架与种植体代型之间的垂直边缘间隙，评估四种用于成角种植体的印模制作技术的准确性。
带有两个向近中倾斜15°种植体的终模型作为制作所有印模及后续准确性评估的标准参考。对四组每组五个样本进行评估：（1）封闭式托盘卡扣式转移，（2）开放式托盘非夹板式印模帽，（3）金属夹板式印模帽，（4）定制丙烯酸树脂转移帽。在成角种植体基台上制作金钯框架，其贴合度用作参考。测量样本组中金属框架与种植体代型之间的间隙。使用方差分析和事后检验比较每种技术与终模型的相应均值。
终模型中的平均边缘间隙为38.16±0µm，第1组为89±19.74µm，第2组为78.66±20.63µm，第3组为54.16±24.29µm，第4组为55.83±18.30µm。方差分析显示终模型与第1组和第2组之间存在显著差异，但与第3组和第4组之间无显著差异（<0.05）。
垂直间隙测量表明，金属夹板式印模帽和定制丙烯酸树脂转移帽技术产生的印模比封闭式托盘卡扣式转移和开放式托盘非夹板式印模帽技术更精确。定制丙烯酸树脂转移帽技术似乎是一种可靠的印模制作方法。
