de Moraes Aline Pinheiro, Poletto Neto Victório, Boscato Noéli, Pereira-Cenci Tatiana
Private practice, Rio Grande do Sul, Brazil.
Professor, Graduate Program in Dentistry, School of Dentistry, Federal University of Pelotas, Rio Grande do Sul, Brazil.
J Prosthet Dent. 2016 Jul;116(1):47-51. doi: 10.1016/j.prosdent.2015.11.022. Epub 2016 Feb 9.
Direct and indirect techniques are used for intracanal impression and fabrication of cast metal posts. However, whether those techniques affect the accuracy of cast metal posts is unknown.
The purpose of this randomized clinical trial was to evaluate the accuracy of cast metal posts depending on tooth position and impression technique.
Endodontically treated teeth (anterior or posterior) planned to receive cast metal posts and complete crowns were randomized according to impression technique (direct or indirect). Impressions were made by 2 operators, and time for the impression was recorded. All impressions and cast metal posts were photographed to assess any possible differences between techniques in length of the cast metal post.
All cast metal posts were shorter than the impressions. The mean reduction for the metal posts was 2.3% for direct in anterior teeth, 5.7% for direct in posterior teeth, 6.3% for indirect in anterior teeth, and 7.2% for indirect in posterior teeth (all P<.05). Statistically significant differences were found between time of technique and tooth position (P=.031), with the direct technique more time consuming than the indirect technique (P<.001) for both tooth positions. For the indirect technique, the impression times for both tooth groups were similar (P=.459).
Both of the intracanal impression techniques resulted in cast posts that were shorter than the impressed post space. The discrepancy was greatest for the indirect technique. Nevertheless, all posts were considered clinically acceptable and were cemented.
根管内印模和铸造金属桩的制作采用直接法和间接法。然而，这些技术是否会影响铸造金属桩的准确性尚不清楚。
本随机临床试验的目的是根据牙齿位置和印模技术评估铸造金属桩的准确性。
计划接受铸造金属桩和全冠修复的根管治疗牙齿（前牙或后牙）根据印模技术（直接法或间接法）进行随机分组。由两名操作人员制取印模，并记录印模时间。对所有印模和铸造金属桩进行拍照，以评估两种技术在铸造金属桩长度方面的任何可能差异。
所有铸造金属桩均比印模短。前牙直接法金属桩的平均缩短率为2.3%，后牙直接法为5.7%，前牙间接法为6.3%，后牙间接法为7.2%（均P<0.05）。技术时间和牙齿位置之间存在统计学显著差异（P=0.031），两种牙齿位置的直接法比间接法耗时更长（P<0.001）。对于间接法，两组牙齿的印模时间相似（P=0.459）。
两种根管内印模技术制作的铸造桩均比印模后的桩道空间短。间接法的差异最大。然而，所有桩在临床上均被认为可接受并进行了粘结。
