Grazziotin-Soares Renata, Barato Filho Flares, Vanni José Roberto, Almeida Susimara, Oliveira Elias Pandonor Motcy de, Barletta Fernando Branco, Limongi Orlando
Department of Restorative Dentistry, Dental School, ULBRA - Lutheran University of Brazil, Canoas, RS, Brazil.
Braz Dent J. 2011;22(3):218-22. doi: 10.1590/s0103-64402011000300007.
This study used a mechanical test to evaluate the flexibility of instruments from the K3 (conicity 0.04) and the ProTaper Universal systems when they were new and after 5 uses in simulated canals. Five sets of instruments of each system were tested: K3 (15, 20, 25, 30, 35, 40 and 45) and ProTaper Universal (S1, S2, F1, F2, F3, F4 and F5). Each set of instruments was used to prepare a simulated canal and the same set of instruments was used 5 times (50 canals). The number of each subgroup represented the number of uses: 0 (control), 1, 3 and 5 uses. Before and after each use, the instruments were submitted to a mechanical flexibility test performed in a Versat 502 universal testing machine. Interactions between the instrument and the number of uses were analyzed by ANOVA and Tukey's test at a 5% level of significance. Instruments from both systems presented lower flexibility after the third use compared to the flexibility obtained after uses 0 and 1 (p<0.05), and maintained the same flexibility after the fifth use. The flexibility of instruments from the K3 system decreased with the increase of diameter, irrespective of the number of uses. Among the instruments from the ProTaper Universal system, the shaping files presented greater flexibility than the finishing files. F2 and F3 were the least flexible instruments, and F4 and F5 presented flexibility values similar to those of F1.
本研究采用机械测试来评估K3系统（锥度0.04）和ProTaper通用系统的器械在新器械状态下以及在模拟根管中使用5次后的柔韧性。对每个系统的五套器械进行了测试：K3系统（15、20、25、30、35、40和45号）和ProTaper通用系统（S1、S2、F1、F2、F3、F4和F5号）。每组器械用于预备一条模拟根管，同一组器械使用5次（共预备50条根管）。每个亚组的数量代表使用次数：0次（对照）、1次、3次和5次。每次使用前后，将器械在Versat 502通用试验机上进行机械柔韧性测试。采用方差分析和Tukey检验在5%显著性水平下分析器械与使用次数之间的相互作用。与使用0次和1次后获得的柔韧性相比，两个系统的器械在使用3次后柔韧性均降低（p<0.05），且在使用5次后保持相同的柔韧性。K3系统器械的柔韧性随直径增加而降低，与使用次数无关。在ProTaper通用系统的器械中，成形锉比精修锉具有更大的柔韧性。F2和F3是柔韧性最差的器械，F4和F5的柔韧性值与F1相似。
