Ding-ming Huang, Hong-xia Luo, Cheung Gary S-P, Lan Zhang, Hong Tan, Xue-dong Zhou
Key Laboratory of Oral Biomedical Engineering of the Ministry of Education, Department of Conservative Dentistry, West China Dental School, Sichuan University, Chengdu, China.
J Endod. 2007 Aug;33(8):986-9. doi: 10.1016/j.joen.2006.12.008.
This study analyzed the progressive changes in canal shape after the use of different instruments by hand in simulated S-shaped canals. Forty simulated canals with double curvatures, 30 degrees coronally and 20 degrees apically, were randomly divided into four groups and prepared with stainless steel K-files, the ProTaper for hand use (PHU) system, NiTi K-files, and the combination of PHU and NiTi K-files, respectively, by hand. All canals were scanned pre-and postoperatively. Each postinstrumentation image was superimposed with the preoperative one in a computer. The amount of material removed after every instrument was measured at 14 points. Statistical analysis was performed using an analysis of variance (ANOVA) test at alpha=0.05. All four instruments straightened the S-shaped canals, except the combination of PHU (S1, Sx, and S2) and NiTi K-files, which created a continuous funnel shape. There was a significant difference in the amount of material removed between S2 and F1 of the PHU system (p<0.05), and the finishing files of PHU created the same transportation as the stainless steel instruments with the same tip size (p>0.05).
