title: Study of the progressive changes in canal shape after using different instruments by hand in simulated S-shaped canals.
abstract: 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).
authors: Key Laboratory of Oral Biomedical Engineering of the Ministry of Education, Department of Conservative Dentistry, West China Dental School, Sichuan University, Chengdu, China.
authors: Huang
authors: H
authors: Ding-ming
authors: Luo
authors: L
authors: Hong-xia
authors: Gary S-P
authors: GS
authors: Cheung
authors: Zhang
authors: Z
authors: Lan
authors: Tan
authors: T
authors: Hong
authors: Zhou
authors: Z
authors: Xue-dong
mesh_terms: D003722:Dental Alloys; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D009532:Nickel; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D013193:Stainless Steel; D014025:Titanium
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium