Shaping ability of ProFile and K3 rotary Ni-Ti instruments when used in a variable tip sequence in simulated curved root canals

Aim To compare the shaping ability of ProFile and K3 rotary Ni-Ti instruments when used in a variable tip sequence in simulated curved root canals with different curvature and radius. Methodology ProFile or K3 .06 taper instruments were used to prepare simulated canals of 20degrees curvature and 5 mm radius (n = 10) and 30degrees curvature and 3 mm radius canals (n = 10) in resin blocks. All canals were prepared to an apical size 40 at 0.5 mm from the canal terminus using a variable tip crown-down sequence. Pre- and postinstrumentation digital images were recorded, and an assessment of the canal shape was determined using a computer image analysis program. The material removal from the inner and outer wall of the canal was measured at 28 measuring points, beginning 0.5 mm from the end-point of the canal and the data compared using the Mann-Whitney U-test. Results In 20degrees and 30degrees canals both instruments significantly removed more (P < 0.05) material on the outer wall than the inner wall in the apical half of the canal. For ProFile files there was no significant difference in the amount of material removed on the outer canal wall between the 20degrees and 30degrees canals. However, in the K3 groups significantly more (P < 0.05) outer canal wall was removed in the apical area in 20degrees canals. When comparing both instruments the results showed that in 20degrees canals K3 instruments removed more outer and inner canal wall than ProFile instruments (P < 0.05) but that there was no significant difference (P > 0.05) between the instruments in 30degrees canals. Conclusion Within the limitation of this study, both rotary nickel-titanium instruments prepared a well-shaped root canal with minimal canal transportation.