Espir, C. G. [UNESP]Nascimento-Mendes, C. A. [UNESP]Guerreiro-Tanomaru, J. M. [UNESP]Freire, L. G.Gavini, G.Tanomaru-Filho, M. [UNESP]2018-11-262018-11-262018-05-01International Endodontic Journal. Hoboken: Wiley, v. 51, n. 5, p. 541-548, 2018.0143-2885http://hdl.handle.net/11449/164086AimTo evaluate oval root canal preparation using one or two instruments in counterclockwise or clockwise reciprocating motion. MethodologyThe radiographic diameter of mandibular human incisors was evaluated, and oval canals were selected (2Diameter Ratio4). Fifty-seven teeth were assigned to root canal preparation (n=19): Reciproc 40 (R40) in a counterclockwise reciprocating motion; Mtwo size 40, .06 taper (M 40.06) in a clockwise reciprocating motion or Mtwo size 20, .06 taper and size 40, .06 taper (M 20/40.06) in a clockwise reciprocating motion. Mtwo instruments were coupled to an ENDO DUAL motor, turning 150 degrees clockwise and 30 degrees counterclockwise. Scanning was performed before and after root canal preparation using a SkyScan 1176 micro-computed tomography. Volume, percentage of debris and percentage of uninstrumented surface were analysed in the entire root canal and in each third of the canal. Data were compared using anova and Tukey's tests or Kruskal-Wallis and Dunn tests. ResultsThe Reciproc and Mtwo systems using different kinematics were associated with a similar increase in root canal volume. Additionally, both system had similar percentage of uninstrumented surface (P>0.05). Mtwo size 20, .06 taper and size 40, .06 taper was associated with significantly lower debris (P<0.05) in the middle third (0.56%) when compared to R40 (1.31%) and M size 40, .06 taper (1.54%). ConclusionsThe conventional reciprocation motion for R40 and the clockwise reciprocation motion for Mtwo resulted in similar root canal preparations. Less remaining debris was present in the middle third when two instruments with different diameters were used.541-548engmicro-computed tomographyreciprocating motionroot canal preparationArtigo10.1111/iej.12776WOS:000429544400006Acesso restrito