Comparison of the shaping ability of reciprocating instruments in simulated S-shaped canals / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the shaping ability of Reciproc, WaveOne,Mtwo and ProTaper instruments in simulated S-shaped root canals.</p><p><b>METHODS</b>A total of 40 simulated S-shaped resin blocks were divided randomly into four groups, each group was prepared with Reciproc (group A), WaveOne (group B), Mtwo (group C) and ProTaper (group D), respectively. The preparation time and reduction of working length after preparation were measured. Pre- and postoperative images were obtained by a scanner and superimposed using Photoshop. Changes of coronal curve and apical curve curvature, as well as material removal from the inner and outer canal wall at 10 points beginning 1 mm from the end point of the canal, were measured using ImageJ. Centering ability was determined, accordingly. The data were analyzed using the one-way ANOVA and Student-Newman-Keuls.</p><p><b>RESULTS</b>The preparation time of group A and group B were (42.1 ± 2.7) and (41.5 ± 3.2) s respectively, significantly less than that of group C and group D [(62.7 ± 2.8), (62.8 ± 5.2) s] (P < 0.05).Reductions of working length after preparation were not significantly different among the four groups (P > 0.05). Coronal curve curvature changes of group A, group B and group D were (4.69 ± 0.63)°, (4.15 ± 0.89)° and (4.13 ± 0.59)° respectively, significantly less than that of group C[(5.26 ± 0.70)°], P < 0.05. Apical curve curvature changes were not significantly different among the four groups (P > 0.05). At the 2 mm point, the centering ability of group A[ (-0.242 ± 0.042) mm], group B[(-0.191 ± 0.077) mm], and group D[(-0.272 ± 0.046) mm] was better than group C[(-0.343 ± 0.057 mm] significantly (P < 0.05). At the 3 mm and 4 mm point, the centering ability of group A and group B was better than group C and group D significantly (P < 0.05). Whilst at the 5 mm point, the centering ability of group D was better than group A and group B (P < 0.05).</p><p><b>CONCLUSIONS</b>Reciproc and WaveOne could complete preparation faster and could maintain the original S-shaped canal curvature better than Mtwo and ProTaper, especially in the apical part.</p>

Comparison of the shaping capability of reciprocating instruments in simulated canals in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aims to evaluate the shaping capability of Reciproc, WaveOne, Mtwo, and ProTaper instruments in simulated root canals.</p><p><b>METHODS</b>A total of 40 simulated resin blocks were divided randomly into four groups. Each group was prepared with Reciproc (Group 1), WaveOne (Group 2), Mtwo (Group 3), and ProTaper (Group 4). The preparation time and reduction in working length after preparation were measured. Pre- and post-operative images were obtained with a scanner and superimposed through Photoshop. The changes in canal curvature and material removal from the inner and outer canal walls at 10 points beginning at 1 mm from the end point of the canal were measured with Image J. Centering capability was determined accordingly. Data were analyzed through one-way ANOVA, SNK, and Kruskal-Wallis at a significance level of P < 0.05.</p><p><b>RESULTS</b>The preparation time of Group 2 was (53.7 ± 6.7) s, whereas those of Groups 1, 3, and 4 were (86.9 ± 8.1) s, (112.2 ± 8.2) s, and (177.9 ± 11.2) s, respectively; the difference was found to be significant (P < 0.05). The reductions in working length among the four groups after preparation were not significantly different (P > 0.05). The canal curvature for Groups 1 to 4 were 2.671° ± 0.637°, 2.667° ± 0.450°, 3.664° ± 0.870°, and 3.797° ± 0.601°, respectively. The changes for Groups 1 and 2 were significantly smaller than those for Groups 3 and 4. At the 3 mm point, the transportation of Group 1 was (-0.016 ± 0.094) mm, which was significantly less than that of the other instruments (P<0.05). At the 4 mm and 5 mm points, the trans- portation values of Group 2 were (-0.080 ± 0.104) mm and (-0.312 ± 0.088) mm, which were significantly less than that of Group 1 [(-0.243 ± 0.099) mm, (-0.404 ± 0.064) mm, P < 0.05].</p><p><b>CONCLUSION</b>Reciproc and WaveOne can complete preparation faster and can maintain the original canal curvature better than Mtwo and ProTaper. Reciproc exhibits superior centering capability in the apical part of the canal, whereas WaveOne exhibits superior centering capability in the middle part of the canal.</p>