Influence of operator expertise on glide path and root canal preparation of curved root canals with rotary and reciprocating motions

Abstract

This study intended to help practitioners selecting the appropriate motionaccording to their level of expertise for glide path and complete root canalpreparation of curved canals in terms of instrument fracture and preparationtime. A total of 160 curved root canals (angle>30°, radius<6 mm) were allo-cated randomly to 4 groups: A/B for expert operators and C/D for nonexpertoperators. A/C were shaped with rotary and B/D with reciprocating instru-ments. Preparation time was registered and compared with Kruskal–Wallisnon-parametric test and Dunn’s post hoc test. Instrument separation was alsoregistered and compared with chi-square test. A fractographic analysis was per-formed with scanning electron microscopy. The use of reciprocation motionsallowed nonexpert operators to avoid instrument breakage during glide pathand to prepare root canals faster. Experts were equally effective in rotary/re-ciprocating root canal shaping and faster with rotary motions than nonexpertoperators, who also fractured significantly more rotary instruments.