Foraminal Deformation after Foraminal Enlargement with Rotary and Reciprocating Kinematics: A Scanning Electronic Microscopy Study.

INTRODUCTION

The aim of this study was to evaluate, under scanning electronic microscopy, the morphological aspect of apical foramen after root canal instrumentation with rotary and reciprocating kinematics at 2 different working length determinations.

METHODOLOGY

Sixty mesiobuccal roots of mandibular and maxillary molars presenting with curvature ranging from 30 to 65° were used in this study. The roots were initially scanned with a scanning electronic microscope under ×50 magnification. Roots were divided into 2 different groups (n = 30): group 1 instrumented with rotary kinematics, and group 2 instrumented with reciprocating kinematics. Both groups were instrumented at 2 different working lengths: at the apex and 1 mm beyond the apex. The roots were scanned after the instrumentation at the apex and again after further instrumentation 1 mm beyond the apex. The photomicrographs obtained were assigned to 3 independent evaluators for foraminal deformation assessment through comparison with baseline images. Evaluators were masked with regard to the kinematics and working length used. The Pearson correlation test and Kruskal-Wallis test (method of Dunn) were used for statistical analysis (P < .05).

RESULTS

The Pearson Correlation test showed good agreement among evaluators. Foraminal deformation was observed in instrumentation at the apex and 1 mm beyond the apex with both kinematics (P < .05).

CONCLUSIONS

Within the limitations of this study, it can be concluded that root canal instrumentation at the apex or 1 mm beyond the apex promoted deformation of the major foramen, regardless of the kinematics.