Detection of Dentinal Cracks after Root-end Resection: An Ex Vivo Study Comparing Microscopy and Endoscopy with Scanning Electron Microscopy

Abstract

Introduction Dentinal cracks are occasionally observed at the cut root face after root-end resection in apical surgery. The objective of this ex vivo study was to evaluate and compare the efficiency of visual aids to identify root-end dentinal cracks. Methods Twenty-six extracted human molars were decoronated, and the root canals were instrumented and filled. The apical 3 mm of the roots were resected, and the cut root faces were assessed with microscopy at ×16 and ×24 magnification and with endoscopy at ×8 and ×64 magnification (four visual aids). Roots were then duplicated for inspection with scanning electron microscopy. The presence, type, and location of cracks were registered by a blinded observer, with the scanning electron microcopy serving as the reference. The percentages of correct identification of dentinal cracks were then statistically compared among the four test configurations. Results Endoscopy ×64 showed the highest sensitivity for crack identification, irrespective of the applied methodology (ie, per root and per crack). However, higher scores of false-positive cracks (lower specificity) were found with endoscopy ×64 than with the other tested visual aids. The correct detection and location of complete canal cracks (55.3%, 52.6%, 68.4%, and 78.9%) were higher than the detection of incomplete canal cracks (42.2%, 42.2%, 52.0%, and 64.7%) using the four tested visual aids (microscopy at ×16 and ×24 magnification and endoscopy at ×8 and ×64 magnification, respectively). Only one of five intradentin cracks was identified with endoscopy ×64. Conclusions Overall, endoscopy ×64 proved the most accurate visual aid for the identification of dentinal cracks after root-end resection in extracted human teeth; however, it also provided the most false identifications.