Microcracks after apicoectomy with three surgical instruments: A comparative scanning electron microscopy study.

[BACKGROUND] Dentinal microcracks during apicoectomy may be influenced by the instrument used for root-end resection and preparation. Recognizing instrument-related crack formation is important for safer microsurgical choices.

[AIMS] To evaluate dentinal microcracks on root-end surfaces after resection with a tungsten carbide bur (TCB), a diamond-coated ultrasonic tip (DUT), and a surgical saw (SS), using scanning electron microscopy (SEM).

[MATERIALS AND METHODS] Sixty extracted single-rooted human canines were endodontically prepared and randomly allocated into three groups ( = 20) according to the instrument used. Resections were performed perpendicular to the long axis, removing 3 mm of the apex. Root-end surfaces were examined under SEM (×25) and microcracks classified into five subtypes.

[STATISTICAL ANALYSIS USED] Data were analyzed with SPSS 20.0 (SPSS Inc., Chicago, USA) using descriptive statistics and Chi-square tests. Odds ratios and logistic regression were applied to identify factors associated with the intervention. A significance level of α =0.05 and 95% confidence intervals were adopted.

[RESULTS] Instrument type influenced crack formation. The SS produced the highest proportion of complete cracks, whereas the DUT produced the lowest. Differences between groups were statistically supported.

[CONCLUSIONS] The DUT may minimize dentinal microcracks compared with the SS. Appropriate instrument selection and standardized technique can help reduce structural damage during apicoectomy.