Effects of ultrasonic root end preparation on resected root surfaces : SEM evaluation

Objective: The purpose of this study was to investigate the in vitro effect of ultrasonic retrotips on root end surfaces. Study design: Root end resection was performed on 45 single-root teeth endodontically treated after extraction. Setting the ultrasonic device at full power, a retrograde cavity was made by a stainless steel tip in 9 specimens (SS-FP). In another 9 samples a diamond tip was used (D-FP). Setting the intensity of the ultrasonic device at half power, 9 specimens were treated using stainless steel tips (SS-HP) and 9 using diamond tip (D-HP). Nine teeth were only apically resected and used as controls. Histologic serial sections were examined by scanning electron microsope to assess the number of root-face cracking, the marginal quality, and the crack type. Results: No significant difference between diamond and stainless steel groups was found at a given power setting. Significant differences were found between SS-FPand SS-HP group for both the number of cracks and the marginal quality.