An in vitro evaluation of apicoectomies and retropreparations using different methods

Objectives. The aim of this study was to evaluate: 1) the apical root surface, gutta-percha interface, and preparation time of root-end resections made with burs, ultrasound, or laser; and 2) the thickness of surrounding dentin after laser or ultrasonic root-end cavity preparation.Study design. 1) Thirty root-filled teeth were resected as follows: Zekrya bur in group I, Chemical Vapor Deposition (CVD) ultrasonic tip (9.5107-8) in group II, and ErCr:YSGG (Waterlase) in group III. The preparation time was recorded. Replicas of the resected root-ends were examined under a scanning electron microscope (SEM). 2) Thirty root-filled teeth were submitted to apicectomies and root-end cavities were prepared by using: CVD (6.1107-6) ultrasonic retrotips (group IV), EMS (DT-060) ultrasonic retrotips (group V), and ErCr: YSGG laser tips (group VI). Replicas of the root apices were examined under a SEM.Results. There were no fissures or fractures on root-end surfaces. The bur produced the smoothest surface (P < .05). Group I had the lowest preparation time (P < .05). The best adaptation between the filling and the root canals walls was observed in group III, but it was not significantly different from group II (P < .05). No resected root-ends had cracks after preparation. Group VI showed the least minimum dentin thickness (P < .05).Conclusions. The 3 methods evaluated did not cause any injury to the root-end surface, but they harmed the apical adaptation. Laser tips removed more dentin than ultrasonic retrotips and should be used with care to avoid overpreparation. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110:e57-e63)