title: An in vitro evaluation of apicoectomies and retropreparations using different methods.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
authors.affiliation: Department of Restorative Dentistry, Araraquara School of Dentistry, São Paulo State University, Araraquara, Brazil.
authors.forename: Fábio Luiz
authors.initials: FL
authors.lastname: Camargo Villela Berbert
authors.forename: Norberto Batista
authors.initials: NB
authors.lastname: de Faria-Júnior
authors.forename: Mário
authors.initials: M
authors.lastname: Tanomaru-Filho
authors.forename: Juliane Maria
authors.initials: JM
authors.lastname: Guerreiro-Tanomaru
authors.forename: Idomeo
authors.initials: I
authors.lastname: Bonetti-Filho
authors.forename: Renato de Toledo
authors.initials: Rde T
authors.lastname: Leonardo
authors.forename: Rosemary Adriana Chierici
authors.initials: RA
authors.lastname: Marcantonio
mesh_terms: D000704:Analysis of Variance; D001047:Apicoectomy / Q000295:instrumentation / Q000379:methods; D003762:Dental Instruments; D018772:Dental Marginal Adaptation; D003804:Dentin / Q000033:anatomy & histology; D006171:Gutta-Percha; D006801:Humans; D053844:Lasers, Solid-State; D012184:Retrograde Obturation / Q000379:methods; D012387:Root Canal Filling Materials; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods; D018709:Statistics, Nonparametric; D014465:Ultrasonics
chemical_list: D012387:Root Canal Filling Materials; D006171:Gutta-Percha