title: Crack formation on resected root surfaces subjected to conventional, ultrasonic, and laser root-end cavity preparation.
abstract: OBJECTIVE
  The aim of this study was to evaluate cracks on root ends following resection and cavity preparation with a laser and two established techniques.
  
  
  BACKGROUND
  If root canal treatment of a tooth fails, an apicoectomy operation may be indicated. Three millimeters of the root tip is resected and a cavity of similar depth with parallel walls is cut to receive a root-end filling.
  
  
  METHODS
  Sixty extracted human maxillary anterior teeth were used. Their root canals were prepared with rotary instruments, and they were filled with gutta-percha. Twenty teeth were resected with tungsten carbide fissure burs, and their root-end cavities cut with tungsten carbide round burs at a slow speed (Group 1). The other 40 teeth were resected with an Er:YAG laser, and root-end cavities were made with the same laser (Group 2), or with an ultrasonically-powered zirconium nitride coated retrotip (Group 3). The number and types of cracks on the resected surfaces were assessed using a stereomicroscope before and after cavity preparation.
  
  
  RESULTS
  Cracking was not significantly different between the more conventional group and the laser groups after resections (p>0.05) or following cavity preparation (p>0.05).
  
  
  CONCLUSIONS
  In this in vitro study, the laser resection and root-end preparation technique did not influence the number or type of cracks formed on the root surfaces.
authors.affiliation: 1 Department of Endodontics, Faculty of Dentistry, Kocaeli University , Kocaeli, Turkey .
authors.forename: Seda
authors.initials: S
authors.lastname: Aydemir
authors.forename: Hale
authors.initials: H
authors.lastname: Cimilli
authors.forename: Gonca
authors.initials: G
authors.lastname: Mumcu
authors.forename: Nicholas
authors.initials: N
authors.lastname: Chandler
authors.forename: Nevin
authors.initials: N
authors.lastname: Kartal
mesh_terms: D001047:Apicoectomy; D003737:Dental Cavity Preparation / Q000379:methods*; D003786:Dental Pulp Cavity; D006801:Humans; D066298:In Vitro Techniques; D007834:Lasers; D014092:Tooth Root / Q000473:pathology*; D014464:Ultrasonic Therapy; D014465:Ultrasonics