title: Comparison of two methods for the removal of root canal posts.
abstract: OBJECTIVE
  To compare the application of ultrasound with the use of an engine-driven trephine bur to remove parallel-sided root canal posts.
  
  
  METHODS
  Single-rooted human canine teeth were decoronated and prepared to receive preformed titanium posts. The posts were cemented with Panavia F resin cement. Ten teeth acted as controls, 10 had a 4-mm-deep gutter cut around the post using a Masserann trephining bur, and 10 were subjected to 10 minutes of ultrasound. The forces required to dislodge the posts were determined using a universal testing machine, and the data were analyzed using analysis of variance.
  
  
  RESULTS
  The only significant difference was between the trephined and ultrasonically energized groups, with the ultrasonic group requiring greater forces for dislodgement.
  
  
  CONCLUSIONS
  Resin composite cement could be removed from around the posts with the trephine bur but with considerable difficulty, and neither method of dislodging the posts was effective.
authors.affiliation: Department of Oral Rehabilitation, School of Dentistry, University of Otago, Dunedin, New Zealand. nick.chandler@stonebow.otago.ac.nz
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Chandler
authors.forename: Alison J E
authors.initials: AJ
authors.lastname: Qualtrough
authors.forename: David G
authors.initials: DG
authors.lastname: Purton
mesh_terms: D000704:Analysis of Variance; D002484:Cementation; D003481:Cuspid; D017005:Dental Debonding / Q000379:methods*; D006801:Humans; D011176:Post and Core Technique / Q000295:instrumentation*; D019279:Resin Cements / Q000737:chemistry; D018915:Root Canal Preparation / Q000295:instrumentation; D013314:Stress, Mechanical; D013718:Tensile Strength; D014025:Titanium; D014465:Ultrasonics
chemical_list: C438843:Panavia-Fluoro; D019279:Resin Cements; D014025:Titanium