title: Effect of the simulated periodontal ligament on cast post-and-core removal using an ultrasonic device.
abstract: OBJECTIVE
  The aim of this study was to evaluate the effect of simulated periodontal ligament (SPDL) on custom cast dowel and core removal by ultrasonic vibration.
  
  
  METHODS
  Thirty-two human maxillary canines were included in resin cylinders with or without SPDL made from polyether impression material. In order to allow tensile testing, the roots included in resin cylinders with SPDL were fixed to cylinders with two stainless steel wires. Post-holes were prepared by standardizing the length at 8 mm and root canal impressions were made with self-cured resin acrylic. Cast dowel and core sets were fabricated and luted with Panavia F resin cement. Half of the samples were submitted to ultrasonic vibration before the tensile test. Data were analyzed statistically by two-way ANOVA and Tukey's post-hoc tests (p<0.05).
  
  
  RESULTS
  The ultrasonic vibration reduced the tensile strength of the samples directly included in resin cylinders. There was no difference between the values, whether or not ultrasonic vibration was used, when the PDL was simulated. However, the presence of SPDL affected the tensile strength values even when no ultrasonic vibration was applied.
  
  
  CONCLUSIONS
  Simulation of PDL has an effect on both ultrasonic vibration and tensile testing.
authors.affiliation: Department of Dentistry, Dental School, State University of Montes Claros, Montes Claros, MG, Brazil. andrelfsilva@hotmail.com
authors.forename: Manoel
authors.initials: M
authors.lastname: Brito-Junior
authors.forename: Neilor Mateus Antunes
authors.initials: NM
authors.lastname: Braga
authors.forename: Danilo Costa
authors.initials: DC
authors.lastname: Rodrigues
authors.forename: Carla Cristina
authors.initials: CC
authors.lastname: Camilo
authors.forename: André Luis
authors.initials: AL
authors.lastname: Faria-e-Silva
mesh_terms: D000704:Analysis of Variance; D003481:Cuspid; D003762:Dental Instruments; D020878:Device Removal / Q000295:instrumentation*; D006801:Humans; D008422:Materials Testing; D010513:Periodontal Ligament; D011176:Post and Core Technique / Q000295:instrumentation*; D019279:Resin Cements; D018915:Root Canal Preparation; D013718:Tensile Strength; D014465:Ultrasonics; D014732:Vibration
chemical_list: D019279:Resin Cements