title: Efficacy of ultrasound in removal of intraradicular posts using different techniques.
abstract: The efficacy of ultrasound in removing cast metal posts was evaluated in this in vitro study using one or two ultrasound units and ultrasonic vibration for various lengths of time. The crowns of 30 healthy maxillary canines were removed, the roots were embedded in acrylic resin blocks, and the root canals were treated endodontically. The canals were prepared and their impressions were taken with self-curing acrylic resin. After casting with copper-aluminum alloy, the posts were blasted with aluminum oxide and cemented with Panavia F resin cement. The specimens were divided into five groups. In groups I and II, only one ultrasound unit was used for 30 and 60 s, respectively; in groups III and IV, two ultrasound units were used simultaneously for 30 and 60 s, respectively; in group V, ultrasound was not used (control). Ultrasonic vibrations were applied with an Enac OE-5 ultrasound unit and an ST-09 tip. All samples were subjected to traction on an Instron machine (model 4444) at a cross-head speed of 1 mm/min. Analysis of the results revealed a statistically significant difference between the groups (ANOVA, P < 0.01); however the difference between groups II and IV was not statistically significant. The efficacy of ultrasound in removing intraradicular posts was confirmed, and the most effective technique was the use of two ultrasound units, independent of the length of time ultrasound was applied.
authors.affiliation: School of Dentistry, University of Ribeirão Preto, UNAERP, Ribeirão Preto, SP, Brazil.
authors.forename: Neilor Mateus Antunes
authors.initials: NM
authors.lastname: Braga
authors.forename: Edson
authors.initials: E
authors.lastname: Alfredo
authors.forename: Luis Pascoal
authors.initials: LP
authors.lastname: Vansan
authors.forename: Tabajara Sabbag
authors.initials: TS
authors.lastname: Fonseca
authors.forename: José Antonio Brufato
authors.initials: JA
authors.lastname: Ferraz
authors.forename: Manoel Damião
authors.initials: MD
authors.lastname: Sousa-Neto
mesh_terms: D000535:Aluminum / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D003481:Cuspid; D003722:Dental Alloys / Q000737:chemistry; D003734:Dental Casting Investment / Q000737:chemistry; D020878:Device Removal; D006801:Humans; D011176:Post and Core Technique / Q000295:instrumentation*; D019279:Resin Cements / Q000737:chemistry; D012390:Root Canal Therapy; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D014465:Ultrasonics; D014732:Vibration
chemical_list: D003722:Dental Alloys; D003734:Dental Casting Investment; C438843:Panavia-Fluoro; D019279:Resin Cements; D003300:Copper; D000535:Aluminum