title: The influence of ultrasound on the retention of cast posts cemented with different agents.
abstract: OBJECTIVE
  The aim of this study was to evaluate the influence of ultrasound during the removal of posts cemented with either zinc phosphate cement, glass ionomer cement or resin cement.
  
  
  METHODS
  Eighty-four single-rooted teeth were prepared and after cementation of cast posts, they were randomly divided into six groups of 14. Group 1, 2 and 3 did not receive ultrasonic vibration, whilst groups 4, 5 and 6 received ultrasonic vibration for 10 min. The force necessary for post removal was determined using a universal testing machine. Results were statistically analysed using ANOVA and Tukey tests (5%).
  
  
  RESULTS
  The application of ultrasonic vibration reduced the retention provided by zinc phosphate and glass ionomer cements by 39% and 33%, respectively.
  
  
  CONCLUSIONS
  A statistically significant reduction in the force necessary to remove posts cemented with zinc phosphate and glass ionomer cements occurred following application of ultrasound. The application of ultrasonic vibration did not influence the retention of cast posts cemented with resin cement.
authors: Department of Endodontics, São José dos Campos School of Dentistry, UNESP Avenida Francisco José Longo, 777, São Dimas, CEP 12.201-970, São José dos Campos, São Paulo, Brazil. galera@netdata.com.br
authors: A P
authors: AP
authors: Gomes
authors: C H
authors: CH
authors: Kubo
authors: R A
authors: RA
authors: Santos
authors: D R
authors: DR
authors: Santos
authors: R Q
authors: RQ
authors: Padilha
mesh_terms: D000704:Analysis of Variance; D002484:Cementation; D003722:Dental Alloys; D003734:Dental Casting Investment; D003738:Dental Cements / Q000737:chemistry; D017005:Dental Debonding; D017268:Dental Prosthesis Retention; D003799:Dental Stress Analysis / Q000295:instrumentation; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D011176:Post and Core Technique; D019279:Resin Cements / Q000737:chemistry; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D014465:Ultrasonics; D014732:Vibration; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: D003722:Dental Alloys; D003734:Dental Casting Investment; D003738:Dental Cements; D005899:Glass Ionomer Cements; D019279:Resin Cements; D015036:Zinc Phosphate Cement