title: Efficacy of two methods for restorative materials' removal in primary teeth.
abstract: OBJECTIVE
  This in vitro study aimed to compare the time required for removal, the presence of residues of restorative material, tooth structure loss and dental surface morphology after removal of composite resin and amalgam restorations from occlusal cavities in primary molars using conventional high-speed bur and CVDentus® ultrasonic diamond tips.
  
  
  METHODS
  A total of 37 primary molars were allocated into four groups: Group 1 (n=9)-amalgam restorations removed using high-speed bur; Group 2 (n=10)-amalgam restorations removed using ultrasonic tip; Group 3 (n=8)- composite resin restorations removed using high-speed bur; Group 4 (n=10)-composite resin restorations removed using ultrasonic tip. After being restored, teeth were sectioned and analyzed through stereoscopic microscope images before and after restoration removal. The structural loss was analyzed by software of image analysis, and an examiner assessed for the presence of residues. Scanning electron microscopy was used to evaluate the morphology. Time and structural loss values were compared using ANOVA, and the percentages of samples with residues using Fisher test.
  
  
  RESULTS
  There was no statistically significant difference in the tooth structure loss among different methods and restorative materials, as well as in the presence of residues of restorative material. However, diamond burs were faster than the ultrasonic method for both materials. Differences in dental morphology were observed between the methods of restoration removal, but not related to the restorative material.
  
  
  CONCLUSIONS
  Both conventional high-speed bur and ultrasonic diamond tip methods remove similar amounts of tooth structure, but the removal performed with diamond tips in ultrasonic devices is slower.
  
  
  CONCLUSIONS
  This study shows that both ultrasonic and conventional high-speed bur methods for removing restorations generate similar loss of sound dental tissue, but the former is slower.
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry of University of São Paulo, Brazil.
authors.forename: Daniela Gonçalves
authors.initials: DG
authors.lastname: Bittar
authors.forename: Christiana
authors.initials: C
authors.lastname: Murakami
authors.forename: Daniela
authors.initials: D
authors.lastname: Hesse
authors.forename: José Carlos Pettorossi
authors.initials: JC
authors.lastname: Imparato
authors.forename: Fausto Medeiros
authors.initials: FM
authors.lastname: Mendes
mesh_terms: D003188:Composite Resins / Q000737:chemistry; D003723:Dental Amalgam / Q000737:chemistry; D003737:Dental Cavity Preparation / Q000295:instrumentation; D003754:Dental High-Speed Equipment; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure; D018130:Diamond / Q000737:chemistry; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000648:ultrastructure; D016369:Smear Layer; D013997:Time Factors; D014094:Tooth, Deciduous / Q000648:ultrastructure*; D014465:Ultrasonics / Q000295:instrumentation
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C444701:Filtek Z250; D018130:Diamond; D003723:Dental Amalgam