title: Time required to remove totally bonded tooth-colored posterior restorations and related tooth substance loss.
abstract: OBJECTIVE
  The study was conducted to measure the time required to remove large totally bonded tooth-colored posterior restorations and related tooth substance loss. This information was collected to determine if there were differences between bonded restorations and conventional restorations.
  
  
  METHODS
  Molars were restored with the following materials: amalgam, composite, glass ionomer cement or glass ceramic cusp coverages. After submitting them to an in vitro aging process, they were attached to a lower jaw model in a phantom head. Six dentists removed the test restorations under standardized, quasi-clinical conditions.
  
  
  RESULTS
  While the amalgam was completely removed, some glass ionomer cement vestiges were found. In the glass-ceramic group, the margins were covered with remnants of the composite luting agent in several places. The most restorative material was left in the composite group. The loss of tooth structure after removal of amalgam, glass ionomer cement, composite and glass ceramic was 17.6 mm3, 19.6 mm3, 39.9 mm3 and 41.8 mm3, respectively. When comparing the removal time, the glass ionomer group scored best with an average of 11.9 min followed by the amalgam group with an average of 15.2 min, followed by 24.9 min for the composite group and 30.4 min for the glass ceramic group.
  
  
  CONCLUSIONS
  The removal of totally bonded posterior restorations made of composite and ceramic is more technically demanding and more time-consuming than the removal of glass ionomer and amalgam restorations.
mesh_terms: D000180:Acrylic Resins; D000704:Analysis of Variance; D001641:Bicuspid / Q000473:pathology; D002516:Ceramics; D003188:Composite Resins; D003722:Dental Alloys; D003723:Dental Amalgam; D017005:Dental Debonding; D003743:Dental Enamel / Q000473:pathology; D003793:Dental Restoration, Permanent; D017220:Dentin-Bonding Agents; D005069:Evaluation Studies as Topic; D005899:Glass Ionomer Cements; D006801:Humans; D007284:Inlays; D008298:Maleates; D008963:Molar / Q000473:pathology; D011140:Polyurethanes; D018709:Statistics, Nonparametric; D013997:Time Factors
chemical_list: D000180:Acrylic Resins; D003188:Composite Resins; D003722:Dental Alloys; D017220:Dentin-Bonding Agents; D005899:Glass Ionomer Cements; D008298:Maleates; D011140:Polyurethanes; C062652:Prisma Universal Bond; C059495:dicor cement; C069353:Brilliant Dentin resin; C074543:Cerec; D003723:Dental Amalgam; C040964:Ketac-Fil; C072894:Valiant PhD