title: Replacement risk of amalgam treatment modalities: 15-year results.
abstract: OBJECTIVE
  This paper reports on the replacement risk of different treatment modalities for Class II amalgam restorations in a clinical trial of 15 years duration.
  
  
  METHODS
  The performance of 1117 conventional Class II amalgam restorations in a controlled, longitudinal study were analysed using logistic regression with a random component. Primary variables regarding replacement risk were the treatment modality (cavity wall treatments) and alloy (conventional versus high copper). Secondly, the operator, type of tooth and type of restoration (MO/DO vs MOD) were considered.
  
  
  RESULTS
  Over 15 years, 17% of the restorations were replaced (true failures). The application of copalite varnish or silver suspension and the type of alloy did not reduce the replacement risk. Reduced risks were observed by providing a 90-degree cavosurface angle combined with a cavity wall finish. The operator and the type of restoration determine replacement risk to a significant extent.
  
  
  CONCLUSIONS
  Additional treatment modalities do not necessarily reduce replacement risks of Class II amalgam restorations within 15 years, while clinical variables affect the risk of replacement to a certain degree.
authors.affiliation: Division Cariology, Endodontology and Pedodontology, Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands. c.kreulen@acta.nl
authors.forename: C M
authors.initials: CM
authors.lastname: Kreulen
authors.forename: H
authors.initials: H
authors.lastname: Tobi
authors.forename: R J
authors.initials: RJ
authors.lastname: Gruythuysen
authors.forename: W E
authors.initials: WE
authors.lastname: van Amerongen
authors.forename: P J
authors.initials: PJ
authors.lastname: Borgmeijer
mesh_terms: D000328:Adult; D003723:Dental Amalgam / Q000737:chemistry; D003736:Dental Cavity Lining; D003737:Dental Cavity Preparation; D003764:Dental Materials; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000379:methods*; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D016017:Odds Ratio; D012116:Resins, Plant; D012307:Risk Factors
chemical_list: D003764:Dental Materials; D012116:Resins, Plant; C023806:Copalite; D003723:Dental Amalgam