title: A study on the survival of primary molars with intact and with defective restorations.
abstract: BACKGROUND
  Failed restorations in primary teeth are not always re-restored. Is re-restoration not required anymore?
  
  
  OBJECTIVE
  To compare survival rates of primary molars with intact and defective amalgam and ART restorations.
  
  
  METHODS
  A total of 649 restored primary molars, of which 162 were assessed with defective restorations for mechanical reasons, from a cluster-randomised controlled clinical trial, were followed up over a period of 3.5 years. Restored primary molars, extracted because of dental sepsis or toothache, were considered a failure. Primary molars with defective restorations were followed up from the time they were assessed defective. Data were analysed using PHREG model with frailty correction, Wald test, t-test, and jackknife procedure.
  
  
  RESULTS
  The survival rate of primary molars with intact restorations (96.3%) was statistically significantly higher than that of primary molars with defective restorations (75.9%) over a 3-year period (P < 0.0001). Neither the effect of treatment protocol (amalgam or ART) (P = 0.05) nor the type of surface (single or multiple) (P = 0.73) was observed with respect to the survival rate of restored primary molars.
  
  
  CONCLUSIONS
  Survival rates for primary molars with intact and defective amalgam and ART restorations were high. The 3-year survival rate of primary molars with intact restorations was significantly higher than that of primary molars with defective restorations.
authors.affiliation: Department of Dentistry, Faculty of Health Sciences, University of Brasília, Brasília, Brazil.
authors.forename: Leandro Augusto
authors.initials: LA
authors.lastname: Hilgert
authors.affiliation: Department of Oral Rehabilitation and Prosthetics, College of Dental Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Jo E
authors.initials: JE
authors.lastname: Frencken
authors.affiliation: Private Practice, Brasília, Brazil.
authors.forename: Rodrigo Guedes
authors.initials: RG
authors.lastname: de Amorim
authors.affiliation: Department of Oral Rehabilitation and Prosthetics, College of Dental Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: Mulder
authors.affiliation: Department of Dentistry, Faculty of Health Sciences, University of Brasília, Brasília, Brazil.
authors.forename: Soraya Coelho
authors.initials: SC
authors.lastname: Leal
mesh_terms: D001938:Brazil; D002648:Child; D003188:Composite Resins; D003723:Dental Amalgam / Q000627:therapeutic use; D057087:Dental Atraumatic Restorative Treatment; D003731:Dental Caries / Q000628:therapy; D003737:Dental Cavity Preparation / Q000145:classification / Q000379:methods / Q000592:standards; D003764:Dental Materials; D019232:Dental Restoration Failure / Q000706:statistics & numerical data*; D003793:Dental Restoration, Permanent / Q000379:methods / Q000592:standards; D005899:Glass Ionomer Cements / Q000627:therapeutic use; D006801:Humans; D008963:Molar / Q000000981:diagnostic imaging; D018805:Sepsis; D014094:Tooth, Deciduous / Q000000981:diagnostic imaging; D014098:Toothache; D016896:Treatment Outcome
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D005899:Glass Ionomer Cements; D003723:Dental Amalgam