title: Long-term survival of extensive amalgams and posterior crowns.
abstract: OBJECTIVE
  There is very little information available from private dental practices on the comparative survivals of extensive posterior amalgam restorations and posterior crowns placed in the same patient population. Therefore, the present retrospective study examined the performance of such restorations at three long-established Adelaide city practices.
  
  
  METHODS
  Life-table survival estimates were generated for 160 extensive amalgams, 96 cast gold crowns and 174 ceramometal crowns. The restorations were placed by 20 dentists at various times in 100 patients who attended the practices on a regular basis for around 25 years on average.
  
  
  RESULTS
  There were no significant differences found in the survival times for both types of crowns, with around 70% still being present at 20 years. However, the median survival time for the extensive amalgams was much lower, at 14.6 years. Despite these differences in survival times, the extensive amalgam restorations survived for longer than is usually expected.
  
  
  CONCLUSIONS
  In this present study, the survival findings have implications for the most cost-effective dental treatments of large lesions in posterior teeth.
authors.affiliation: University of Hong Kong, Department of Conservative Dentistry, Prince Philip Dental Hospital, Hong Kong.
authors.forename: R J
authors.initials: RJ
authors.lastname: Smales
authors.forename: W S
authors.initials: WS
authors.lastname: Hawthorne
mesh_terms: D001641:Bicuspid; D003362:Cost-Benefit Analysis; D003442:Crowns / Q000191:economics / Q000706:statistics & numerical data; D003723:Dental Amalgam / Q000191:economics; D003793:Dental Restoration, Permanent / Q000191:economics / Q000706:statistics & numerical data; D006047:Gold Alloys; D006801:Humans; D015993:Life Tables; D016876:Metal Ceramic Alloys; D008963:Molar; D012189:Retrospective Studies; D013021:South Australia / Q000453:epidemiology; D013997:Time Factors
chemical_list: D006047:Gold Alloys; D016876:Metal Ceramic Alloys; D003723:Dental Amalgam