title: Prevalence of cusp fractures in teeth restored with amalgam and with resin-based composite.
abstract: BACKGROUND
  Complete cusp fracture in restored teeth is a common problem observed in general dental practice. Many dentists believe that teeth restored with amalgam are more likely to be associated with cusp fractures than are those restored with resin-based composite. METHODS. The authors noted the condition of 10,869 posterior teeth with amalgam or resin-based composite restorations with at least one cusp present, unrestored or missing in 1,902 consecutively seen adult patients in a private general dental practice. For each patient, the authors recorded age, type of restorations, number of surfaces of each restoration, and presence or absence of a complete cusp fracture and of caries.
  
  
  RESULTS
  There was a lower percentage of cusp fractures in younger subjects than in older subjects and in teeth with a single restored surface than in those with more than one restored surface. There was no significant difference in the prevalence of cusp fracture rates in amalgam-restored teeth versus composite-restored teeth in subjects aged 18 through 54 years. In subjects aged 55 through 96 years, there was a marginally significantly greater cusp fracture rate in composite-restored teeth than in those restored with amalgam. Overall, there was no significant difference in the prevalence of cusp fracture in teeth restored with amalgam (1.88 percent) versus composite-restored teeth (2.29 percent).
  
  
  CONCLUSIONS
  The prevalence of cusp fractures in amalgam-restored teeth and resin-based composite-restored teeth is not significantly different. Teeth with more than one surface restored with either resin-based composite or amalgam and teeth in older subjects were more likely to suffer a cusp fracture.
  
  
  CONCLUSIONS
  Teeth restored with amalgam and with resin-based composite exhibited equally low cusp fracture prevalence. When choosing between amalgam and resin-based composite in consideration of the likelihood of a future cusp fracture, either restorative material is acceptable.
authors.affiliation: Wahl Family Dentistry, Wilmington, Del, USA. WahlMichaelJ@aol.com
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Wahl
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Schmitt
authors.forename: Donald A
authors.initials: DA
authors.lastname: Overton
authors.forename: M Kathleen
authors.initials: MK
authors.lastname: Gordon
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003188:Composite Resins / Q000009:adverse effects; D003723:Dental Amalgam / Q000009:adverse effects; D003793:Dental Restoration, Permanent / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019228:Tooth Crown / Q000293:injuries; D014082:Tooth Fractures / Q000209:etiology*
chemical_list: D003188:Composite Resins; D003723:Dental Amalgam