title: A controlled clinical study of amalgam restorations: survival, failures, and causes of failure.
abstract: The survival and modes of failure of amalgam restorations were investigated retrospectively. 2660 Class I or II lesions were restored and evaluated yearly or half-yearly for failures during the 30- to 84-month follow-up. Restorations with unacceptable margins were not counted as failures if no traces of secondary caries could be seen. 8% of the restorations were lost because of patient drop-out. Of the remaining restorations, 1% was replaced due to primary caries. Of the remaining number (2431), 9% failed because of all other reasons. The leading mode of failure was bulk fracture (4.6%), followed by tooth fracture (1.9%), and marginal ridge fracture (1.3%). For all other reasons, 0.8% of the restorations failed. Only two restorations were replaced because of secondary caries. The alloy selection in both conventional and high-copper categories significantly influenced the survival of the restorations for reasons directly related to the restoration.
authors.forename: H
authors.initials: H
authors.lastname: Letzel
authors.forename: M A
authors.initials: MA
authors.lastname: van 't Hof
authors.forename: M M
authors.initials: MM
authors.lastname: Vrijhoef
authors.forename: G W
authors.initials: GW
authors.lastname: Marshall
authors.forename: S J
authors.initials: SJ
authors.lastname: Marshall
mesh_terms: D003723:Dental Amalgam; D003793:Dental Restoration, Permanent / Q000706:statistics & numerical data*; D005069:Evaluation Studies as Topic; D005500:Follow-Up Studies; D006801:Humans
chemical_list: D003723:Dental Amalgam