Five-year treatment outcomes for teeth with large amalgams and crowns.

For 4735 posterior complex amalgams and crowns placed in adults with continuous dental HMO coverage, all additional treatment received over the subsequent 5 years was determined. The restorations were placed under routine clinical conditions by 74 different dentists among a broad spectrum of insured dental patients. Treatment outcomes were described in terms of a hierarchical classification of additional treatments. At the extremes, a successful outcome was defined as no additional treatment or an additional one- or two-surface restoration on the same tooth, and a catastrophic outcome as extraction or endodontic treatment. Due to clinical protocols, teeth with guarded to poor prognosis prior to treatment are overrepresented in the five-surface amalgam cohort. Successful outcomes characterized 72% of four-surface amalgams, 65% of five-surface amalgams, 84% of gold crowns, and 84% of porcelain crowns. Catastrophic outcomes occurred for 10% of four-surface amalgams, 15% of five-surface amalgams, 8% of gold crowns, and 9% of porcelain crowns.