The cost-effectiveness of large amalgam and crown restorations over a 10-year period

To assist clinical decision making for an individual patient or on a community level, this study was done to determine the differences in costs and effectiveness of large amalgams and crowns over 5 and 10 years when catastrophic subsequent treatment (root canal therapy or extraction) was the outcome.

Administrative data for patients seen at the University of Iowa, College of Dentistry for 1735 large amalgam and crown restorations in 1987 or 1988 were used. Annual costs and effectiveness values were calculated. Costs of initial treatment (large amalgam or crown), and future treatments were determined, averaged and discounted. The effectiveness measure was defined as the number of years a tooth remained in a state free of catastrophic subsequent treatment. Years free of catastrophic treatment were averaged, and discounted. The years free of catastrophic treatment accounted for individuals who dropped out or withdrew from the study.

Teeth with crowns had higher effectiveness values at a much higher cost than teeth restored with large amalgams. The cost of an addition year free of catastrophic treatment for crowns was 1088.41 dollars at 5 years and 500.10 dollars at 10 years. Teeth in women had more favorable cost-effectiveness ratios than those in men, and teeth in the maxillary arch had more favorable cost-effectiveness ratios than teeth in the mandibular arch.

Neither the large amalgam or crown restoration had both the lowest cost and the highest effectiveness. The higher incremental cost-effectiveness ratio for crowns should be considered when making treatment decisions between large amalgam and crown restorations.