Variation in dentist service rates in a homogeneous patient population.

Previous studies in medicine and dentistry document wide variations in service rates across small areas, large regions, and providers. The practice patterns of providers and underlying differences in patient need are thought to be important sources of this variation. To control for variation in patient needs, we calculated service rates of 200 general dentists in Washington state based on a homogeneous, well-educated, upper-middle-class population of patients. Wide variations were found in the rate for many dental services. Dentists' practice beliefs and characteristics of the practice were sources of variation in the rates. The evidence is insufficient to determine whether undertreatment of overtreatment occurred among dentists with the lowest and highest expenditures per patient, respectively. However, the perceived oral health status of adult patients was lower in practices with the lowest total expenditures per patient than in practices with the highest total expenditures per patient, suggesting the undertreatment of adult patients in the lowest-expenditure practices may have occurred.