Congruence between self-reported and actually provided prosthodontic services among Swedish dentists

The purpose of this study, comprising two parts, was to investigate the congruence between answers given by general dentists in questionnaires concerning prosthodontic services and the recorded information on the services actually performed by each dentist. In Part I it is investigated whether questionnaire reports of weekly working hours devoted to prosthodontics can be used as indicators of actual prosthodontic production. Part II deals with the dentists' self-reported numbers of single crowns, fixed partial dentures (FPDs), and removable dentures. These reported services are compared with the services actually provided. Part I: A regression analysis indicates a lacking precision for the individual dentist, indicated by a relatively low explained variance (R2 = 0.20). However, a highly significant association is seen between the two production measures (P = 0.000). Part II: The congruence between stated and actually provided services is higher for single crowns and removable dentures than for FPDs. Bivariate regression models are statistically significant for all three services. In Part II, the reported weekly working hours used for prosthodontics covaries significantly with prosthodontic production, but the association is not as strong as in Part I. Although the precision in both Part I and Part II is low for the individual dentist, the questionnaire measure is found to be useful as an indicator in a population of dentists. It is concluded that the questionnaire data can be used as reasonably valid expressions of prosthodontic activity in population-oriented analyses among general dentists.