Dental floss selection and its impact on evaluation of interproximal contacts in licensure exams

Ideal interproximal contacts between adjacent natural teeth or dental restorations are a critical factor for the health of the dental-alveolar complex. Interproximal contact tightness is a physiological entity affected by many patient-related and restorative parameters. This variation poses a challenge in defining the "clinically acceptable" contact area tightness (CAT) and therefore how students and clinicians should be trained to evaluate this parameter. The most widely used method to evaluate interproximal contacts is to pass dental floss between contact areas. Candidates for licensure exams are instructed to check contact areas with dental floss and are advised that this will be one of the crucial parameters to be evaluated in the overall restoration quality. The purpose of this study was to evaluate a standardized interproximal contact with six brands of dental floss. Thirty faculty members and thirty dental students at one U.S. dental school evaluated the tightness of a single interproximal contact on a typodont. The results showed that no difference was found between CAT evaluations by faculty and students, whereas significant differences were found between different floss brands. In light of the results, it is suggested that licensure boards should standardize the recommendation for which floss brand should be used in order to avoid inconsistencies in students' preparation.