Effectiveness of strategies to disseminate and implement clinical guidelines for the management of impacted and unerupted third molars in primary dental care, a cluster randomised controlled trial

Objective To investigate the effectiveness and cost-effectiveness of different guideline implementation strategies, using the Scottish Intercollegiate Guidelines Network (SIGN) Guideline 42 'Management of unerupted and impacted third molar teeth' (published 2000) as a model.

Design A pragmatic, cluster RCT (2x2 factorial design).

Subjects Sixty-three dental practices across Scotland. Clinical records of all 16-24-year-old patients over two, four-month periods in 1999 (pre-intervention) and 2000 (post-intervention) were searched by a clinical researcher blind to the intervention group. Data were also gathered on the costs of the interventions.

Interventions Group 1 received a copy of SIGN 42 Guideline and had an opportunity to attend a postgraduate education course (PBEC). In addition to this, group 2 received audit and feedback (A and F). Group 3 received a computer aided learning (CAL) package. Group 4 received A and F and CAL.

Principal outcome measurement The proportion of patients whose treatment complied with the guideline.

Results The weighted t-test for A and F versus no A and F (P=0.62) and CAL versus no CAL (P=0.76) were not statistically significant. Given the effectiveness results (no difference) the cost effectiveness calculation became a cost-minimisation calculation. The minimum cost intervention in the trial consisted of providing general dental practitioners (GDPs) with guidelines and the option of attending PGEC courses. Routine data which subsequently became available showed a Scotland-wide fall in extractions prior to data collection.

Conclusion In an environment in which pre-intervention compliance was unexpectedly high, neither CAL nor A and F increased the dentists' compliance with the SIGN guideline compared with mailing of the guideline and the opportunity to attend a postgraduate course. The cost of the CAL arm of the trial was greater than the A and Farm. Further work is required to understand dental professionals' behaviour in response to guideline implementation strategies.