Evaluation of the impact of a mass media campaign on periodontal knowledge among Iranian adults : a three-month follow-up

Objectives This study aimed to evaluate the impact of a national media campaign to promote oral health and periodontal knowledge among adults after a three-month follow-up. Methods We conducted a population-based study of adults aged 18 to 50 years using a stratified multi-stage sampling method in Tehran, Iran in 2011. The campaign included an animation clip about periodontal health and disease telecast on national TV for ten consecutive days. We used an instrument to assess the effect of the campaign at baseline, immediately after the campaign and after a three-month follow-up. A total of 543 participants responded at baseline and immediately after the intervention, and 294 were interviewed at the three-month follow-up assessment (response rate: 54.1%). We assessed each participant’s periodontal knowledge score, calculated as a sum of correct answers, and the change in their score following the campaign. We then used a five-item questionnaire to evaluate the participants’ opinion of the success of the campaign. We used descriptive statistics and generalised estimating equations (GEE) analysis to conduct the statistical analysis. Results The mean score for knowledge improvement from baseline to immediate post-intervention evaluation was higher among those who saw the campaign (0.61) than among those who did not (0.29); the corresponding figures from immediate evaluation to three-month follow-up were -0.17 and 0.15, respectively. Adjusting for baseline values, the GEE analysis demonstrated that improvement in the mean score of post-campaign knowledge associated significantly with age, education and seeing the campaign. Significant interaction between the time since seeing the campaign and whether the participant saw it (p < 0.001) revealed that the mean difference in the knowledge score between the groups who did and did not see the campaign was 0.4 at the immediate evaluation and -0.04 at the three-month follow-up. The participants received the campaign well in terms of being appealing (91.4%), worth bearing in mind (83.4%) and containing valuable information (80.3%). Conclusions Our findings indicate that a population-based media campaign promoting oral health and periodontal knowledge among adults had a positive short-term impact, although the effect seemed to plateau after three months.