title: School-based education to improve oral cleanliness and gingival health in adolescents in Tehran, Iran.
abstract: BACKGROUND
  Schools can be an important setting for health education programmes, controlling the growing burden of oral diseases and promoting oral health. Aim. The aim of this study was to evaluate the short-term effect of school-based educational intervention on oral cleanliness and gingival health of 15-year-olds in Tehran, Iran.
  
  
  METHODS
  The present cluster randomized trial was based on exposing students (n = 287; control, n = 130) at public schools to oral health knowledge through a leaflet or a videotape. The outcome was evaluated after 12 weeks. A positive outcome was defined as at minimum a 50% reduction in numbers of teeth with dental plaque or gingival bleeding compared to baseline. Evaluation included percentage changes, number needed to treat (NNT), and students' self-assessment.
  
  
  RESULTS
  At baseline, all students had dental plaque, and 93% had gingival bleeding on at least one index tooth. Positive outcome for oral cleanliness was 58% (P < 0.001) of the students in the leaflet group, 37% (P < 0.001) in the videotape group, and 10% of controls. Corresponding figures for gingival health were 72% (P < 0.001), 64% (P < 0.001), and 30%. For oral cleanliness, NNT was 2 in the leaflet and 3 in the videotape group; for gingival bleeding, NNT in both groups was 3. More than two-thirds of the students assessed their oral health behaviours as having improved moderately.
  
  
  CONCLUSIONS
  An easy-to-organize and inexpensive school-based intervention can in the short term be effective in improving oral cleanliness and gingival health among adolescents; in particular, in countries with a developing oral health system.
authors.affiliation: Institute of Dentistry, University of Helsinki, Helsinki, Finland. reza.yazdani@helsinki.fi
authors.forename: Reza
authors.initials: R
authors.lastname: Yazdani
authors.forename: Miira M
authors.initials: MM
authors.lastname: Vehkalahti
authors.forename: Mahtab
authors.initials: M
authors.lastname: Nouri
authors.forename: Heikki
authors.initials: H
authors.lastname: Murtomaa