Theory-guided school-based interventions may improve oral self care in adolescents


This cluster randomised control trial aimed to investigate if using a theory-guided intervention would be effective at improving the oral self-care of adolescents. The authors justified the study by noting that despite a wide range of literature available on behavioural interventions to improve oral health, very few had a sound theoretical foundation. This finding was noted in a Cochrane review of school based interventions for preventing caries in children and this study aimed to consider this problem using an adolescent population.


The study randomly selected two schools from an area of socio-economic deprivation, within these two schools classes were assigned to either the intervention, social-cognitive intervention, or the control, standard advice. Based on a sample size calculation 90 participants in each group were expected, the final sample had 98 participants in the intervention and 99 in the control group.

The intervention consisted of peer cooperation, peer interactive learning and facilitated feedback from a dentist though classroom session delivered over a period of three weeks. To measure the outcome variable disclosing solution was used to highlight areas of plaque, and this was photographed, coded and then marked by a blinded assessor for the percentage of the total teeth area covered by stained dental plaque. The control group were assessed at baseline, 6 month follow up and 12months. The intervention group were also assessed at these intervals and following the intervention. Additionally, a questionnaire related to self-efficacy domains was distributed at baseline, 6months and 12months.


  • 197 adolescents were recruited ( 98 to intervention, 99 to control group)There was a high degree of lost to follow up with only 71 of the intervention and 68 of the control group being assessed at 12 months, this equates to a loss of around 30% of the total study population.
  • At baseline there was no statistical difference between the control and intervention group mean ± SD plaque levels
    • Control 33.2 ± 17.5 Intervention 29.7 ± 19.2
  • 6 months following the intervention a statistically significant difference between the mean± SD plaque levels was noted between the control and intervention group
    • Control 35.1 ± 20.0 Intervention 27.4 ± 19.4
  • 12 months following the intervention there was not statistically significant difference between the mean± SD plaque levels in the control and intervention group
    • Control 31.9 ± 17.8 Intervention 27.4 ± 18.5
  • There were some key factors which explained a high degree of the variability in plaques levels across different time points these were, family socio-economic status, baseline plaque level and social-cognitive domain variables.


The authors concluded:

Social-cognitive theory-guided interventions improved oral self-care of adolescents in the short term. After the intervention was discontinued, the improvement in oral self-care of adolescents lasted for another 5 months.


This paper has some methodological weaknesses, the calculation of sample size for example, was based on the number of individuals rather than taking into consideration the impact of clustering. Consequently the study is likely to have been under powered from the outset.

Additionally, the reporting of the randomisation process was limited did not conform to the standards expected by CONSORT. or Cochrane. There was a significant risk of contamination between control and intervention groups as both groups were present with each school and this may have been compounded by the different treatment of the two groups during the study.

Questions could be raised over clinical importance of the outcome measure, would a general dental practitioner consider a 2-3% change in the amount of plaque present as a significant change in oral self care?

Despite these limitations it does provide a useful starting point for discussion. Adolescents are a largely forgotten population group in the promotion of oral health, with current effort and focus on younger children. If we consider the development of evidence this initial trial paves the way for future research prompting consideration of what might be the best approach to supporting this population group and what we can learn from existing work with younger children and adults.


Primary paper

Aleksejuniene J, Brukiene V, Dziaugyte L, Peciuliene V, Bendinskaite R. A theory-guided school based intervention in order to improve adolescents’ oral self care: a cluster randomised trial. Int J Paediatr Dent, 2015, April 2016. Doi: 10.1111/ipd.12164 (e-publication ahead of print).

Other references

Cooper AM, O’Malley LA, Elison SN, Armstrong R, Burnside G, Adair P, Dugdill L, Pine C. Primary school-based behavioural interventions for preventing caries. Cochrane Database of Systematic Reviews 2013, Issue 5. Art. No.: CD009378. DOI: 10.1002/14651858.CD009378.pub2.

CONSORT checklists. Randomisation: sequence generation. 

Share on Facebook Tweet this on Twitter Share on LinkedIn Share on Google+