The Effectiveness of an Oral Health Education Programme of Adolescents in Hong Kong
Condition: Caries, Dental; Periodontal Diseases
MeSH terms: Periodontal Diseases; Dental Caries
Study type: Interventional

Summary: 
      This project aims to evaluate the relative efficacy of a peer-led intervention based on the
      Social Cognitive Theory and Health Belief Model versus the control (only pamphlet delivery)
      on increasing the prevalence of healthy oral behaviors and oral health status among
      adolescents in Hong Kong. A two-arm non-blinded randomized controlled trial will be conducted
      among random samples of adolescents enrolling in secondary schools in Hong Kong. In addition
      to a baseline survey, two follow-up evaluative surveys will be conducted at months 6 and 12.
      Survey questionnaires will be conducted to participants at three time points (baseline, 6-,
      12-month follow-up). Dental check-up examinations will be evaluated at two time points
      (baseline, 6-month follow-up). Repeated measures will be used to record participants'
      background, oral behaviors, theory based cognition, and potential confounders. Validated
      scales will be used. DMFT, plaque index and CPI index will be used to assess the oral health
      status of participants.
    

Detailed description: 
      Baseline survey and dental examination The baseline survey will collect information on
      participants' background characteristics (e.g., socio-demographics), Social Cognitive Theory
      (SCT)-related variables (perceived susceptibility, perceived severity, perceived benefits,
      perceived barriers, self-efficacy), Health Belief Model (HBM)-related variables (reciprocal
      determinism, behavioral capability, outcome expectations), and oral health behaviors.
      Validated scales have been identified and will be used in the survey.

      To comprehensively assess each participant's oral health status at baseline, their oral
      hygiene status, caries experience and periodontal condition will be recorded following the
      recommendations of the World Health Organization (WHO) for oral health surveys. Oral hygiene
      status will be recorded through plaque index (PI) (Quigley Hein, 1972) on a scale of 0 to 5.
      Dental caries experience will be recorded by counting the numbers of permanent teeth that are
      decayed (DT), missing due to caries (MT), and filled (FT) to generate a DMFT score.
      Periodontal condition will be recorded using the Community Periodontal Index (CPI). Two
      trained and calibrated examiners (kappa = 0.81 - 0.87 for intra- and inter-examiner
      reliabilities for the assessment of DMFT and CPI) will perform the clinical examinations
      using a plane disposable plane intra-oral mirror with a built-in LED light source and a WHO
      CPI periodontal probe. Ten percent of the participants will be randomly selected and
      re-examined in each school to continuously monitor intra- and inter-examiner reliabilities of
      assessing PI DMFT and CPI.

      Intervention description A total of five peer-led activities will be conducted in the
      intervention schools by the well-trained peer leaders within a 6-month intervention period.

        1. In the 1st month of intervention, peer leaders will deliver a poster and a leaflet
           providing information on healthy oral behaviors based on SCT and HBM. Such materials
           will be provided at the entrance of the school gate, the canteen, and each class. Peer
           leaders will encourage students to ask questions when they receive such materials.
           Participants are free to take an on-site quiz to check assess their knowledge level.

        2. In the 2nd month of intervention, peer leaders will give a specific health talk aiming
           to raise the awareness of healthy oral behaviors. Schools teachers will encourage all
           students to participate in this talk. We will video-record this health talk and make it
           available online to reach more students. This talk will be guided by SCT and HBM, and it
           will include short testimonials of the good experiences of the peer leaders when
           performing healthy oral behaviors.

        3. In the 3rd month of intervention, peer leaders will organize a workshop aiming to help
           the participants practicing skills in performing healthy oral behaviors. Regarding
           different oral behaviors (tooth brushing, dental flossing, and dental visits), targeted
           skills will be practiced.

        4. In the 4th month of intervention, peer leaders are encouraged to self-design and conduct
           one more oral health-related activity that they are interested. Necessary support will
           be provided by the team. We will record details of this peer leader-initiated activity.

        5. In the 5th or 6th month of intervention, peer leaders will deliver a special talk
           regarding illness representations for students with existing oral diseases only. The
           talk will focus on improving illness representation in both cognitive and emotional
           aspects, and coping strategies will be practiced.

      The first follow-up at months 6 The first follow-up at months 6 will include two parts. The
      first part is to collect participants' self-reported data through questionnaire. An
      experienced fieldworker will facilitate the survey process, and she will be blind to our
      group allocation. The month 6 follow-up data suggest an immediate impact of the intervention,
      as all intervention activities will be conducted within this 6-month intervention period. The
      proposed time interval (6 months) is reasonable and feasible, as 6 months is the most
      frequently adopted time frame to assess behavior changes and the dental visit for check-up
      (one of our primary outcomes) is recommended to adolescents every 6 months. We will compare
      changes before and after this intervention within interventions group, and we will also
      investigate the differences between intervention group and control group.

      The second follow-up at months 12 The second follow-up at months 12 will include two parts.
      The first part is to collect participants' self-reported data through survey, the same
      procedure as the first follow-up at month 6. The month 12 follow up data suggest a prolonged
      impact of the intervention, as no intervention activities will be conducted between months 6
      and months 12.

      The second part is to do dental re-examination, using the same methods and criteria as the
      baseline examination. We will compare the disease status changes before and after
      intervention within interventions group. The consistency between self-reported healthy oral
      behaviors and dental examination outcomes will also be calculated. No dental examination will
      be conducted at month 6 follow up, as oral disease status is not likely to change within a
      short time period like 6 months.

      Data analysis The intra- and inter-examiner reliabilities of assessing PI, DMFT and CPI at
      the tooth level will be tested through the use of the kappa statistic. Data of DMFT and CPI
      at the tooth level will be used to generate the oral disease status at the subject level.

      Intention-to-treat analysis will be conducted. Multiple imputation methods will be used to
      deal with missing data if it occurs. Between-group (intervention versus control) baseline
      differences in the frequency distributions of potential confounders will be compared by using
      chi-square test, t-test, Mann-Whitney test or other statistics. The absolute and relative
      risks and number needed to treat (and their 95% confidence intervals) for the binary outcomes
      comparing the two groups at months 6 and 12 will be derived. Adjusted comparisons between the
      intervention and control groups will be made for all binary outcomes, adjusting for any
      potential confounders showing p<.10 in the between-group baseline comparisons (if any), using
      modified Poisson regression with robust sandwich variance estimation. SPSS will be used for
      data analysis; p<.05 (2-sided) will be taken as statistically significant.
    

Intervention name(s): peer-led theory-based intervention group
Intervention type(s): Behavioral
Intervention description(s): We plan to select 2-8 peer leaders in S2 students within each school in the intervention group. A total of 25-48 peer leaders will be selected and trained in this study.
An experienced behavioural scientist will train the peer leaders through lectures, workshops, and individual counselling.
A total of 6 hours training (3 hours per day x 2 days) will be conducted during weekends. Peer leaders will practice in groups, and only those who pass the evaluation are allowed to conduct peer-led interventions. We will record the performance and give specific feedback to each peer leader.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Investigator, Outcomes Assessor)
Primary purpose: Supportive Care