Effectiveness of Fluoride Varnish in Prevention of Dental Caries in School Children
Condition: Dental Caries
MeSH terms: Dental Caries
Study type: Interventional
Phase: Phase 1/Phase 2

Summary: 
      Despite the availability of free health dental service in Sri Lanka, the prevalence and
      severity of dental caries among 6year old school children stand at a very high level
      according to the results of national oral health survey in 1983/84, 94/95 and 2002/2003.
      Professional fluoride varnish application has become popular as variety of studies has found
      that it is an efficient method in reducing dental caries. The simplicity of its application
      makes it very suitable and practical for use in dental clinics and outreach dental services,
      especially in young children.

      Aim of this study is to evaluate the cost effectiveness of 6 monthly application of sodium
      fluoride varnish in prevention of dental caries in permanent incisors and molars in children
      between 6 and 7 years in a suburban setting in Sri Lanka. This will be a double-blind,
      randomized controlled trial. A sample of school children (6-7 years) will be randomized into
      varnish and control groups. All the children will receive routine caries preventive measures
      of oral hygiene instructions, dietary advice and professional cleaning. Children in varnish
      group will receive fluoride varnish professionally applied after prophylaxis every 6 months.
      Clinical examinations of all children will be performed at the beginning of the study and 1
      year and 2 years later. All the caries at the dentinal level of both groups will be
      stabilized with temporary restorations at the beginning. During this period, each school will
      be visited four times at 6-month interval for recruitment, dental examinations, and fluoride
      varnish applications. Recruited children will be randomly assigned to either a treatment (5%
      NaF varnish) or a control group. Caries examinations will be conducted using the
      International Caries Detection and Assessment System (ICDAS). The cost for the dental team's
      school visits; cost involved in the treatment of dental caries throughout the course of the
      study in both groups will be evaluated and compared at the end of the study. The sample size
      is calculated as 160 each arm to detect 5% caries change with 80% power. Analysis The effect
      of intervention will be measured by number of caries prevented. New caries in the usual care
      and intervention group will be calculated after the completion of the study. The costs for
      intervention will be estimated. The costs will be estimated for the dental material, time for
      human resources and indirect costs.
    

Detailed description: 
      Background

      Dental caries remains a significant public health problem with socioeconomic, dietary and
      microbiological factors playing a major role as risk factors in initiation and progression of
      the disease. It is the most common cause of toothache and hospital admissions in young
      children. Dental caries in school children not only causes pain, but also impacts school
      attendance, parents' work hours, children's ability to eat, play and sleep. Therefore, dental
      caries when present significantly reduces the health related quality of life of a child.

      Evidence-based studies indicate oral health prevention is cost-effective and saves children
      from pain and lost days of school.Therefore the measures taken to prevent the develop¬ment of
      dental caries could include bacterial biofilm control, dietary counselling, fluoride
      toothpastes, mouth rinses, varnishes, gels and foams, and casein-derived remineralisation
      pastes and placing resin-based/glass-ionomer pit and fissure sealants. ) Professional
      fluoride varnish application has become popular as variety of studies has discussed its
      effect in reducing dental caries.

      Fluoride varnish was incorporated into clinical dentistry to reduce caries; its use in the
      U.S. has increased progressively since it was approved by the FDA in 1994. Fluoride varnish's
      effectiveness in caries prevention, ease of application, and safety give it an advantage over
      other types of topical fluoride treatments (such as gels and rinses) or other caries
      management methods. As a result, it is regarded as one of the superior topical fluoride
      agents for young children. Fluoride varnish also prolongs the contact time between fluoride
      and tooth surface to reduce caries. Its active ingredient is usually 5% sodium fluoride, or
      22,600 ppm fluoride. It also has recently gained much attention in dentistry because the risk
      of dental fluorosis is also minimal.The simplicity of its application makes it very suitable
      and practical for use in dental clinics and outreach dental services, especially in young
      children and in other special needs groups.

      Justification

      Despite the availability of free health dental service in Sri Lanka, the prevalence and
      severity of dental caries among six and seven years old school children in Sri Lanka stand at
      a very high level according to the results of national oral health survey in 1983/84, 94/95
      and 2002/2003. The prevalence is 78% (83/84), 76.4% (94/95) and 65.5% (2002/2003) whereas the
      dmft is 4.4, 4.1 and 3.6.

      The simplicity of its application makes it very suitable and practical for use in dental
      clinics and outreach dental services, especially in young children and in other special needs
      groups.

      Up to date there is no other study carried out on cost effectiveness of fluoride varnish
      application on teeth in Sri Lankan population. Therefore, the results of the study will be
      beneficial in implementation and identification of advantages of fluoride varnish application
      on teeth in young children.

      Aim

      the main objective of this study was to evaluate the effectiveness of six monthly application
      of sodium fluoride varnish in prevention of dental caries in deciduous teeth, permanent
      incisors and molars in children between six and seven years in Sri Lanka.

      The specific objective is:

      1. To find out the association between dental caries and the social status of the child (e.g.
      mother's education, father's education, monthly family income etc.)

      Methods

      This was a double-blind, randomized controlled trial. The study has been registered with
      clinical trials registry (NCT02877888).

      The study population was school children aged six to seven years, living in Kurunegala
      district. The inclusion and exclusion criteria used in the study are described below. The
      study was conducted at Maliyadeva Adarsha Vidyalaya and Wayamba Royal college, Kurunegala
      from month year to month year. The sample was selected according to below criteria…

      Inclusion Criteria:

        -  Children with at least one permanent tooth present.

        -  Age 6 to 7 years. Children under 6 years of age were enrolled in the study if at least
           one permanent tooth has erupted.

        -  Residing in Kurunegala municipal council region and tap water is consumed (fluoride
           levels in drinking water was considered similar).

      Exclusion Criteria:

        -  Children with ulcerative gingivitis and stomatitis. (These children were referred for
           treatment.)

        -  No permanent tooth present or stainless steel crowns only.

      The students meeting the inclusion and exclusion criteria was randomly assigned, using block
      randomization in blocks of four, using a computer generated set of random numbers, to either
      varnish (5% Sodium Fluoride) or control group. A set of random numbers was used to create an
      allocation sequence, which was contained in individual opaque envelopes for used by the chief
      investigator. As the patients were recruited, the next envelope in the sequence was opened
      and the student was assigned to the stated group. All randomisation, sequence generation, and
      preparation of group allocation materials was performed by a third party who had no direct
      contact with the clinical aspects of the trial.

      The sample size was calculated as 160 each arm to detect 5% caries change with 80% power. All
      children in both groups were provided with a self-administered pre tested questionnaire to
      assess the quality of life associated with presence of dental caries. Further, all the
      children received routine caries preventive measures of oral hygiene instructions, dietary
      advice and professional cleaning. Clinical examinations of all children were performed at the
      beginning of the study and 1 year and 2 years later. All the caries at the dentinal level of
      both groups were stabilized with temporary restorations at the beginning. Both varnish and
      control groups were subjected to use of fluoride tooth paste of 1000ppm. Children in the
      intervention group received fluoride varnish professionally applied after prophylaxis every 6
      months combined with counselling on maintenance of oral hygiene and diet for a period of 2
      years. The control group was only subjected to counselling on maintenance of oral hygiene and
      diet.

      During the period of two years, a team visited each school four times at six months' interval
      for recruitment, dental examinations, and fluoride varnish applications. Trained interviewers
      collected data on oral health habits and sociodemographic characteristics of the children.
      Caries examinations were conducted using the International Caries Detection and Assessment
      System (ICDAS).

      The primary outcome studied was the number of new caries in the two study groups. Students
      and the interviewers were blinded to the intervention (varnish application or control) and
      they were blinded to the hypothesis, which was investigated in this study.

      Analysis

      The mean number of caries between different groups, segregated according to the variables
      assessed in the study, were compared. The mean number of caries in a particular group was
      calculated by dividing the total number of caries in a particular group by the total number
      of students in that group. As the number of caries showed a skewed distribution, Mann-Whitney
      U test was used compare the groups. Level of significance was considered as p<0.05.

      The effect of intervention was measured by the mean number of new caries in different groups.
      The number of new caries in the usual care and intervention group was calculated at each time
      point of the survey. The mean number of new caries between the two groups were compared using
      Mann-Whitney U test. To assess the independent effect of the intervention on the incidence of
      caries, when other factors are controlled, multiple linear regression was applied.
    

Intervention name(s): fluoride varnish 22600ppm
Intervention type(s): Drug
Intervention description(s): topical application on teeth every 6months
Other intervention name(s): 5% duraphat
Intervention MeSH terms: Fluorides; Fluorides, Topical
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Investigator, Outcomes Assessor)
Primary purpose: Health Services Research
Keywords: cost effectiveness; fluoride varnish; dental caries