Dental caries experience in children of a remote Australian Indigenous community following passive and active preventive interventions

Objectives: To report on changes in dental caries experience in children of a remote Indigenous community following 6 years of passive preventive intervention (PPI) and 2 years of active preventive intervention (API). Methods: Five consecutive cross-sectional surveys were conducted on 4- to 15-year-old school going children between 2004 and 2017 following phases of Community Water Fluoridation (CWF), post-cessation of CWF and API. Following treatment of any cavities present, API included selective placement of fissure sealants (FS) and an annual application of povidone-iodine (PI) and fluoride varnish (FV). The World Health Organization's (WHO) "Oral Health Surveys - Basic Methods (4th Edition)" methodology was used in the first two and the International Caries Detection and Assessment System (ICDAS-II) in the latter three surveys. ICDAS-II codes of 3-6, representing advanced caries, were combined to allow comparison to the decayed component of the DMF caries index. Results: Age-weighted mean dmft decreased by 37.7% in the deciduous (DD) and DMFT by 35% in the permanent (PD) dentitions between the pre- and post-CWF surveys, followed by increases of 25% and 7.7%, respectively, between the 1-year and 4-year post-CWF surveys. After 2 years of API, mean dmft decreased by 14.3% and DMFT by 7.1%. Untreated dental caries however remained a concern in the DD and PD during both phases of PPI and of API. The decline in caries experience for both dentitions following 2 years of API exceeded that for the 6-year period of PPI. Conclusions: The annual reductions in caries experience of 7.2% (DD) and 8% (PD) during the phase of API exceeded annual decreases of 4.7% (DD) and 4.6% (PD) during the phase of PPI. Due to remoteness, cost and logistics in ensuring long-term viability of API programmes, CWF remains necessary in this type of community.