Objectives: Determine prevalence and severity of dental caries in school-going children of a remote Indigenous community following 6 years passive and 2 years active prevention. Methods: Children from preparatory, primary and secondary schools were surveyed in 2004, one year before Community Water Fluoridation (CWF), in 2012 following 6 years of, and 1 year post, cessation of CWF, a further 3 years post-cessation in 2015 and in 2016 and 2017 following 1 and 2 years active prevention (NHMRC APP1081320). The latter consisted of annual application of fissure sealant, povidone-iodine and fluoride varnish. 2004 and 2012 surveys used WHO Basic methodology: the 2015-17 surveys ICDAS-II. Results: Age-weighted overall caries severity, dmft/DMFT, declined 2004 to 2012 for children aged 4-15 by 37.9% in deciduous (DD) and 36.6% in permanent (PD) dentitions, attributable to CWF. Between 2012 and 2015 an increase of 23.6% and 7.7%, respectively, were found. Age-weighted prevalence (dmft>0; DMFT>0) decreased from 2004 to 2012 by 4.2% and 6.4% respectively for the DD and PD and by a further 1.3% and 0.5% respectively, 2012 to 2015. After 2 years of active prevention, caries severity for the experimental group decreased by 13.7% in DD and 26.6% in PD. Caries prevalence decreased by 4.9% and 3.8% respectively for the DD and PD during this time. Conclusions: Decline in caries prevalence and severity after introduction of CWF was followed by an increase in severity, 4 years after cessation, for both dentitions. Mean annual decline in caries severity for both dentitions for the 2 years of active prevention exceeded that for passive prevention. Nevertheless, untreated caries remains a problem in both dentitions during both passive and of active intervention. Due to remoteness, cost and logistics in ensuring long-term viability of an active preventive program, CWF remains necessary in this type of community.