Dental caries trends and inequalities in Brazilian schoolchildren: 40 years of study (1971 – 2011)

INTRODUCTION: The dental caries decline is a result of several social and public health measures. Such decline has been followed by the increase of inequality, since few individuals have most dental diseases, and their peers are caries-free or show a small amount of dental lesions. This study aimed to estimate the prevalence, severity, and inequality in the distribution of dental caries in schoolchildren from Florianópolis, Brazil, for the past 40 years (1971 – 2011).

METHODS: All 12- and 13-year-old schoolchildren enrolled in a public school were eligible. Decayed, missing and filled teeth (DMFT) index, the Significant Caries Index (SiC) and the Gini coefficient (to assess inequalities in the distribution of dental caries) were estimated.

RESULTS: The response rate was 100% in 1971 (n=202) and 1997 (n=175), 93.8% in 2002 (n=169), 90% in 2005 (n=171), 68.2% in 2009 (n=101) and 82.3% in 2011 (n=130). The prevalence of dental caries decreased from 98.0% (95% CI 96.0–100.0) in 1971 to 36.9% (95% CI 28.5–45.3) in 2011. The mean DMFT ranged from 9.2 (95% CI unavailable) in 1971 to 0.67 (95% CI 0.5–0.9) in 2011. The Gini coefficient was 0.624 in 2002, but increased to 0.725 in 2011. The Lorenz curve showed that 70-75% of the dental caries attack was restricted to 20% of the population in 2011. A reduction of 41.2% in the mean SiC index was observed between 2002 (3.4, 95% CI 3.0–3.8) and 2011 (1.9, 95% CI 1.6–2.1). 

CONCLUSIONS: Despite the decline, a proportion of the population has been concentrating most of the dental caries burden. Research should bring attention to those individuals with higher caries attack and focus on the neglected groups. An oral health surveillance system is important and may help to assess the effectiveness of oral health policies.