Objective: To determine the experience, prevalence and severity of dental caries, as well as the Significant Caries Index (SiC) and the treatment needs (TN) in schoolchildren aged six to twelve years. Equally, to estimate the effect of caries in primary dentition on caries in permanent dentition.
Material and methods: A cross-sectional study was realized in 3865 schoolchildren from San Luis Potosí City, Mexico. Subjects were clinically evaluated by three standardized examiners (kappa > 0.85). For detection of caries was employed the WHO's criteria for primary (dmft) and permanent (DMFT) dentitions. In the statistical analyzes non-parametric test and logistic regression were used.
Results: Mean of age was 8.69 +/- 1.79 and 51.3% were women. In the primary dentition: dmft index was 1.88 +/- 2.34 and the caries prevalence (dmft >0) of 56.8%. In account to severity 22.0% and 5.6% have dmft >3 and dmft >6, respectively. In children of six years, the caries prevalence was 56.0% and the SiC of 5.45. In the permanent dentition: DMFT index was 1.11 +/- 2.03 and the caries prevalence (DMFT >0) of 36.8%. In account to severity 11.8% and 2.8% have DMFT >3 and DMFT >6, respectively. In children of twelve years, the DMFT index caries 4.14 +/- 4.15 and the SiC of 9.15. The TN index was of 88.5% for primary dentition and 93.6% for the permanent. In logistic regression we observed associated to caries prevalence in permanent dentition; presence of caries in primary dentition (OR = 6.37; p < 0.001), female sex (OR = 1.33; p < 0.001) and higher age (OR = 1.69; p < 0.001).
Conclusions: Caries prevalence to six years old and DMFT index to twelve years old were highest to values established by WHO. Caries severity in the primary dentition was two times than observed in the permanent dentition. High TN in both dentitions was observed. Presence of caries in primary dentition was a strong risk indicator for to present caries in permanent dentition.