Oral health of 6–7 year-old children according to the Caries Assessment Spectrum and Treatment (CAST) index

BACKGROUND: The index of Caries Assessment Spectrum and Treatment (CAST) reveals a range of caries development from a non-cavitated status to advanced lesions. The aim of the present study was to explore the oral health status of 6- to 7-year-old children based on the CAST index in relation to oral health knowledge and background determinants. METHODS: A multi-stage cluster random sampling method was applied and after ethical clearance, clinical examination was performed (Kappa = 0.89). The status of caries and oral hygiene was recorded according to the CAST index and OHI-Simplified (OHI-S) index, respectively. A self-administered questionnaire was used to collect the data of parental knowledge of oral health. SPSS version 22.0 was used for data analysis and p-value less than 0.05 were considered significant. RESULTS: Seven hundred and thirty-nine children and their parents in 24 schools participated in this study (88%), of whom 48.6% were boys and the rest were girls. In permanent molars, a healthy status (code 0–2) was observed in 89.3–93.7% of the teeth. In primary molar teeth, dentinal lesions ranged from 25.3 to 31.2%, the prevalence of pulp involvement was between 2.9 and 10.5%, and less than 1% had abscess/fistula. Serious morbidity (codes 6 and 7) were more common in the first primary molars than the second ones. Multi-variable logistic regression analysis indicated that children with a low level of father’s education were 2.45 times more likely to have a CAST score of 3 and higher (95% CI 1.35–4.46, p = 0.003) compared to children whose fathers had academic education. For each one-unit increment of OHI_S, the likelihood of a CAST score 3 and higher in primary dentition increased by 1.77 times (OR = 1.77; 95% CI 1.08–2.93, p = 0.02). CONCLUSION: The consequences of dental caries including abscess and fistula were more prevalent in the first and second primary teeth. There was a significant correlation between a CAST score of 3 and higher with father’s education (as an indicator of social rank) and oral hygiene status. The CAST index is a useful and practical index in epidemiological surveys. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12903-018-0709-x) contains supplementary material, which is available to authorized users.