Dental Caries and Extrinsic Black Tooth Stain in Children With Primary, Mixed and Permanent Dentitions: A Cross-Sectional Study.

Background: Dental caries and extrinsic black tooth stain (EBS) are prevalent among children, with current evidence suggesting a negative correlation between them. It is unclear whether the factors contributing to developing or preventing dental caries and EBS are connected or aligned.

Aim: To investigate the prevalence and associated factors of caries and EBS among children with primary, mixed and permanent dentitions.

Design: This was designed as a cross-sectional study. Probability proportionate to size sampling and simple random sampling methods were used to recruit children aged 5, 9 and 12. Three calibrated paediatric dentists conducted intra-oral examinations. Nutritional supplements, oral health-related behaviours and family background were collected. Bivariate analysis, negative binomial and binary logistic regression were performed.

Results: Caries and EBS prevalence were 83.7% and 4.7%, respectively. A decreasing trend in caries and an increasing trend in EBS prevalence were observed across three dentitions. Caries were associated with EBS, oral hygiene, vitamin intake, gender, food-pocketing habits, toothbrushing duration, dental attendance and socioeconomic status. EBS was more likely to occur in caries-free children (OR = 4.42, 95% CI 2.97,6.58, p < 0.001) and children without vitamin consumption (OR = 1.59, 95% CI 1.07, 2.36, p = 0.021).

Conclusion: The occurrence of caries and EBS varied across different dentition stages. Their risk and protective factors were not significantly aligned.