Caries status of first-born child is a predictor for caries experience in younger siblings

OBJECTIVES: This study analysed if children of families in need of dental interventions can be identified by using the caries status of the first-born child as a predictor for caries in younger siblings of the same family. MATERIAL AND METHODS: All children aged 4 to 15 years, i.e. 13,596 children, visiting a compulsory school in the canton of Basel-Stadt, Switzerland, during the school year 2017/2018 were analysed. Total caries experience and untreated carious lesions at time of examination were recorded as well as a subset of socioeconomic factors such as gender, age, nationality, birth order and the family's place of residence. RESULTS: A total of 6738 schoolchildren who had at least one sibling of school age could be included. Differences in caries experience and the presence of active carious lesions were found for age, nationality and place of residence but not for gender or birth order. Younger siblings had odds of having a history of caries 3.7 times higher (95% confidence interval: 3.0-4.4) and odds of having active carious lesions 3.5 times higher (95% confidence interval: 2.6-4.7) if the eldest child in the family already had caries. CONCLUSION: Caries could be shown to be family-dependent. Younger siblings had a more than three-fold higher risk for caries if the first-born child already had carious lesions. CLINICAL RELEVANCE: Based on these results, the caries status of the first-born child could be used as a potential indicator to detect vulnerable families and to initiate targeted preventive measures.