Introduction: caries is the most common chronic disease in childhood. The presence of caries in the primary dentition is the main risk factor for developing caries in the permanent dentition. Most of the risk factors for caries are modifiable and can become elements for the prevention and control of the disease. With the aim to reduce the incidence of caries in children at the age of 18 months, an interdisciplinary primary prevention intervention is designed for families with children following the pediatric health program “Protocol d’activitats preventives i de promoció de la salut a l’edat pediàtrica” (PAPPS). Methodology: non-randomized clinical trial, carried out in two primary care centers in Catalonia from January 2019 to June 2022. In one of the centers, an educational intervention for primary prevention of caries was designed and implemented with advice and skills to the families. In the other center, the usual protocol of recommendations was maintained. The incidence of caries was evaluated and compared in both groups at the age of 18 months with a logistic regression model estimated with the R program. Results: the incidence of caries at 18 months was higher in children in the control group (OR=6.0; 95% CI 1.8-20.2), despite the fact that the caries risk assessment based on the called “Caries Management by Risk Assessment” (CAMBRA) indicated a higher risk of caries in infants in the intervention group. Conclusion: the interdisciplinary primary caries prevention intervention incorporated into child health programs reduces the incidence of caries in the first years of life.