A long-term prospective, randomized dietary intervention to prevent exposure of children to the known atherosclerosis risk factors (the STRIP baby project) was started when the age of the children was 7 months. The aim of this substudy was to analyze the oral effects of the dietary intervention in the children and their parents when the children had reached the age of 3 years. Every fifth family of the main study was invited to this substudy (n = 179). Those studied (n = 148) represented well the intervention and the control groups and both genders in terms of intake of saturated fatty acids, the dietary polyunsaturated fatty acid to saturated fatty acid (PUFA/SAFA) ration and serum cholesterol and HDL cholesterol concentrations. Though no difference was found in sucrose consumption between the intervention and the control groups, the intervention children received relatively (in E%) more energy from carbohydrates than the control children (p < 0.005), used absolutely (in g) and relatively (in E%) less fat (p < 0.05) and had a higher PUFA/SAFA ratio in their diet (p < 0.001). Of the 3-year-old children 93% were caries free, and dental decay was a prevalent in the intervention as in the control children. Control children brushed their teeth unassisted more often than the intervention children (p < 0.05). The intervention fathers also received more energy (in E%) from carbohydrates (p < 0.01), the intervention mothers used less fat (p < 0.05) and had a higher PUFA/SAFA ratio in the diet (p < 0.05) than the control fathers and mothers, respectively. Dental and periodontal health of the intervention and control parents (n = 250, 84% attending, mean +/- SD age: 34.2 +/- 54.5 years also showed no differences even though the control parents had more commonly last visited a dentist over 3 years before this examination (p < 0.05). We conclude that a 29-month period of a low-saturated-fat, low-cholesterol but high-carbohydrate diet as advocated in the STRIP baby trial does not seem to have harmful effects on the oral health of the children or their parents. Minor untoward differences had occurred in the dental health behavior of the control children and their parents.