Background: Dental caries and enamel defects are the main causes of poor dental health in children, with a substantial impact on their well-being. Use of inhaled asthma medication is a suspected risk factor, but there is a lack of prospective studies investigating this and other prenatal and early life risk factors. Methods: Copenhagen Prospective Studies on Asthma in Childhood 2010 mother–child cohort (COPSAC₂₀₁₀) consists of 700 women who were recruited at 24 weeks of pregnancy. 588 of their children participated in a dental examination at 6 years of age (84%) at the COPSAC₂₀₁₀ research unit. Caries was defined as decayed, missing, or filled surfaces. Enamel defect was defined as demarcated opacity, post-eruptive enamel breakdown, and/or atypical restoration on at least one molar. Caries and enamel defects were assessed in both deciduous and permanent dentitions. Results: We found no associations between inhaled corticosteroids or β₂-agonists or asthma symptoms in early childhood and the risk of caries or enamel defects by 6 years of age. Furthermore, we found no strong pre-, peri-, or postnatal risk factors for dental diseases at 6 years, except from nominally significant associations between antibiotic use in pregnancy (OR = 1.25, [1.01–1.54]), maternal education level (OR = 1.57, [1.01–2.45]), having a dog at home (OR = 0.50, [0.27–0.93]), and risk of enamel defects. Conclusions: Use of inhaled corticosteroids, β₂-agonists, or asthma symptoms in the first 6 years of life were not associated with the development of caries or enamel defects. This finding is reassuring for parents and physicians prescribing asthma medication for young children.