Objective: The aims of this case-control study were to (a) compare the caries experience and oral hygiene, and (b) quantify the persistence of a delay in the dental age in children with cardiac disease and a group of healthy children. Methods and Materials: The study population comprised a group of 268 3- to 16-year-old children and adolescents with a cardiac disease and a group of 268 age- and sex-matched healthy children and adolescents. Specifically, the decayed, missed, and filled teeth indices, simplified oral hygiene index, and the dental ages of the two groups of children were calculated and then compared. Results: Although the oral health of the children with either a congenital or an acquired heart disease was the same as that of the healthy children, there were significant differences in the decayed, missed, and filled teeth indices. Dental ages of the children with a congenital heart disease were significantly lower than those of healthy children. The findings showed that complex univentricular heart diseases had the highest negative impact on dental development (-1.1), followed by complex biventricular (-0.9), simple surgical (-0.5), and mild (-0.4) heart disease patients. Conclusion: Once thorough knowledge of the child's cardiac status is gained, a definitive dental treatment plan for the child with a cardiac disease can be established.