According to the National Institute of Dental and Craniofacial Research, Down syndrome and other genetic disorders can cause delays in tooth eruption, sometimes up to two years. These children may also develop malformed or extra teeth that erupt or even have congenitally missing teeth. Crowding and poor alignment, in general, can leave children prone to gum disease and tooth decay because it makes their teeth difficult to keep clean. In cases of severe intellectual disability or cerebral palsy, children may also habitually grind their teeth, making them flat as they gradually break down the enamel.
Tooth decay and gum disease can also result from a child's impaired immune system and connective tissue disorders. Many of the medications your child may be taking could contain sugar or lead to dry mouth as a side effect, which is especially conducive to tooth decay. Certain medications can also cause an overgrowth of the gum tissue, so be sure to ask your doctor and dentist about the side effects of the medication your child may be taking.