Developmental Disorders
Developmental disorders involve teeth and the craniofacial structures. A few of these disorders are congenital diseases of the enamel or dentin; problems related to the number, size, or shape of teeth; and craniofacial birth defects, such as cleft lip and palate (CL/P). Among the most common congenital malformations seen in humans, cardiovascular malformation is ranked as the first and CL/P as the second. Unilateral CL/P occurs six times more frequently than the bilateral form. Females are more prone to get cleft palates, whereas cleft lip or CL/P is most common in males (U.S. Public Health Service 2000).
The incidence of CL/P differs from 0.18 to 3.74 per 1,000 live births, the highest incidence being seen in Native Americans at 3.74 per 1,000, closely followed by the Japanese at 3.36 per 1,000 live births. A fairly uniform incidence of 1 per 600 to 700 live births is reported among Europeans. Overall, the incidence rates appear high among Asians (0.82 to 3.36 per 1,000 live births), intermediate in Caucasians (0.9 to 2.69 per 1,000 live births), and often very low in black Africans (0.18 to 1.67 per 1,000 live births) (Hewson and McNamara 2000; Vanderas 1987; Wantia and Rettinger 2002).
The causes of CL/P are complex, involving multiple genetic and environmental risk factors. Not all cases of CL/P are inherited. A number of risk factors, such as folic acid deficiencies, maternal smoking, and maternal age, have been implicated in the formation of clefts (Wantia and Rettinger 2002).
Advanced surgery, specific prosthetic appliances, and orthodontic treatment can improve the quality of life for those born with clefts. However, such treatment is not accessible to children of several developing countries. Tobacco cessation programs aimed at pregnant mothers are essential in the prevention of CL/P.
