Occurrence of developmental morphological defects in permanent teeth of mentally retarded children

A group of 9- to 11-year-old mentally retarded children (n = 92) and randomly selected healthy controls of the same age (n = 67) were psychologically tested for mental performance and examined for developmental morphological defects in their permanent teeth. About twice as many teeth with developmental defects in crown morphology were found in the retarded children as in healthy children. In retarded children, the frequency of defective dental crowns increased with the severity of mental retardation, as measured in terms of IQ. Owing to modifying factors that affect IQ, however, this trend can be questioned.