860H
Fig. 13.35 Disturbed
dental development,
fluorotic mottling:pre-
and post-microabrasion.861H
Fig. 13.36 Disturbed
dental
development⎯previous
primary tooth injury.13.7.3 Dentine defects
As with enamel defects, dentine defects may be of genetic origin or caused by
environmental effects.
Genetically determined dentine defects
DENTINOGENESIS IMPERFECTA
Dentinogenesis imperfecta is an autosomal dominant inherited condition. It may occur
in isolation or in association with osteogenesis imperfecta. This represents two
conditions, rather than a spectrum of effect. The term hereditary opalescent dentine is
sometimes applied because of the typical opalescent hue of the teeth.
Dentinogenesis imperfecta, both the typical variant and the 'Brandywine isolate'
variant in the eastern United States, has been mapped to chromosome 4 and the DSPP
gene has been shown to be mutated in several families (some of whom also have had
hearing defects). In some of the Brandywine isolate families, occasional individuals
have teeth which are indistinguishable from the more typical form of dentinogenesis
imperfecta; it is therefore likely that this represents an allelic variant of the same
genetic condition.
Similarly, the diagnosis of coronal dentinal dysplasia has been proposed but this also
seems likely to be a variant of dentinogenesis imperfecta.
Dentinogenesis imperfecta occurring in association with osteogenesis imperfecta is a
result of mutations in one of the two collagen type 1 genes on chromosome 7 or 17.
The dentine defects may be very apparent or rather subtle, in some cases requiring