Enamel defects

Date: 2015-10-07; view: 656.

Enamel defects may be caused by genetic or environmental factors, acting alone or in combination. Where less enamel matrix than normal is produced, the resulting enamel will be thinner (hypoplasia). If there is a defect in mineralization of the enamel matrix proteins, then the result will be poorly mineralized enamel (hypomineralization - sometimes subdivided into hypocalcification for more severe defects and hypomaturation for milder changes). In many cases there will be a combination of both hypoplasia and hypomineralization, although sometimes the defect will be perceived clinically as predominantly one or the other. When enamel hypoplasia is seen the enamel may be uniformly thin, or grooved or pitted. In hypomineralization the enamel will typically be discoloured, usually a yellow-brown colour. This is particularly expressed where the defect is severe (hypocalcification) whereas in a less severe presentation (hypomaturation) the enamel may be almost normal but appear mottled or even only slightly opaque rather than translucent.

“Environmentally determined” enamel defects

Enamel defects may arise as a result of an “environmental” injury. Within this sense we include both a systemic upset and a result of a local factor involving the developing tooth. Where there is a systemic injury the teeth will be affected in a chronological pattern, so that a band of abnormal enamel is seen in horizontal distribution at some part on the tooth crown. Typically this results in a groove in the enamel of affected teeth. The term chronological hypoplasia is often used to describe such cases. A knowledge of the timing of commencement of formation of the teeth will aid in understanding the timing of such an injury.