Enamel Defects

Abstract

Developmental defects of enamel (DDE) affect a significant proportion of the population, with the possibility of defects in both primary and permanent dentitions. Two major defect types exist – hypoplasia and hypomineralisation (demarcated and diffuse lesions); and they can be hereditary (genetic) or acquired. The type of acquired defect depends on the timing of the aetiological factor’s influence on the ameloblast – if it is during the secretion or transition phases of amelogenesis, then hypoplasia is more likely. Later, during the maturation phase, a hypomineralised defect is more likely.

Amelogenesis imperfecta is a hereditary condition with several phenotypes including hypoplastic and hypomineralised (hypocalcified and hypomature), with a prevalence ranging from 1 in 700 to 1 in 14,000, depending on the population. Molar–incisor hypomineralisation (MIH) is a more recently recognised and defined acquired condition affecting permanent first molars and often incisors, which is likely to also have some genetic influences. The average worldwide prevalence of MIH is approximately 14%, with a huge range from close to zero to over 40%. At present, the aetiological factors are unknown, apart from a higher incidence amongst individuals who had infantile and childhood illnesses. All teeth in the primary and permanent dentitions can be affected with similar MIH-like demarcated lesions.

Several indices are used for classification and quantification of DDE – unfortunately, often this diversity leads to poor comparability between studies; however, more recently, the mDDE index and the European Academy of Paediatric Dentistry (EAPD) MIH index have become predominant.

Overall, DDE show high prevalence. Early and correct diagnosis will aid correct treatment planning, improve the prognosis of affected teeth and maximise health outcomes in the affected individuals.