Genetic Etiology Of Development Alterations Affecting The Number, Size, Form, Structure And Eruption Of The Teeth

Abstract

Teeth develop in the mammalian embryo via a series of interactions between the odontogenic epithelium and the neural crest-derived ectomesenchyme of the early jaw primordia. The molecular interactions required to generate a tooth are mediated by families of signaling molecules, which often act reiteratively in both a temporal and spatial manner. In humans, the process of odontogenesis lasts approximately 18 years, beginning in the 6th-8th week in the uterus and ending with the formation of the third molars in late adolescence. Each tooth passes through a series of stages that follow the same pattern, beginning with the formation of the bud, then cap and bell, followed by the deposit of enamel and dentin on the crown of the tooth. After the crown is formed, the development of the roots continues and finally the teeth emerge in the oral cavity, when about 2/3 of the roots have formed. Alterations in the indicated processes lead to a wide range of abnormalities that affect the number, size, shape of teeth and structural defects in mineralized tissues, as well as failures in dental eruption. The prevalence of these disorders may be as common as 2, 4% in hypodontia or extremely rare as 1 in 100,000 in dentin dysplasia. The spectrum of these anomalies, which may occur in isolation or as part of syndromes is variable; being very mild to severe and very severe. Most of A 2