invagination of Hertwig's epithelial root sheath, lined with cementum. Dens invaginatus has a clinical importance as teeth affected with dens invaginatus are predisposed to developing pulpal disease. The invagination allows entry of irritants into an area which is separated from pulpal tissue by only a thin layer of enamel and dentine and extra preventative measures are advised to prevent dental caries. Enamel Defect and Coeliac Disease Coeliac disease in children is thought to be underdiagnosed because it may initially be asymptomatic. Studies have shown that enamel defect of permanent and deciduous or primary teeth may suggest the presence of undiagnosed coeliac disease in children and adults. Coeliac disease-related enamel defects are most commonly associated with incisors and first molar teeth, and are characterised by symmetrical distribution of enamel defects on the same tooth in all 4 quadrants. This is a distinct characteristic of enamel defects in coeliac disease that cannot be seen in other enamel defects. Enamel defects in coeliac disease occur due to an interference in tooth formation by amelogenin. Amelogenin is a proline-rich enamel protein that plays a major role in mineralisation and organisation of tooth crystals. Disruption to this process cause alterations in the tooth surface. Patients with coeliac disease produce high levels of circulating IgG and IgA antigliadin antibodies (AGA) in order to get rid of protein gliadin, which is toxic to these patients. However, due to the structural similarities between amelogenin and gliadin, AGA may interfere with amelogenin which lead to improper formation of enamel. Furthermore, because IgG can be transported across the placenta, the amelogenesis process is disturbed from the intrauterine period to adolescence. Gliadins are highly hydrophobic proteins in wheat gluten. The antibodies are produced to interact with this protein. Therefore, a gluten-free diet may lead to normalisation of tooth development as circulating antibodies for enamel defect may decrease. See also Ameloblast Tooth Tooth development Tooth enamel References Tooth development