imperfecta

Imperfecta is a term used to describe conditions characterized by abnormal formation or structure of a tissue. In dentistry, amelogenesis imperfecta (AI) is a group of inherited disorders affecting enamel formation. AI results from mutations in genes that encode enamel proteins or enzymes involved in mineralization, including AMELX (amelogenin X-linked), ENAM (enamelin), MMP20 (enamelysin), KLK4, WDR72, C4orf26, among others. Inheritance patterns may be X-linked dominant or autosomal dominant or autosomal recessive, depending on the gene.

Phenotypes of AI are classified by enamel defects: hypoplastic AI with thin enamel due to reduced enamel matrix; hypomaturation AI with normal thickness but soft or chalky enamel; hypomineralized AI with enamel of normal thickness but porous and poorly mineralized. Clinically affected teeth may appear discolored (cream, yellow, brown, or grey), with enamel loss leading to sensitivity and rapid wear, chipping, and esthetic issues. In radiographs, enamel may be reduced in thickness or absent.

Diagnosis combines clinical examination, radiography, and genetic testing; differential includes other conditions causing enamel defects or dentin defects. Management is multidisciplinary: preventive dental care, fluoride therapy, sealants, and restorations such as composite bonding, veneers, crowns, or full-coverage restorations, tailored to age and severity. Early detection improves function and aesthetics. The condition is rare, with prevalence varying by population and AI subtype; many patients require ongoing dental follow-up through adulthood.