Hypocalcification
• Regular enamel thickness at the time of tooth eruption.
• Soft enamel easily removed.
• Gradual reduction of the thickness resulting from easy attrition.
• Only dentine remains in severe forms of the defect.
• Increased sensitivity in thermal stimuli.
• Yellow-brownish color of the enamel, with pigment deposition.
• Associated occasionally with anterior skeletal open-bite.
Hypomaturation
• Opaque mottled enamel of normal thickness.
• Enamel approaches the radiodensity of dentine.
• Relatively soft enamel with frequent microfractures.
• Mottled brownish-yellow to white appearance.
Complications
• Occasional occlusal distortion, aesthetic problems, sensitivity.
Treatment
• Conservative aesthetic restorations; in severe cases, prosthetic rehabilitation.
Fig. 1.30 Enamel hypoplasia and hypomineralization of an upper central incisor, resulting from surgical intervention in the area when the patient was aged two
Fig. 1.31 Enamel hypomineralization and hypomaturation of an upper premolar, resulting from chronic pulpal infection of the predecessor primary molar
Fig. 1.32 Hypomineralization and hypomaturation (opacities) of the permanent incisors and molars, resulting from prolonged use of antibiotics for chronic infection in the neonate
Fig. 1.33 Hypoplastic pitted amelogenesis imperfecta (type Ia)
Fig. 1.34 Hypoplastic amelogenesis imperfecta with local hypoplasias (type Ib)
Fig. 1.35 Hypoplastic amelogenesis imperfecta with smooth enamel (type Id)
Fig. 1.36 Hypoplastic amelogenesis imperfecta with rough enamel (type If)
Fig. 1.37 Hypomature amelogenesis imperfecta (type IIb)
Fig. 1.38 Hypomineralized amelogenesis imperfecta. Autosomal fominant (type IIa)
Enamel Defects Associated with Genetic Disorders
Definition
• Many genetic disorders or syndromes may be associated, with variable incidences, with a wide variety of enamel defects. In these cases, the defect is not termed "amelogenesis imperfecta" but "enamel hypoplasia," "enamel hypocalcification," or "enamel hypomaturation," depending on the clinical features of the defects (Figs. 1.40, 1.41).
Genetic disorders
• Tricho-odonto-onychial dysplasia
• Oculodentodigital syndrome, types I and II
• Orofaciodigital syndrome (type I)
• Amelo-onychohypohidrotic dysplasia
• Ectodermal dysplasia with syndactyly
• Amelocerebrohypohidrotic syndrome
• Acrorenal ectodermal dysplasia, lipoatrophic diabetes
• Enamel renal syndrome
• Epidermolysis bullosa, dystrophic
• Focal dermal hypoplasia (Goltz syndrome)
• Hypomelanosis of Ito
• Corneodermato-osseous syndrome
• Naegeli–Franceschetti–Jadassohn syndrome
• Trichodento-osseous syndrome (types I, II, III)
• Seckel’s syndrome
• Arthrogryposis and ectodermal dysplasia
• Prader–Willi syndrome
• Singleton–Merton syndrome
• Congenital insensitivity to pain with anhydrosis
• Faciogenital dysplasia (Aarskog’s syndrome)
• Mucopolysaccharidosis IV A, B (Morquio–Ullrich syndrome)
• Lipoid proteinosis
• Mucolipidosis II (Leroy I syndrome)
• Vitamin D–dependent rickets
• Pseudohypoparathyroidism (Albright hereditary osteodystrophy)
• Tuberous sclerosis
• Pycnodysostosis
Fig. 1.39 Hypomineralized amelogenesis imperfecta. Autosomal recessive (Type IIb)
Fig. 1.40 Enamel hypoplasia in a patient with Goltz syndrome
Fig. 1.41 Enamel hypoplasia in a patient with tuberous sclerosis
