Genetic disorders, syndromes
• Hypophosphatasia
• Osteogenesis imperfecta types I, III, IV (dentinogenesis imperfecta type I)
• Unger–Trott syndrome
• Vitamin D–resistant rickets
• De Toni–Debré–Fanconi syndrome
• Albright hereditary osteodystrophy (pseudohypoparathyroidism)
• Mucopolysaccharidosis III (Sanfilippo syndrome)
• Tumoral calcinosis
• Ehlers–Danlos syndrome
• Epidermal nevus syndrome
• Brachioskeletogenital (BSG)syndrome
• Dentine–osseous dysplasia
Fig. 1.46 Radiological features of radicular dentine dysplasia (type I)
Fig. 1.47 Radiological features of coronal dentine dysplasia (type II)
Defects Involving the Whole Tooth Structure
Odontodysplasia
Definition
• The term refers to a severe dental defect involving all dental tissues of both ectodermal and mesodermal origin.
Etiology
• The etiology is still unknown, although local, systemic, and genetic factors have been implicated. Recently, reports have suggested that the defect is caused by local vascular deficiency, resulting from a local developmental anatomic defect, such as a vascular nevus.
• The alteration has occasionally been associated with the epidermal nevus syndrome.
Occurrence in children
• Rare, but underreported.
• More common in females.
Localization
• Both primary and permanent dentitions are affected.
• Maxilla more frequently affected than mandible (2:1).
• The whole or part of a quadrant is involved. The defect crosses the midline in only 16% of the cases, affecting also anterior teeth.
Clinical features
• Tooth eruption is delayed and painful. Occasionally, teeth fail to erupt (Fig. 1.48).
• Frequent abscesses.
• Gingival enlargement and inflammation.
• Discolored yellow teeth with rough and small crowns and gross hypoplastic and hypocalcified enamel and dentine.
Radiological features
• Ghost-like appearance of the teeth with periapical radiolucencies (Fig. 1.49).
• Short roots with very wide pulp canals and open apices.
Complications
• Occlusal distortion, painful teeth, abscesses.
Treatment
• In cases of less affected teeth, prosthetic restoration. In severe cases, removal of the affected teeth and prosthetic rehabilitation of the involved area.
Tooth Discoloration
Definition
• Refers to color changes in the teeth.
Etiology
• The defects result from the deposition of various pigmented elements either on the enamel surface (extrinsic pigmentation) or in the inner layers of the dentine and pulp (intrinsic pigmentation).
• These defects are associated either with systemic factors and involve all the teeth, or with local factors, mainly trauma, involving certain teeth (Fig. 1.50).
Occurrence in children
• Rare.
Clinical features
Extrinsic pigments may involve all or some of the teeth, and result from an excess of various chemical elements in the saliva, which may or may not be metals, including the following (Fig. 1.51):
• Iron, magnesium, silver: black pigmentation.
• Mercury: gray or green-black pigmentation.
• Lead: gray pigmentation.
• Copper: brown or green pigmentation.
• Bromides: brown pigmentation.
• Nickel, antimony: green pigmentation.
• Cadmium: yellow pigmentation.
• Potassium: violet pigmentation.
• Enamel hypoplasia/hypocalcification: yellow-brown pigmentation.
Intrinsic pigments. This group includes the following, apart from local discoloration due to trauma:
• Erythroblastosis fetalis (incorporation of bilirubin into the developing dentition): yellow-green and blue-green color of teeth, gradually reducing with age; particularly noticeable in the anterior teeth.
• Tetracyclines (incorporation of tetracycline into the hydroxyapatite of the calcified areas of the dentine and in smaller amounts in the enamel): initially light yellow, and later a darker gray-brown color in the teeth, with horizontal bands.
• Erythropoietic porphyria, congenital (incorporation of porphyrin in developing dentition): reddish-brown or pinkish discoloration of the teeth.
• Alcaptonuria (deposition of homogentisic acid in the developing dentition): brown color of the teeth.
• Oxalosis (incorporation of oxalate crystals into the developing dentition): slate-gray discoloration of
