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Fig. 1.8 Dilaceration, buccal-palatal, of an upper central incisor due to trauma in the predecessor primary tooth
Dens Invaginatus (Dens in Dente)
Definition
• Refers to a defect characterized by a prominent lingual cusp and a centrally located pit (Fig. 1.9).
Etiology
• The defect results from early invagination of the enamel epithelium into the dental papilla of the underlying tooth germ. Local and genetic factors have been implicated.
Occurrence in children
• Rare in primary teeth.
• More common in permanent teeth (1–5%).
Localization
• Upper permanent lateral incisors, usually bilateral.
Clinical features
• The defect may not be clinically apparent, and does not frequently cause problems. If present, the labial surface of the tooth is normal, whereas the defect in the lingual surface may vary from a deep cingulum pit to a tooth with grossly distorted crown and root.
• Three types of the defect are recognized, depending on the extension of the cavity into the root.
Complications
• Increased frequency of caries in the lingual pits of the affected teeth due to the thin and incomplete layer of enamel, followed occasionally by pulp inflammation and necrosis, as a result of improper brushing and cleaning of the involved area.
Treatment
• Preventive filling of the pit. In case of odontogenic infection, endodontic treatment of the tooth.
Dens Evaginatus
Definition
• Refers to a defect characterized by an elevated, tuberculated appearance of the occlusal surface of the affected teeth. Evaginations contain enamel, dentine, and pulp (Fig. 1.10).
Etiology
• The defect results from focal hyperplasia of the ectomesenchyme of the primitive dental papilla. Genetic factors acting during the developmental period of the teeth have been implicated.
Occurrence in children
• Rare (less than 1%).
• Frequent finding in individuals of Mongolian origin (1–4%).
Localization
• Premolars and molars, usually bilaterally.
Clinical features
• The affected teeth have a conical, tuberculated projection from the central fissure of the occlusal surface.
Complications
• Pulp may extend into the tubercula, resulting in an increased risk of pulp exposure after mild mechanical trauma to the occlusal surface.
Treatment
• Reduction of the occlusal tubercula (cusp) in order to induce formation of secondary dentine, or reduction of the opposing tooth in order to eliminate possible traumatic occlusion.
Taurodontism
Definition
• Refers to a dental defect usually found in multirooted teeth. It is characterized by a prolonged crown and more apically located root furcation, resulting in the creation of enlarged pulpal chambers with increased occlusal-apical length (Fig. 1.11). Three types of the defect have been recognized, termed hypotaurodontism, mesotaurodontism, and hypertaurodontism according to the extension of the pulp chamber into the root.
• The defect has also been classified among pulp dysplasias.
Etiology
• Polygenic, with additional implication of local factors. The defect has been attributed to the failure of the Hertwig’s epithelial root sheath to invaginate below the crown at the proper time during dental development.
• Taurodontism is frequently found in patients with trisomy 21 and Klinefelter syndromes, as well as other chromosomal anomalies involving an abnormal number of X chromosomes.
• It is also found in cases of type IV amelogenesis imperfecta, trichodento-osseous syndrome types I, II, III, Down’s syndrome, ectodermal dysplasia, and some other syndromes.
Occurrence in children
• Rare in primary teeth.
• More common in permanent molars (6–10%).
Localization
• First and second molars.
• Frequently a bilateral finding.
Clinical features
• Definite diagnosis only with radiographs revealing vertical enlargement of the coronal pulp chamber extending below the cervical area of the tooth. The bifurcation or the trifurcation of the root is displaced apically.
Complications
• Needs special care in case of endodontic treatment.
Treatment
• No treatment is required, since the affected teeth are asymptomatic.
Fig. 1.9 Dens in dente (dens invaginatus) of an upper central incisor, resulting in pulpal necrosis
Fig. 1.10 Dens evaginatus in an upper molar
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