A radiograph of a 10-year-old shows permanent central incisors with wide root canals and thin dentinal walls. What is the diagnosis?

Correct answer: C. Normal anatomy for the stage of root development

• A. Internal resorption produces a localised, balloon-like OVAL expansion of the canal, not a uniformly wide canal with an open apex, and it is a pathological process usually following trauma or pulpitis.
• B. Taurodontism is an enlarged pulse CHAMBER with apical displacement of the furcation, affecting MULTIROOTED teeth. It cannot occur in a single-rooted incisor.
• C. CORRECT. This is NORMAL. Root formation continues for roughly three years after eruption, so a permanent incisor in a 10-year-old still has a wide, divergent canal, thin dentinal walls and an incompletely closed apex. Apical closure of the maxillary central incisor occurs at about 10–11 years. Recognising this as normal matters — it is why apexification or regenerative endodontics, rather than conventional obturation, is required if such a tooth becomes necrotic.
• D. Dentinogenesis imperfecta produces the opposite radiographic picture: OBLITERATED pulp chambers and canals, bulbous crowns, cervical constriction and short thin roots, with opalescent brown-blue crowns clinically.

Note: Root development timing: the crown completes, the tooth erupts, and the root takes about three more years to finish. A useful check when reading a paediatric radiograph — compare the tooth in question with its contralateral partner. A unilateral finding is pathology; a symmetrical one is almost always development.