A radiograph of a 10-year-old shows unusually WIDE root canals with large pulp chambers in the permanent central incisors. What is the diagnosis?

Correct answer: C. Normal anatomy for the patient's stage of development

• A. TAURODONTISM is defined by an apically displaced furcation with an elongated pulp chamber — a MULTI-ROOTED tooth phenomenon by definition. It cannot apply to single-rooted incisors.
• B. INTERNAL RESORPTION is a LOCALISED, balloon-like radiolucent expansion of the canal in a single tooth, usually after trauma or pulpal inflammation — not a symmetrical widening of both centrals.
• C. CORRECT. This is NORMAL. Permanent incisors erupt with OPEN APICES and wide, divergent canals; root formation is completed only about THREE YEARS AFTER ERUPTION. Since the permanent central incisors erupt around ages 7 to 8, a 10-year-old is still within the normal window of root maturation, with canals that taper little and apices that may still be blunderbuss in shape. Secondary dentine deposition then progressively narrows the canal throughout life.
• D. DENTINOGENESIS IMPERFECTA produces the OPPOSITE radiographic picture: OBLITERATED pulp chambers and canals, bulbous crowns with cervical constriction, short thin roots, and blue-grey opalescent teeth with enamel that fractures away.

Note: Clinically decisive: an immature tooth with an open apex that needs endodontic treatment gets APEXOGENESIS if the pulp is vital, or APEXIFICATION or a regenerative procedure if it is necrotic. Conventional obturation is not possible without an apical stop.