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Dahl Appliance Outcome — ORE Part 1 MCQ

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HardRestorative DentistryDahl Appliance OutcomeORE Part 1

A patient has a deep overbite with palatal wear of the maxillary incisors caused by the mandibular incisor edges. A removable Dahl appliance is fitted to create restorative space anteriorly. What is the most likely occlusal outcome after 4–6 months?

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Correct answer: B — Posterior contacts re-establish through anterior intrusion and posterior eruption

**A is correct.** A Dahl appliance is an anterior bite platform that initially discludes the posterior teeth. In most patients, the posterior open bite resolves over about 4–6 months by relative axial tooth movement: anterior intrusion contributes about 40% and posterior compensatory eruption about 60%. Thus posterior contacts re-establish while restorative space is maintained anteriorly. **B** is wrong because posterior disclusion is usually temporary. **C** is wrong because the movements are not equivalent and the posterior teeth erupt rather than intrude. **D** is incomplete: anterior intrusion alone does not explain the usual response. **E** is wrong because re-establishment of occlusion results from altered dentoalveolar tooth positions, not return to the original untreated relationship.

Reference: Faculty of Dental Surgery, Royal College of Surgeons of England. Clinical guidelines for dental erosion, section “Palatal wear of maxillary incisors”, 2021. https://www.rcseng.ac.uk/-/media/Files/RCS/FDS/Guidelines/Erosion-Guidelines_2021_V4_MJ.pdf