Pathological Migration Mechanism — ORE Part 1 MCQ

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ModeratePeriodontologyPathological Migration MechanismORE Part 1

An adult reports that the upper anterior teeth have become spaced and flared during the past year. They have generalised advanced periodontal bone loss. There is no reported thumb-sucking, tongue-thrust habit or parafunction. Which mechanism most likely explains this pathological tooth migration?

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Correct answer: E — Normal occlusal forces acting on reduced periodontal support

Explanation lettering: D = shown as A · E = shown as C · C = shown as D · A = shown as E

A is correct. Advanced periodontal bone loss reduces the periodontium’s capacity to resist ordinary functional occlusal loading. The resulting displacement of teeth is secondary occlusal trauma and may present as pathological migration, spacing and flaring of upper incisors. B describes primary occlusal trauma: excessive forces acting on a periodontium with normal support, which is not the key finding here. C is inappropriate for an adult with recent movement and established severe periodontal destruction. Tongue thrust and thumb sucking can contribute to anterior displacement, but the stem excludes those habits and identifies the decisive cause: markedly reduced periodontal support. The question tests the distinction between abnormal force magnitude and a reduced ability of the supporting tissues to tolerate otherwise normal forces.

Reference: Stoenescu C, et al. Orthodontic Management of a Migrated Maxillary Central Incisor With a Secondary Occlusal Trauma. Case Reports in Dentistry, 2019. https://pubmed.ncbi.nlm.nih.gov/42178740/