Thumb-sucking associated anterior open bite — ORE Part 1 MCQ

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ModerateOrthodonticsThumb-sucking associated anterior open biteORE Part 1

A 7-year-old has an anterior open bite, proclined maxillary incisors and a posterior crossbite. The parent reports persistent thumb sucking at night. The child is otherwise healthy and has normal nasal breathing. What is the most likely cause of this occlusal pattern?

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Correct answer: C — Persistent thumb-sucking habit

The correct answer is C. Persistent digit sucking produces characteristic dentoalveolar change: pressure from the digit can procline the maxillary incisors and impair anterior alveolar vertical development, causing an anterior open bite. It is also associated with posterior crossbite. Thus, the history accounts for the complete occlusal pattern. Congenital absence of incisors causes a tooth-number discrepancy rather than this combination of incisor inclination and transverse malocclusion. Ankylosis produces localised infraocclusion and eruption disturbance. Fluorosis is a developmental enamel defect and does not alter occlusion. Acute apical infection is a local inflammatory condition and cannot explain a chronic multi-region malocclusion.

Reference: Warren JJ, Bishara SE. Artificial sucking habits: etiology, prevalence and effect on occlusion. Journal of the American Dental Association, 1998. https://pubmed.ncbi.nlm.nih.gov/9055659/