An uncorrected anterior open bite with a tongue thrust habit can lead to an adverse consequence in the dental alveolar complex via a mechanism of:

 # An uncorrected anterior open bite with a tongue thrust habit can lead to an adverse consequence in the dental alveolar complex via a mechanism of:

A. Disruption of the equilibrium between tongue and lip muscle forces

B. Increased risk of periodontal bone loss due to heavy occlusal forces

C. Pathologic attrition of the posterior teeth

D. Skeletal mandibular retrusion

The correct answer is A. Disruption of the equilibrium between tongue and lip muscle forces

In uncorrected anterior open bite with tongue thrust, the aberrant lingual pressure during deglutition and speech exerts a supracrestal force (20–50 N) on the lingual inclines of maxillary and mandibular incisors, overriding the restraining orbicularis oris and mentalis tonicity—resulting in progressive labial flaring, anterior spacing, and failure of spontaneous closure, with alveolar bone remodeling adapting to this disequilibrium (e.g., reduced interradicular bone density via osteoclast activation). This perioral imbalance is the core mechanism for perpetuating the malocclusion in the dental alveolar complex, as confirmed by electromyographic and cephalometric studies showing 70–80% of persistent open bites linked to such habits. Option B misattributes bone loss to occlusal overload (actually reduced anteriorly); C involves posterior supraocclusion but not primary attrition; D relates more to vertical growth patterns than functional thrust.