American Board of Orthodontics (ABO) Practice Exam

A retrusive mandible, which refers to a mandible that is positioned further back in relation to the maxilla, often leads to specific dental compensations due to the relationship changes between the teeth and the bone structures. In this scenario, the upright positioning of maxillary incisors occurs as a compensatory mechanism to maintain occlusion and functional aesthetics. By being upright, the maxillary incisors can help in accommodating the positioning of the retrusive mandible, thereby providing better anterior guidance during functional movements such as biting and chewing.

Simultaneously, the lower incisors tend to flare anteriorly in this situation. This flaring is a response to the retruded position of the mandible, allowing for a more favorable contact relationship with the maxillary teeth and promoting proper alignment in the dental arch. The flared position of the lower incisors can help reduce the overbite that might occur with a retrusive mandible and facilitate occlusal function.

The other options present different relationships that do not align with the typical outcomes of a retrusive mandible, leading to their exclusion as correct answers in this context. Understanding these compensatory mechanisms is crucial for orthodontic treatment planning and predicting how malocclusions may influence tooth positioning.