American Board of Orthodontics (ABO) Practice Exam 2026 - Free Orthodontics Practice Questions and Study Guide

Patients with a low SN-MP angle typically exhibit a skeletal pattern associated with a more horizontal orientation of the mandibular plane relative to the spheno-nasal (SN) plane. This orientation can lead to certain alveolar characteristics. A thinner mandibular alveolus is often observed in these patients due to the reduced vertical growth and differences in the position of the teeth within the alveolar bone. The structural adaptations in response to the low-angle profile can result in less bone density and width around the lower arch, particularly affecting the mandibular alveolus.

In contrast, the broader maxillary alveolus and thicker alveolus around molars are features that might be associated with different skeletal patterns or dental relationships, while a normal alveolar structure suggests typical growth patterns not specifically tied to the low SN-MP angle. Therefore, the most accurate characteristic of low SN-MP patients in relation to the alveolus is the presence of a thinner mandibular alveolus.