American Board of Orthodontics (ABO) Practice Exam 2026 – All-in-One Resource to Master Your Orthodontics Certification!

The thickness of cortical bone is influenced by the functional load placed on specific teeth during occlusion and mastication. The distal buccal (DB) cusp of the second molar experiences significant forces during chewing, especially since the second molar is a key tooth involved in occlusal function and transferring forces during biting and grinding. This increased functional stress leads to greater bone density and thickness in that area to support the tooth's roots effectively.

Understanding this, the answer highlights the importance of occlusal forces in guiding the development of surrounding structures, such as cortical bone. The other options, while also related to molars, do not experience the same degree of occlusal stress that the DB cusp of the second molar does, leading to comparatively reduced cortical bone thickness in those locations.