What is the best definition of occlusal?

The term "occlusal" refers specifically to the chewing surface of the teeth, particularly the surfaces of the posterior teeth (molars and premolars) that come in contact with those of the opposite arch during biting and chewing. This definition reflects the functional aspect of these tooth surfaces as they play a critical role in the mechanics of mastication.

In dental terminology, the occlusal surface is also involved in the overall occlusion of the dentition, which includes how upper and lower teeth fit together. Therefore, when considering the options available, the best definition for "occlusal" effectively describes this function of the teeth where they are engaged in the process of chewing food.

The other options focus on different aspects of tooth surfaces—some describe relationships to other tooth surfaces or locations in the mouth that are not primarily concerned with the act of chewing. Therefore, the definition emphasizing the chewing surface accurately captures the essence of what "occlusal" means in a dental context.