In which occlusion does the mb cusp of maxillary first molar contact distally to the mb groove of the opposing mandibular first molar?

In Class III Occlusion, the mesial-buccal cusp of the maxillary first molar contacts distally to the mesial-buccal groove of the opposing mandibular first molar. This positioning occurs due to the relationship of the maxillary and mandibular teeth when the maxilla is positioned posteriorly in relation to the mandible, resulting in a prognathic appearance.

In this type of occlusion, the overall alignment of the dental arches causes the maxillary molars to be positioned further back relative to the opposing mandibular molars. This is opposed to Class I, where the cusp contacts are typically in an ideal position, and Class II, where the maxillary molars are positioned more forward relative to the mandibular molars. Thus, Class III Occlusion specifically reflects this unique cusp-to-groove relationship.