In the described occlusion, the MB cusp of the mandibular first molar occludes in the embrasure area between the maxillary second premolar and first molar. This corresponds to which Angle classification?

• A. Angle Class I
• B. Angle Class II
• C. Angle Class III
• D. End-to-End

Answer: (A)

In Angle’s system, the posterior molar relationship is defined by where the mesiobuccal cusp of the upper first molar sits relative to the lower teeth (or, equivalently, where the lower first molar cusp lies in relation to the upper teeth). When the mesio-buccal cusp of the mandibular first molar occludes in the embrasure between the maxillary second premolar and first molar, this reflects a normal, neutral posterior relationship without an anterior-posterior shift. It shows a balanced bite rather than the distal pull seen in Class II or the mesial shift seen in Class III, and it is not cusp-to-cusp contact as seen in end-to-end scenarios. Therefore, this arrangement corresponds to Angle Class I occlusion.