Which permanent tooth most characteristically presents with THREE cusps?

Correct answer: D. The maxillary third molar

• A. The mandibular second premolar most often has THREE cusps in its three-cusp (Y-shaped) variant — one buccal and two lingual — but it also commonly occurs in a two-cusp (H- or U-shaped) form, so it is not the most characteristic answer here. The maxillary third molar is the classic tricuspid tooth.
• B. Maxillary premolars characteristically have TWO cusps, one buccal and one lingual, with the first premolar's buccal cusp the longer.
• C. The maxillary first molar characteristically has FOUR cusps plus the cusp of Carabelli, and is the most stable molar in form.
• D. CORRECT. The MAXILLARY THIRD MOLAR is the most variable tooth in the mouth and its commonest form is a heart-shaped, tricuspid crown: mesiobuccal, distobuccal and mesiolingual cusps, with the distolingual cusp absent or vestigial. Its root form is often fused and conical to match.

Note: ⚑ Worth discussing in the group: the mandibular second premolar's three-cusp form is a legitimate alternative answer, and some references key it that way. The maxillary third molar remains the classic tricuspid tooth on board examinations because its reduced distolingual cusp is a defining feature.