Comparative Anatomy — MCQs

Question 11: Dryopithecus pattern is the characteristic feature of:

• A. Permanent maxillary 2nd molar.
• B. Permanent mandibular 1st molar. (Correct Answer)
• C. Permanent mandibular 3rd molar.
• D. Permanent maxillary canine.

Explanation: ***Permanent mandibular 1st molar*** - The **Dryopithecus pattern**, also known as the **Y-5 configuration**, is a characteristic groove pattern found on the occlusal surface of the **permanent mandibular first molar**. - This pattern is formed by the arrangement of the major grooves that create a distinct "Y" shape with five cusps, where three grooves converge at a central point. *Permanent maxillary 2nd molar* - The permanent maxillary second molar typically exhibits a **cruciform** or **plus-pattern (+ pattern)** groove configuration on its occlusal surface, not the Dryopithecus pattern. - It often has **four cusps**, with the distolingual cusp sometimes reduced or absent. *Permanent mandibular 3rd molar* - While mandibular third molars can have variable cusp and groove patterns, the **Dryopithecus pattern** is not considered their characteristic feature. - They often have **anomalous occlusal morphology** and can present with various cusp numbers and groove arrangements due to evolutionary reduction. *Permanent maxillary canine* - Maxillary canines are **single-cusp teeth** with a pointed incisal edge and a cingulum on the palatal surface. - They lack an occlusal surface with cusps and grooves, therefore, the **Dryopithecus pattern is not applicable** to canines.