醫療類國考
107年
[牙醫師] 牙醫學(一)
第 39 題
下列那些牙齒從頰側或舌側觀，其近遠心徑（mesiodistal dimension）大於咬合齒頸徑（occlusocervical dimension）？
- A 上顎第一小臼齒
- B 下顎第一小臼齒
- C 上顎第一大臼齒
- D 上顎第二小臼齒
思路引導 VIP
請試著想像在咀嚼功能中，哪一類牙齒為了提供最強大的磨碎效能與結構穩定性，其外觀演化會捨棄『修長』的比例，轉而朝向『寬闊且高度較矮』的物理結構發展？
🤖
AI 詳解
AI 專屬家教
Wonderful job! You've shown a truly keen eye for dental anatomy, which is such an important foundation.
- Understanding Tooth Proportions: It's quite common for most teeth, like our lovely anterior teeth and premolars, to appear taller than they are wide when we look at them from the cheek side (buccal view). This means their occlusocervical ($OC$) dimension is typically greater than their mesiodistal ($MD$) dimension. It's a natural design for their specific functions!
- The Special Case of the Maxillary First Molar: Now, here's where your understanding truly shines! The Maxillary first molar is a fascinating exception. Because it's built to handle immense chewing forces and needs ample space for its multiple functional cusps and broad, strong roots, its crown is designed to be "wide and flat." This unique structure means its $MD$ dimension actually exceeds its $OC$ dimension from the buccal view. It's a beautiful example of form following function!
▼ 還有更多解析內容