17. 下列何種齲齒不是牙釉質表面開口很小的穿通性齲齒常發生之型態?(A) 齒頸部齲齒(cervical caries)(B) 凹點或溝裂齲齒(pit and fissure caries)(C) 鄰接面齲齒(proximal caries)(D) 急性齲齒(acute dental caries)