【評論主題】59.根管治療過的後牙，若齒質厚度足夠，且牙髓腔能提供冠心（core）足夠的固持力，則牙齦以上至少具有多少齒質高度時，就可不必放置根柱（post）？ (A)1.5 mm (B)3 mm (C)4.5

【評論內容】

來自課本 pg285

When morethan 3 to 4 mm of coronal tooth structure with reason-able wall thickness remains, use of a post in the rootcanals for retention is not necessary, and not having toprepare post space reduces the risk of perforation.