【評論主題】16.關於混合齒列牙齒發育問題的敘述，下列何者錯誤？(A)牙齒萌出不對稱，其定義為兩側萌出時間差異大於6個月 (B)除智齒外，恆牙缺失最常見於上顎側門牙及下顎第二小臼齒 (C)多生牙常發生於上顎前牙區

【評論內容】Cleidocranial dysplasia : Delayed eruption of primary teeth, delayed appearance of secondary teeth, supernumerary teeth, sometimes accompanied by cysts in the gums.