患者，男，40岁。<img height="20" src="/Image1/0e/0e874be728af6644a3204b6c3b27c11f.jpg" style="width: 25px; height: 14px;" width="32" />缺失，3年前行<img height="21" src="/Image1/8d/8d27c9ef49c5caae8ce20c96f19560eb.jpg" style="width: 18px; height: 17px;" width="22" />全冠固位体固定义齿修复，现基牙<img height="20" src="/Image1/d6/d65037b1f3381b1c1ca932fe89d7aca8.jpg" style="width: 17px; height: 15px;" width="18" />松动。基牙松动的原因是（）。<br>A:<img src="/Image1/29/29622c934116b49c3e077dbc3398ff10.jpg" />力过大<br>B:固位力不等<br>C:<img src="/Image1/29/29622c934116b49c3e077dbc3398ff10.jpg" />力不平衡<br>D:固位体选择不当<br>E:固位体边缘不密合