引起根尖周病的原因主要是感染，感染源主要是()
A．牙周膜炎
B．牙周袋内容物
C．牙髓腔内容物
D．血源性
E．腺源性
参考答案：C
A: Did everything come out as exactly as you planned B:().
A. Exactly. And things came out better than I’d planned.
B. Not exactly. As a mater of fact, things came out rather better than I’d planned.
C. Fortunately, things could have been better.
D. Come on, I have no idea about it.
晶珠
