【名词&注释】
肝肾阴虚(liver-kidney yin deficiency)、酸中毒(acidosis)、乳牙根尖周炎(periapical periodontitis primary teeth)、症状不明显(symptoms was not obvious)、牙龈上皮(gingival epithelium)、髓室底(pulp floor)
[单选题]乳牙根尖周炎常出现瘘管的原因是
A. 儿童患龋率高,症状不明显
B. 患儿不易合作,治疗不彻底
C. 乳牙根分歧大,髓室底(pulp floor)薄
D. 病变进展快和牙槽骨疏松
E. 牙龈上皮(gingival epithelium)薄,角化差,固有层疏松