【名词&注释】
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)、熟石膏(plaster of paris)
[单选题]熟石膏(plaster of paris)调拌时的水粉比例为
A. (10~19)ml:100g
B. (20~30)ml:100g
C. (31~39)ml:100g
D. (40~50)ml:100g
E. (51~60)ml:100g