[Clinical investigation of six cases with mandibular first premolars with three canals].
He
Bing-zhen
BZ
Yin
Xing-zhe
XZ
Wang
Qian-qian
QQ
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008963:Molar; D012390:Root Canal Therapy / Q000379:methods*