ProTaper Universal nickel titanium rotary file
versus
stainless-steel hand file: the security for root canal preparation
Yao Xi, Li Hong-mei, Li Yun-sheng, Dai Yong-yu
Chinese Journal of Tissue Engineering Research . 2015, (
8
): 1250 -1254 . DOI: 10.3969/j.issn.2095-4344.2015.08.019