Sun C, et al. - In this meta-analysis authors compared the incidence and intensity of postoperative pain following single-visit root canal treatment using manual, rotary and reciprocating instruments. They noted that compared to the use of hand files in subjects who received single-visit root canal treatment, the use of rotary instruments contributed to a lower incidence and intensity of postoperative pain. Furthermore, the use of multiple rotary-file systems led to a decreased incidence of the postoperative pain compared to the use of reciprocating systems.