A Al-Sabawi, N. 2013. Evaluation of Two Rotary Nickel-Titanium Systems for Gutta Percha Removal during Endodontic Retreatment. Al-Rafidain Dental Journal. 13, 1 (Jan. 2013), 21–28. DOI:https://doi.org/10.33899/rden.2012.84675.