The potential of a surface pre‐reacted glass root canal dressing for treating apical periodontitis in rats

Aim To evaluate the efficacy of a prototype root canal dressing containing surface pre‐reacted glass–ionomer (S‐PRG) fillers on repairing induced periapical lesions in a rat model. Calcium hydroxide [Ca(OH)2] was applied as a comparison in the healing process. Methodology The pulp chambers of the maxillary first molars in 64 male Wistar rats aged 16 weeks were opened to induce periapical lesions. After 28 days, the mesial canal of each tooth was prepared, irrigated with 2.5% sodium hypochlorite only (control group: irrigation) or followed by the respective dressing [Ca(OH)2 group, irrigation + Ca(OH)2; S‐PRG group, irrigation + S‐PRG] and restored with composite resin for 3 or 7 days (10/group). Four rats with healthy molars were used as blank controls. Descriptive analysis of the periapical radiographs, haematoxylin and eosin staining and immunohistochemical observation was performed 3 and 7 days after treatment. The periapical grey value, CD68 macrophages and osteoclasts (cathepsin‐K) were quantified and statistically analysed with Tukey’s honest significant difference test. A significant difference was achieved when P values were