Fig. 2

Modified EAP in rats leads to progressive bone loss. a Oral images of modified endodontic procedures of EAP to the mandibular first molar. a1 Access to the pulp chamber gained through the distal root canal. a2 Pulp of the distal root canal largely removed. a3 Irrigation by PBS. a4 Drying by paper points. a5 Addition of PBS to the distal root canal. a6–8 Sealing of the cavity. Scale bar: 500 µm. b Time course of the observation. b1 Schematics of the time course of induction and harvest. EAP was induced in seven-week-old rats. X-ray images after 2 weeks, 4 weeks and 6 weeks of observation are shown on the right side. b2 HE staining of the mandibular first molar; residual distal dental pulp (red asterisk) was sealed as persistent mild irritants by composite resin (b1 black arrow) compared to the normal pulp (black asterisk). Red dotted area, radiolucent apical periodontitis lesion in b1–2. m, mesial; d, distal; dr, distal root of the mandibular first molar. Scale bar: 100 µm