Fig. 1

The modified Chen et al. criteria for 3-dimensional radiographic evaluation after endodontic microsurgery. Cortical plate (access bony window) C-index. (A) Score 2: the cortical plate is re-established and flat. (B) Score 1: the cortical plate is re-established, but concave or with minor indentations. (C) Score 0: the cortical plate has not been re-established or is only partially re-established. Resection plane (cut root face) R-index. (D) Score 2: complete bone deposition on the resection plane (complete formation of periodontal ligament [PDL] space of normal width). (E) Score 1: partial bone deposition on the resection plane (partial formation of PDL space). (F) Score 0: no bone deposition on the resection plane (no formation of PDL). (G) Periradicular area P-index. (G) Score 2: complete bone formation in the periradicular area. (H) Score 1: partial bone formation in the periradicular area that appears to be smaller than the lesion size in the preoperative cone-beam computed tomography regardless of the R or C indices. (I) Score 0: no apparent bone formation around the periradicular area regardless of the R or C index