Fig. 3

Preoperative and follow-up periapical radiographs (PAs) and cone-beam computed tomography (CBCT) images in corrected buccolingual views showing different patterns of radiographic healing. Case 1: (A–D): Maxillary second premolar presented at two-years after the surgery. (A and B) PAs showed complete healing. (C and D) Example of complete healing with respect to all three indices. Case 2: (E–H): Mandibular left central incisor that was followed up after one-year and eight-months. (E and F) Example of complete healing in PA. (G and H) Example of incomplete healing in CBCT. The arrow points to the cortical plate (C-index), which showed minor indentation and received a score of 1; meanwhile, the resection plane (R) and periradicular area (P) showed complete bone deposition, receiving a score of 2 each. Case 3: (I–L): Mandibular first molar at the one-year follow-up. (I) PA showing periapical radiolucency (PARL) associated with both mesial (M) and distal (D) roots. (J) Follow-up PA showed complete healing, but the density of the bone on the surgical side of the D root was lower than of the surrounding bone. (K) Preoperative CBCT showed PARL related to the D root of the first molar. The arrow points to the missed distolingual canal. (L) Follow-up CBCT showed complete re-establishment of the C-index (score 2) and partial improvement in the P-index (score 1), whereas no improvement was observed in the R-index (score 0). Case 4: (M–P) Maxillary first molar presented at one-year and six-months after the surgery with clinical signs and symptoms of failure. (M and N) PAs showing incomplete healing. (O) Preoperative CBCT of the mesiobuccal root with PARL. (P) Follow-up CBCT: the P-index reflects partial bone formation (a score of 1), but C- and R- indices reflect a lack of bone deposition (a score of 0 each)