“…This difference could have affected the present study outcome, if MTA would have been used as the retrograde filling material. This is in line with a study from Favieri and co-workers who reported that the use of MTA in combination bone-substitute in large bony defect can benefit the healing outcome [21]. The mean distance between the root-end filler and the bone among the groups (Table 1), thus the size of the zone without hard tissue seems not to depend on whether the resection defect has been filled or not.…”