Hyaluronic Acid in Endodontic Microsurgery

This randomized clinical trial (RCT) will evaluate the effectiveness of cross-linked hyaluronic acid as an adjunct to endodontic microsurgery in adult patients with apical periodontitis affecting maxillary or mandibular first molars. Participants previously treated with non-surgical endodontic therapy will be allocated to either endodontic microsurgery with cross-linked hyaluronic acid application (test group) or the same surgical procedure without adjunctive material (control group), with 12 months of follow-up.

The study hypothesis is that cross-linked hyaluronic acid improves soft- and hard-tissue healing, reduces postoperative inflammation and pain, and supports more stable surgical outcomes. Primary outcomes include early soft tissue healing (Early Wound Healing Score, day 4) and postoperative pain (visual analogue scale). Secondary outcomes include periapical healing assessed by blinded evaluators on periapical radiographs (Molven criteria) at 3, 6, and 12 months, and on CBCT scans (PENN 3D criteria) at 6 and 12 months, as well as cortical plate healing (RAC/B index). This study aims to provide clinical evidence on the potential regenerative and anti-inflammatory benefits of cross-linked hyaluronic acid in endodontic microsurgery.