Postoperative Pain After OCT or EDTA Irrigation in Regenerative Endodontic Treatment

Necrotic immature permanent teeth with apical periodontitis present a clinical challenge because incomplete root development is associated with thin dentinal walls, an open apex, and an increased risk of root fracture. Regenerative endodontic treatment is a biologically based procedure that aims to control intracanal infection, promote healing of the periapical tissues, and allow continued root development.

Successful regenerative endodontic treatment requires effective root canal disinfection while preserving an environment that supports the survival and activity of stem cells from the apical papilla. Ethylenediaminetetraacetic acid (EDTA) is commonly used in regenerative procedures because of its chelating properties, its ability to modify the dentin surface, and its potential to promote the release of dentin-derived bioactive molecules. Octenidine dihydrochloride (OCT) is a broad-spectrum antiseptic that has demonstrated antimicrobial activity and potentially favorable biological effects on dental-derived stem cells. However, clinical evidence regarding the use of OCT during regenerative endodontic treatment remains limited.

This prospective, participant-blinded, parallel-group randomized clinical trial included 40 systemically healthy patients aged 9 to 16 years who had a necrotic immature permanent tooth with apical periodontitis. Eligible teeth had Cvek stage 2 or 3 root development and a baseline Periapical Index score between 2 and 4. Each participant contributed one tooth to the study.

Participants were randomly assigned in a 1:1 ratio to one of two irrigation groups:

• The OCT group received 0.1% octenidine dihydrochloride.
• The EDTA group received 17% ethylenediaminetetraacetic acid.

Regenerative endodontic treatment was performed in two visits. During the first visit, the root canal was initially irrigated with 1.5% sodium hypochlorite. The allocated OCT or EDTA solution was then applied and ultrasonically activated. Calcium hydroxide was placed as an intracanal medicament, and the access cavity was temporarily sealed.

The second visit was performed approximately two weeks later. After removal of the intracanal medicament, the root canal was irrigated again according to the allocated protocol, and the irrigant was ultrasonically activated. Apical bleeding was induced to create an intracanal blood clot. Biodentine was placed over the blood clot as a coronal barrier, and the tooth was permanently restored with resin composite.

The primary outcome was postoperative pain intensity, which was recorded using a 0-100 numerical rating scale at 6, 12, and 24 hours and daily from day 2 through day 7 after the second treatment visit. Secondary outcomes included analgesic consumption and the occurrence of flare-up, defined as severe postoperative pain and/or swelling requiring an unscheduled clinical visit.

Inclusion criteria

• Systemically healthy status classified as American Society of Anesthesiologists class I;
• An immature permanent tooth with pulp necrosis and apical periodontitis;
• Cvek stage 2 or 3 root development;
• Preoperative pain below 40 on a 0-100 numerical rating scale (NRS);
• A baseline Periapical Index (PAI) score between 2 and 4;
• A tooth considered restorable and suitable for RET; and
• Willingness of the participant and legal representative to comply with postoperative assessment and follow-up requirements.

Exclusion criteria

• systemic disease
• bruxism or another parafunctional habit
• had used analgesics within 12 hours before treatment
• severe root canal curvature
• vertical root fracture