Aim: This clinical study aims to compare post-operative pain after single-visit root canal treatment of teeth with asymptomatic apical periodontitis using epoxy-resin based AH Plus and calcium silicate based Endosequence BC sealers with or without sonic activation.

Materials and Methods: The study included 72 individuals having one first or second mandibular premolar tooth with asymptomatic apical periodontitis. They were randomly divided into 4 groups according to the root canal sealer (AH Plus or Endosequence BC) and activation protocol (sonic activation or non-activation) (n=18). Participants were ask to rate their post-operative pain intensity on a NRS scale as none, minimal, moderate, or severe after 24 h, 48 h, 72 h and 7 days following treatment. Patients were also asked to record the number of prescribed analgesic medication tablets (ibuprofen 400 mg) taken. The collected data were statistically analyzed at 0.05 significance level.

Root Canal Treatment After inferior alveolar nervus block anesthesia with 4% Articaine with 1:100,000 adrenaline, the tooth was isolated with a rubber dam. The access cavity was opened using high-speed diamond round burs under water cooling. The working length (WL) was set at 0.5 mm shorter than the 0.0 reading using a 15 K-type file and apex locator (Morita Root ZX, Japan) and checked with radiographs. The root canals were prepared with Resiproc (Resiproc, VDW, Munich, Germany) R25 and R40 files, respectively, at the WL using the crown down technique. A total of 20 mL of 2.5% sodium hypochlorite (NaOCl) was used with a 30-gauge needle (Max-i-Probe; Dentsply Sirona) during preparation. 5 mL of distilled water was left in the canal for 1 min to neutralize the effect of NaOCl, and then the root canals were irrigated with 3 ml of 17% ethylene diamine tetra acetic acid (EDTA). EDTA was activated for 3 × 20s with the EA 25/04 tip 2 mm shorter than the WL. The EA tip was used with 2-4 mm vertical strokes. The root canals were irrigated with 5 mL distilled water and dried with paper points.

The subjects were divided into four groups for root filling. Randomization was performed using online software (www.randomizer.org) with a four-block-sized block randomization technique to ensure even distribution between the groups (allocation ratio 1:1:1:1). A co-investigator managed the allocation and reported the allocated treatment procedure to the operator. The operator could not be blinded due to the different stages of the treatment protocols. The patients were blinded to the chosen root canal sealer and activation protocol.

Inclusion Criteria:

• Mandibular first and second premolar teeth diagnosed with asymptomatic apical periodontitis
• Single rooted teeth with a single canal.

Exclusion Criteria:

• Previous root canal treatment
• Use of any analgesic or antibiotics in the last 7 days
• Symptomatic teeth
• Sinus tract
• Presence of advanced periodontal problem (probing depth >4 mm)
• Complications during treatment such as broken file, ledging
• Teeth with extensive coronal destruction.

The patients were blinded to the chosen root canal sealer and activation protocol.