Ultrasonic Activated Irrigation and Intracanal Cryotherapy for Reducing Pain After Root Canal Treatment

Postoperative pain remains one of the most common complications following root canal treatment and may negatively affect patient comfort and treatment acceptance. Various factors, including preoperative status, instrumentation techniques, and irrigation protocols, influence the incidence and severity of post-endodontic pain.

Ultrasonic activated irrigation (UAI) enhances the effectiveness of irrigants by generating acoustic streaming and cavitation, thereby improving debris removal, smear layer elimination, and disinfectant penetration into the root canal system. Intracanal cryotherapy, which involves the application of cold saline as a final irrigant, has been proposed as a non-pharmacological method to reduce postoperative pain by decreasing tissue temperature and exerting anti-inflammatory effects.

This study is a single-center, parallel two-arm, single-blinded randomized controlled trial conducted at the Department of Operative Dentistry and Endodontics, Sardar Begum Dental College, Peshawar, Pakistan. A total of 60 patients aged 20 to 50 years diagnosed with symptomatic irreversible pulpitis in mandibular first or second molars will be enrolled.

Eligible participants will be randomly allocated into two groups using a computer-generated randomization sequence with allocation concealment through sealed opaque envelopes. Group A (control group) will receive ultrasonic activated irrigation without intracanal cryotherapy, whereas Group B (intervention group) will receive ultrasonic activated irrigation followed by intracanal cryotherapy using 0.9% saline at 1.5-2.5°C for 5 minutes.

All treatments will be performed in a single visit under local anesthesia and rubber dam isolation using standardized clinical protocols. Root canal preparation will be carried out using the ProTaper Universal rotary system. Ultrasonic activation will be performed for one minute per canal. Following obturation and permanent restoration, postoperative pain will be assessed using a 10-point Visual Analogue Scale (VAS).

Pain scores will be recorded at 12, 24, 48, and 72 hours postoperatively through telephone follow-up by a blinded assessor. The primary outcome measure is postoperative pain intensity. Analgesic consumption and adverse events will also be documented.

The findings of this study may provide evidence regarding the effectiveness of intracanal cryotherapy as an adjunct to ultrasonic activated irrigation for reducing postoperative pain following single-visit root canal treatment in teeth with symptomatic irreversible pulpitis.

Inclusion criteria

• 1. Patients who are medically fit (ASA Physical Status I) and aged between 20 and 50 years will be recruited for the study.

• Mandibular first or second molars exhibiting signs of symptomatic irreversible pulpitis, identified through an extended sensitivity to cold testing and/or a positive electric pulp test.

3.Vital pulp with no signs of apical pathology (normal periapical radiograph, no swelling, sinus tract, or mobility).

• Mature roots with closed apices and no prior root canal treatment. 5. Willing to undergo single-visit treatment and comply with follow-up.

Exclusion criteria

• 1.Use of analgesics or NSAIDs within 12 hours prior to treatment. 2.Pregnant or lactating women. 3.Presence of systemic illness or allergy to any materials used in the study. 4.Teeth with:

• Non-vital pulp, periapical radiolucency, or sinus tract.
• Mobility > Grade I or periodontal pockets > 5 mm.
• Resorption, calcification, or non-restorable crown structure. 5.Third molars (wisdom teeth). 6.Endodontically treated tooth. 7.Inability or unwillingness to follow study instructions or complete follow-up.