The Effect of Different Sodium Hypochlorite Concentrations and Activation Techniques on Postoperative Pain

The goal of this clinical trial was to evaluate the effect of different sodium hypochlorite (NaOCl) concentrations and irrigation activation techniques on the intensity of postoperative pain following single-visit root canal treatment in molar teeth with asymptomatic chronic apical periodontitis.

The primary research questions of this study were as follows:

Does using 2.5% or 5.25% sodium hypochlorite solution during root canal irrigation influence the severity of postoperative pain? Do activation techniques such as sonic activation using EDDY (a flexible polyamide tip-driven sonic irrigation device operating at 6,000 Hz; VDW GmbH, Munich, Germany) or passive ultrasonic irrigation (PUI) significantly reduce postoperative pain compared to conventional needle irrigation? In the non-activation groups, root canals were irrigated with 2.5% or 5.25% NaOCl using a 30-gauge side-vented needle without any further activation.

In the EDDY groups, root canals were irrigated using 2.5% or 5.25% NaOCl, followed by activation with a flexible polyamide EDDY tip (25/04) at 6,000 Hz, three times for 20 seconds.

In the PUI groups, root canals were irrigated using 2.5% or 5.25% NaOCl, and then subjected to passive ultrasonic activation with a suitable ultrasonic tip three times for 20 seconds, without contacting dentinal walls.

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Key information

Conditions

Chronic Apical Periodontitis Neurologic Manifestations Pain Pain, Postoperative Pathologic Processes Pathological Conditions, Signs and Symptoms Postoperative Complications Signs and Symptoms

Age range

16 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Cukurova University

Adana, Sarıçam, 01250, Turkey (Türkiye)

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Patients aged between 16 and 60 years
Systemically healthy individuals
Presence of mandibular or maxillary first or second molar diagnosed with asymptomatic chronic apical periodontitis
Negative response to electric pulp test, cold test, percussion and palpation tests
Teeth eligible for single-visit root canal treatment
Patients who provided written informed consent

Exclusion criteria

Pregnant or breastfeeding individuals
Patients with uncontrolled systemic diseases (e.g., uncontrolled hypertension, uncontrolled diabetes mellitus, chronic renal failure, hematologic disorders)
Patients undergoing chemotherapy or radiotherapy
Individuals with infective endocarditis or immunosuppressive conditions
Patients requiring antibiotic prophylaxis prior to dental treatment
Use of anti-inflammatory or analgesic medications within 24 hours before treatment
Teeth with calcified canals, internal/external resorption, or root fractures
Patients unable to attend follow-up appointments or complete pain assessment forms

Treatment and study plan

EDDY Sonic Activation System

Device

EDDY is a sonic irrigation activation system operating at 6,000 Hz frequency with a flexible polyamide tip (25/04). In endodontic procedures, the EDDY tip is inserted 2 mm short of the working length into the root canal and activated for 20 seconds in three consecutive cycles. The sonic activation enhances irrigant agitation through cavitation and acoustic streaming, improving cleaning efficacy within the root canal system, especially in curved canals. The device does not contact dentin walls, reducing the risk of iatrogenic damage. In this study, EDDY was used to activate sodium hypochlorite solutions of either 2.5% or 5.25% concentration depending on the assigned group.

Passive Ultrasonic Irrigation (PUI)

Device

Passive Ultrasonic Irrigation (PUI) involves the use of an ultrasonically activated file or tip inserted into the root canal 2 mm short of the working length, without contacting the dentinal walls. The ultrasonic tip is operated in a non-cutting, passive manner to generate acoustic streaming and cavitation within the irrigant. In this study, after initial irrigation with 2 mL of sodium hypochlorite (either 2.5% or 5.25%, depending on the group), ultrasonic activation was performed for 20 seconds in three consecutive cycles. Each activation was followed by 1 mL NaOCl irrigation. This method is designed to enhance the penetration and effectiveness of irrigants, especially in anatomically complex areas of the root canal system.

Primary outcomes

Visual Analogue Scale (VAS)

Time frame: up to 72 hours

The visual analog scale for pain is a straight line with one end meaning no pain (0) and the other end meaning the worst pain (10) imaginable. A patient marks a point on the line that matches the amount of pain he or she feels. It may be used to help choose the right dose of pain medicine. Also called VAS.

Sponsors and collaborators

Lead sponsor

Cukurova University

Other

Registry information

Official study title

The Effect of Different Sodium Hypochlorite Concentrations and Activation Techniques on Postoperative Pain in Permanent Molars With Chronic Apical Periodontitis: A Randomized Controlled Trial

Important dates

Study start: 2024
Primary completion: 2025
Study completion: 2025
First posted: Jun 24, 2025
Registry last updated: Jun 27, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed