The Effect of Apical Patency on Postoperative Pain Following Root Canal Treatment

The goal of this randomized controlled clinical trial was to evaluate whether implementing apical patency affects the intensity of postoperative pain after single-visit root canal treatment in asymptomatic, vital, single-rooted teeth.

The main question it aims to answer is:

Does maintaining apical patency by gently extending a #10 K-file 1 mm beyond the working length during canal shaping influence postoperative pain compared with instrumentation confined within the working length?

In the patency group, the working length was determined with an electronic apex locator and radiograph, and then apical patency was maintained by passively extending a #10 K-file 1 mm beyond the working length at each instrument change to prevent apical blockage, remove debris, and facilitate irrigant delivery to the apical terminus.

In the non-patency group, the working length was likewise established with an electronic apex locator and radiograph, but all subsequent instrumentation was confined within the working length and no file was advanced beyond the apical foramen.

In both groups, all other clinical procedures-including anesthesia, rubber dam isolation, access cavity preparation, rotary canal shaping with the One Curve NiTi system, standardized irrigation with 2.5% NaOCl and 17% EDTA, obturation with gutta-percha and epoxy resin-based sealer, and definitive composite restoration-were performed in a single visit using the same protocol. Postoperative pain was recorded on a Numerical Rating Scale (NRS) at 0-6, 6-12, 12-24, 24-36, and 36-48 hours, and analgesic intake within 48 hours was documented.

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Key information

Conditions

Postoperative Pain After Endodontic Treatment

Age range

18 year–65 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

Individuals aged 18-65 years, classified as ASA I or ASA II according to the American Society of Anesthesiologists (ASA), who had not taken analgesics for at least 6 hours prior to treatment.
Asymptomatic, single-rooted vital teeth without spontaneous pain (including teeth perforated during prosthetic preparation or teeth adjacent to a cyst in an area scheduled for cyst surgery).
Radiographic evidence of mature apices with no periapical pathology; periodontal probing depth ≤ 3 mm; and gingival health meeting Glickman's criteria.
Individuals who are literate, able to provide written informed consent, and capable of understanding and using the pain scale.

Exclusion criteria

Patients who are pregnant or have a cardiac pacemaker.
Patients who used antibiotics within the past month or who required antibiotic prophylaxis.
Presence of extensive restorations in the tooth of interest.
Patients reporting concurrent pain in adjacent teeth.
Dental or orofacial pain of non-endodontic origin.

Treatment and study plan

Root canal treatment with apical patency

Procedure

Single-visit root canal treatment of asymptomatic vital single-rooted teeth in which apical patency is maintained. After working length determination with an electronic apex locator and radiographic confirmation, a #10 K-file is gently extended 1 mm beyond the working length at each instrument change to prevent apical blockage, remove debris, and facilitate irrigant delivery to the apical terminus. All other steps, including anesthesia, rubber dam isolation, access cavity preparation, rotary shaping with the One Curve NiTi system, standardized irrigation with 2.5% NaOCl and 17% EDTA, obturation, and definitive composite restoration, follow a standardized protocol.

Root canal treatment without apical patency

Procedure

Single-visit root canal treatment of asymptomatic vital single-rooted teeth in which apical patency is not maintained. After working length determination with an electronic apex locator and radiographic confirmation, all subsequent instrumentation is confined within the working length and no file is advanced beyond the apical foramen. All other steps, including anesthesia, rubber dam isolation, access cavity preparation, rotary shaping with the One Curve NiTi system, standardized irrigation with 2.5% NaOCl and 17% EDTA, obturation, and definitive composite restoration, follow the same standardized protocol as in the patency group.

Primary outcomes

Numerical Rating Scale (NRS)

Time frame: Up to 48 hours after treatment.

The numerical rating scale for pain is an 11-point scale from 0 to 10, where 0 means no pain and 10 means the worst pain imaginable. The patient is asked to choose the number that best represents the intensity of pain he or she feels at that moment. It is used to assess the severity of postoperative pain and to help evaluate the need for and response to analgesic medication. Also called NRS.

Sponsors and collaborators

Lead sponsor

Cukurova University

Other

Registry information

Official study title

The Effect of Apical Patency on Postoperative Pain Following Root Canal Treatment of Single-Rooted Teeth: A Randomized Controlled Clinical Trial

Important dates

Study start: 2024
Primary completion: 2024
Study completion: 2025
First posted: Nov 18, 2025
Registry last updated: Nov 18, 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