Influence of Maintaining Apical Patency on Post-Endodontic Pain in Molars (IMAP-Pain)

Influence of Maintaining Apical Patency in Post-Endodontic Pain in Molars With Necrotic Pulp and Apical Periodontitis: A Randomized Controlled Trial

This randomized controlled trial will investigate if maintaining apical patency-a technique where a small file is gently moved past the root's end during cleaning-affects pain after a root canal. The study will include 48 adult patients needing root canal treatment on a back molar tooth with a dead nerve and infection at the root tip. Participants will be randomly assigned to one of two groups: one where the apical patency technique is used, and one where it is not. All other treatment steps will be identical. Patients will record their pain levels on a standard scale (0-100 mm Visual Analog Scale) at 6, 12, 24, 48, and 72 hours after the procedure. The goal is to determine if this specific technique influences the intensity and duration of post-treatment pain

Study Overview

• Status: Not yet recruiting
• Conditions: Periapical Periodontitis; Dental Pulp Necrosis
• Intervention / Treatment: Procedure: Patency Group; Procedure: Standard Root Canal Instrumentation

Detailed Description

BACKGROUND: Post-operative pain remains a significant challenge in endodontics, impacting patient satisfaction. The clinical practice of maintaining apical patency-passively keeping the apical foramen patent with a small file-is debated, with conflicting evidence on its impact on post-endodontic pain. This study aims to provide clear evidence from a robust randomized controlled trial.

OBJECTIVE: To determine the influence of maintaining apical patency on the intensity and duration of post-endodontic pain in molars with necrotic pulp and apical periodontitis.

METHODS:

Study Design: Single-center, randomized, controlled, parallel-group trial.

Setting: Department of Operative Dentistry, Saidu College of Dentistry, Swat.

Participants: 48 adult patients (aged 18-65, ASA I/II) with a single permanent molar diagnosed with necrotic pulp and symptomatic apical periodontitis. Patients with prior endodontic treatment, complex anatomy, systemic illness, pregnancy, recent analgesic use, or non-restorable teeth will be excluded.

Intervention:

Patency Group (Experimental): Following determination of working length with an electronic apex locator (verified radiographically), a pre-curved size #10 K-file will be passively advanced 1.0 mm beyond the major apical foramen before and after each successive instrumentation size.

Non-Patency Group (Active Comparator): Instrumentation will be carefully confined to the root canal space and will not proceed beyond the apical foramen.

Procedure: All participants will receive single-visit root canal treatment under local anesthesia and rubber dam isolation. Cleaning and shaping will be performed using a rotary instrument system. Irrigation will be performed with sodium hypochlorite and EDTA. Obturation will be completed with gutta-percha and sealer via a standardized technique, followed by a composite restoration.

Outcome Measure: The primary outcome is post-operative pain intensity, measured using a 100-mm Visual Analog Scale (VAS). Patients will self-record their pain levels at 6, 12, 24, 48, and 72 hours post-operatively.

Data Analysis: Data will be analyzed using SPSS Statistics v25. Descriptive statistics will summarize the data. The distribution of pain severity categories will be compared using the Chi-square test. Mean VAS scores between groups will be compared using independent samples t-tests (assuming normal distribution). A p-value of < 0.05 will be considered statistically significant.

• Study Type: Interventional
• Enrollment (Estimated): 48
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Faiz Rahman, BDS; Phone Number: +923451505838; Email: faizr3702@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:Adult patients aged 18-65 years.

Medically healthy, classified as American Society of Anesthesiologists (ASA) Physical Status I or II.

Presence of a single permanent molar tooth diagnosed with necrotic pulp and symptomatic apical periodontitis, and indicated for primary root canal treatment.

Patients who provide informed written consent to participate in the study. -

Exclusion Criteria:

Teeth with prior endodontic treatment or complex anatomy (e.g., calcified canals, severe curvature).

Patients with significant systemic illness (e.g., uncontrolled diabetes, immunocompromised status) or pregnancy.

History of analgesic intake within 72 hours prior to the root canal procedure.

Non-restorable teeth, teeth with severe periodontal disease (pocket depth >5mm), or teeth with root fractures.

Exclusion Criteria:

-

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Patency Group; : A #10 K-file is passively advanced 1.0 mm beyond the major apical foramen before and after each successive instrumentation size to maintain patency.	Procedure: Patency Group; The procedural technique of passively advancing a small endodontic file (size #10 K-file) 1 mm beyond the apical foramen before and after each larger instrument during root canal cleaning and shaping. This is done to prevent blockage of the apical portion of the canal.; Procedure: Standard Root Canal Instrumentation; Root canal instrumentation that is strictly confined to the canal space, terminating at the apical constriction (working length) and avoiding any instrumentation beyond the apical foramen.
Active Comparator: Non-Patency Group; Participants in this group will receive standard root canal treatment where instruments are carefully confined to the root canal space and do not proceed beyond the apical foramen. All other aspects of the treatment are identical to the Experimental arm.	Procedure: Patency Group; The procedural technique of passively advancing a small endodontic file (size #10 K-file) 1 mm beyond the apical foramen before and after each larger instrument during root canal cleaning and shaping. This is done to prevent blockage of the apical portion of the canal.; Procedure: Standard Root Canal Instrumentation; Root canal instrumentation that is strictly confined to the canal space, terminating at the apical constriction (working length) and avoiding any instrumentation beyond the apical foramen.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Post-operative Pain Intensity	Pain level measured using a 100-mm Visual Analog Scale (VAS). Patients self-report by marking a line on a 100-mm horizontal scale, where 0 mm = "no pain" and 100 mm = "worst imaginable pain". The score is the distance in mm from the left anchor.	6 hours after the completion of the root canal procedure
Post-operative Pain Intensity at 6 hours	Pain level measured using a 100-mm Visual Analog Scale (VAS). Patients self-report by marking a line on a 100-mm horizontal scale, where 0 mm = "no pain" and 100 mm = "worst imaginable pain". The score is the distance in mm from the left anchor.	6 hours after the completion of the root canal procedure.
Post-operative Pain Intensity at 12 hours	Pain level measured using a 100-mm Visual Analog Scale (VAS). Patients self-report by marking a line on a 100-mm horizontal scale, where 0 mm = "no pain" and 100 mm = "worst imaginable pain". The score is the distance in mm from the left anchor.	12 hours
Post-operative Pain Intensity at 48 hours	Pain level measured using a 100-mm Visual Analog Scale (VAS). Patients self-report by marking a line on a 100-mm horizontal scale, where 0 mm = "no pain" and 100 mm = "worst imaginable pain". The score is the distance in mm from the left anchor.	48 hours
Post-operative Pain Intensity	Pain level measured using a 100-mm Visual Analog Scale (VAS). Patients self-report by marking a line on a 100-mm horizontal scale, where 0 mm = "no pain" and 100 mm = "worst imaginable pain". The score is the distance in mm from the left anchor.	12 hours after the completion of the root canal procedure
Post-operative Pain Intensity	Pain level measured using a 100-mm Visual Analog Scale (VAS). Patients self-report by marking a line on a 100-mm horizontal scale, where 0 mm = "no pain" and 100 mm = "worst imaginable pain". The score is the distance in mm from the left anchor.	24 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
ncidence of Post-operative Pain Severity	The proportion of participants in each group reporting different levels of pain severity, categorized based on their VAS scores. The categories are: No Pain (VAS = 0 mm), Moderate Pain (VAS = 1-54 mm), and Severe Pain (VAS = 55-100 mm).	Assessed at 6, 12, 24, 48, and 72 hours after the procedure
ncidence of Post-operative Pain Severity	The proportion of participants in each group reporting different levels of pain severity, categorized based on their VAS scores. The categories are: No Pain (VAS = 0 mm), Moderate Pain (VAS = 1-54 mm), and Severe Pain (VAS = 55-100 mm).	Assessed at 6, 12, 24, 48, and 72 hours after the procedure. The data from all time points will be aggregated to compare the overall distribution of pain severity between groups.

Collaborators and Investigators

• Sponsor: College of Physicians and Surgeons Pakistan

Study record dates

Study Major Dates

• Study Start (Estimated): February 10, 2026
• Primary Completion (Estimated): May 10, 2026
• Study Completion (Estimated): October 10, 2026

Study Registration Dates

• First Submitted: November 16, 2025
• First Submitted That Met QC Criteria: November 16, 2025
• First Posted (Actual): November 20, 2025

Study Record Updates

• Last Update Posted (Actual): November 20, 2025
• Last Update Submitted That Met QC Criteria: November 16, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Periodontal Diseases; Mouth Diseases; Stomatognathic Diseases; Pathologic Processes; Periapical Diseases; Jaw Diseases; Dental Pulp Diseases; Tooth Diseases; Necrosis; Periodontitis; Pathological Conditions, Signs and Symptoms; Periapical Periodontitis; Dental Pulp Necrosis
• Other Study ID Numbers: SCD-Endo-Patency-001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No