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Effect of Integrated Apex Locator Motor Modes on Postoperative Pain in Endodontic Retreatment

Effect of Integrated Electronic Apex Locator Modes on Postoperative Pain After Root Canal Retreatment: A Randomized Controlled Clinical Trial

Status
Completed
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07527897
Acronym
EAL-Pain
Enrollment
144
Registered
2026-04-14
Start date
2025-08-13
Completion date
2025-10-17
Last updated
2026-04-14

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Apical Periodontitis, Endodontic Retreatment, Postoperative Pain

Keywords

Electronic apex locators, Time factors, Endodontics, Retreatment, Postoperative pain

Brief summary

This randomized controlled clinical trial aimed to evaluate the effect of different integrated electronic apex locator (EAL) modes on postoperative pain following nonsurgical endodontic retreatment. A total of 144 patients requiring retreatment of mandibular premolar teeth with periapical lesions were randomly assigned to four groups. In the control group, working length was determined using a conventional electronic apex locator. In the experimental groups, an integrated EAL motor was used with three different modes: apical reverse, apical slow down, and apical stop. All procedures were performed under standardized conditions. Postoperative pain was assessed using a numeric rating scale (NRS) at 6 and 12 hours and on days 1, 2, 3, 5, and 7 after treatment. The study aimed to determine whether simultaneous working length control using integrated EAL modes influences postoperative pain compared with conventional working length determination.

Detailed description

Accurate determination and maintenance of working length is essential for successful endodontic retreatment. Electronic apex locators (EALs) are widely used to improve the accuracy of working length determination. Recently, endodontic motors with integrated EAL systems have been developed, enabling simultaneous working length control during canal instrumentation. These systems incorporate different automatic apical control modes, including apical reverse, apical slow down, and apical stop, which may influence clinical outcomes such as postoperative pain. This randomized controlled clinical trial was conducted to evaluate the effects of different integrated EAL modes on postoperative pain following nonsurgical endodontic retreatment. A total of 144 systemically healthy patients with previously treated single-rooted mandibular premolars diagnosed with asymptomatic apical periodontitis were included. Patients were randomly allocated into four groups (n=36 each): (1) conventional electronic apex locator (control group; Root ZX Mini), (2) integrated EAL motor with apical reverse mode, (3) apical slow down mode, and (4) apical stop mode (Ai Motor; Motopex; Woodpecker). In the control group, working length was determined using a conventional EAL and confirmed radiographically. In the experimental groups, working length determination and instrumentation were performed simultaneously using an integrated EAL motor according to the assigned apical mode. All retreatment procedures were completed in a single visit under standardized clinical conditions by a single experienced operator. Root canal filling materials were removed, canals were prepared using rotary instruments, and irrigation was performed using 2.5% sodium hypochlorite and 17% EDTA with ultrasonic activation. Final obturation was carried out using a single-cone technique with a bioceramic sealer. Postoperative pain was assessed using an 11-point numeric rating scale (NRS) at 6 and 12 hours and on days 1, 2, 3, 5, and 7 after treatment. The primary outcome measure was postoperative pain intensity. The study evaluated whether different simultaneous working length control strategies using integrated EAL modes affect postoperative pain compared with the conventional electronic apex locator method.

Interventions

Working length was determined using a conventional electronic apex locator (Root ZX Mini). The measurement was confirmed radiographically, and endodontic retreatment procedures were completed under standardized clinical conditions.

DEVICEIntegrated Apex Locator Motor

Working length determination and canal instrumentation were performed simultaneously using an integrated electronic apex locator motor (Ai Motor, Motopex, Woodpecker). The device operates with different apical control modes, including apical reverse, apical slow down, and apical stop, which automatically respond when the file reaches the predefined working length.

Sponsors

Recep Tayyip Erdogan University
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)

Masking description

Due to the nature of the interventions, the operator could not be blinded. However, participants and the outcome assessor were blinded to group allocation. The statistician was also blinded during data analysis.

Intervention model description

Participants were randomly assigned to four parallel groups to compare conventional electronic apex locator use with three different integrated apex locator motor modes (apical reverse, apical slow down, and apical stop) during endodontic retreatment.

Eligibility

Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No

Inclusion criteria

* Systemically healthy patients aged between 18 and 65 years * Patients requiring nonsurgical endodontic retreatment * Single-rooted, single-canal mandibular premolar teeth * Diagnosis of asymptomatic apical periodontitis * Presence of a well-defined periapical radiolucency (PAI \> 4) * Teeth with previous root canal treatment performed at least 4 years prior * Root canal fillings extending to at least the apical third without overfilling

Exclusion criteria

* Patients with symptoms such as pain, swelling, or sinus tract * Patients with a history of smoking or alcohol use * Teeth with open apices or root resorption * Teeth with intraradicular posts * Teeth with insufficient coronal tooth structure * Teeth with perforation, instrument fracture, or overfilled canals * Teeth with root curvature greater than 30 degrees * Teeth with periodontal disease or probing depth \>3 mm * Cases not suitable for single-visit retreatment * Patients who used analgesics within 12 hours prior to treatment * Patients who used antibiotics within the last month * Patients with cognitive impairment or psychological disorders

Design outcomes

Primary

MeasureTime frameDescription
Primary Outcome Measure6 hours, 12 hours, and days 1, 2, 3, 5, and 7 after treatmentPostoperative pain intensity was assessed using an 11-point numeric rating scale (NRS), where 0 indicates no pain and 10 indicates the worst possible pain. Pain scores were recorded at 6 and 12 hours and on days 1, 2, 3, 5, and 7 following endodontic retreatment.

Countries

Turkey (Türkiye)

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Apr 15, 2026