The Effect of Earplugs on Gag Reflex and Patient Comfort in Root Canal Treatment

September 30, 2026 updated by: Beyhan Başkan

The Effect of Using Custom-Made Silicone Earplips on Gag Reflex Severity, Behavioral Responses, and Salivary Alpha-Amylase Levels as a Stress Biomarker in Patients Undergoing Root Canal Treatment: A Randomized Controlled Trial

This study evaluated whether wearing an earplug during root canal treatment reduces the gag reflex and the stress it causes. Forty adults who had a severe or very severe gag reflex were randomly divided into two groups. One group received an earplug in the ear opposite to the side being treated; the other group received standard treatment without an earplug. The severity of the gag reflex was scored by an observer, stress was measured using a saliva sample (salivary alpha-amylase), and treatment time and gag-related interruptions were recorded. The results showed that the earplug group had lower gag-reflex scores, lower stress levels, and shorter treatment times with fewer interruptions. No side effects were reported. These findings suggest that a simple, low-cost earplug may help patients who gag easily during dental treatment.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Background: An exaggerated gag reflex is a common problem during dental treatment, especially in endodontics, where uninterrupted working time and moisture control are essential. Pharmacological approaches carry risks, and evidence for non-pharmacological methods is limited. Earplug stimulation of the external auditory canal has been proposed as a simple, non-invasive way to suppress the gag reflex.

Objective: To evaluate the effect of earplug application during endodontic treatment on gag-reflex severity, physiological stress (salivary alpha-amylase, sAA), and clinical efficiency (treatment time and gag-related interruption ratio).

Methods: This prospective, randomized controlled trial enrolled 40 adults with severe or very severe gagging (Dickinson-Fiske Gagging Severity Index grade 4-5) requiring endodontic treatment. Participants were randomly allocated 1:1 to an earplug group or a control group. A custom-moulded silicone earplug was placed in the ear contralateral to the operating field. The operator and the outcome assessor were blinded by an identical adhesive ear cover applied to all participants; participants could not be blinded. Gag-reflex severity was scored with an 8-item behavioural scale (0-8). Unstimulated whole saliva was collected before and after treatment for sAA measurement. Total treatment time and gag-related interruption time were recorded, and the interruption ratio was calculated as (interruption time / total treatment time) × 100. Non-parametric tests and baseline-adjusted ANCOVA on log-transformed sAA were used.

Results: The earplug group had a lower behavioural gag-reflex score (median 3.0 vs 5.5; p < 0.01) and a more favourable severity distribution (trend p < 0.01). sAA decreased after treatment with the earplug but increased in controls (median change -31.8% vs +76.2%); baseline-adjusted post-treatment sAA was 59% lower with earplug use (geometric mean ratio 0.41, 95% CI 0.32-0.53; p < 0.001). Treatment time and the interruption ratio were markedly lower with earplug use (both p < 0.001). No adverse effects were observed.

Conclusions: Earplug application during endodontic treatment was associated with reduced gag-reflex severity, an attenuated physiological stress response, and improved procedural efficiency. As a simple, inexpensive, non-invasive technique, the earplug may be a useful adjunct for managing severe gagging in endodontic practice. Larger, multi-centre trials with patient-reported outcomes are warranted.

Trial registration: ClinicalTrials.gov, NCT07493200.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
40

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey (Türkiye)
      • Kahramanmaraş, Turkey (Türkiye), 46140
        • Kahramanmaraş Sütçü İmam Universty

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

Age over 18 years Need for endodontic treatment Score of 4 (severe gagging: occurs with all forms of treatment) or 5 (very severe gagging: makes treatment impossible) on the Dickinson and Fiske Gagging Severity Index (GSI)

Exclusion Criteria:

Systemic disease Pregnancy or lactation Diagnosed central or peripheral nervous system disorders Use of anti-emetic medication Ear infection or structural abnormality of the external auditory canal

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Experimental Group

Patients in this group (n=20) will have a custom-made silicone earplug placed in the ear opposite the side where the dentist is working during their root canal treatment. The earplug is fabricated immediately before the procedure using soft silicone material to ensure a comfortable, personalized fit. No other pharmacological or behavioral interventions for gag reflex control will be used.
Device: Custom-Made Silicone Earplug

A personalized earplug fabricated from a soft, two-component addition-cure silicone (C-type silicone), commonly used for dental impressions. The two components are mixed according to the manufacturer's instructions and gently injected into the patient's external auditory canal on the side contralateral to the tooth receiving treatment. The silicone is allowed to polymerize for approximately 2-3 minutes, creating a custom-fit plug that conforms precisely to the individual contours of the ear canal. This ensures comfortable, continuous, and gentle tactile stimulation to the walls of the ear canal throughout the entire root canal procedure. The earplug is removed at the end of the treatment and is for single-patient use only. No other devices or pharmacological agents are used in conjunction with this intervention.
No Intervention: Control Group

Patients in this group (n=20) will receive standard root canal treatment without any earplug placement. No interventions for gag reflex control will be used. All outcome measures (gag reflex severity, behavioral responses, treatment pause ratio, salivary alpha-amylase) will be collected in the same manner as for the experimental group.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Behavioural Gag-Reflex Score
Time Frame: Throughout the root canal procedure (continuous observation by a blinded assessor)

An 8-item behavioural observation scale (0-8) was used to quantify the intraoperative gag response. One point was assigned for each of: eye-squeezing, sweating, physical contraction, withdrawal, groaning, crying, breath-holding, and increased salivation. The total score was categorised as Mild (0-2), Moderate (3-4), Severe (5-6), or Very Severe (7-8).
Throughout the root canal procedure (continuous observation by a blinded assessor)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Behavioural Gag-Reflex Severity Distribution
Time Frame: Throughout the root canal procedure

The total 8-item behavioural score (0-8) was categorised as Mild (0-2), Moderate (3-4), Severe (5-6), or Very Severe (7-8). The distribution of these categories after treatment was compared between groups using the Cochran-Armitage trend test.
Throughout the root canal procedure
Gag-Related Interruption Ratio
Time Frame: Throughout the procedure

The cumulative duration of gag-related pauses was divided by total treatment time and multiplied by 100. Total treatment time was measured from the start of access-cavity preparation to completion of the root-canal filling.
Throughout the procedure
Salivary α-Amylase Activity
Time Frame: Immediately before and immediately after the procedure

Unstimulated whole saliva was collected before and after treatment, centrifuged (10,000 × g, 10 min, 4 °C), and stored at -80 °C. sAA activity was measured colorimetrically using a commercial kit (Elabscience, Cat. No. E-BC-K007-M) based on the DNS method; optical density was read at 540 nm.
Immediately before and immediately after the procedure
Total Treatment Time
Time Frame: Throughout the procedure

Time from start of access-cavity preparation to completion of root-canal filling, measured with a digital stopwatch.
Throughout the procedure

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Beyhan Başkan

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 12, 2025

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
February 5, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
February 5, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 19, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 19, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 25, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
October 5, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 30, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • HRÜ/25.09.54

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data (demographic, behavioural, salivary α-amylase, and procedural time data) will be shared. Requests should be directed to the corresponding author.

IPD Sharing Time Frame

Data will be available after publication of the study results and for 5 years thereafter.

IPD Sharing Access Criteria

De-identified IPD and supporting documents will be made available to researchers whose proposed use of the data has been approved by the corresponding author and the institutional ethics committee. Data will be shared for non-commercial research purposes only. Requests should be sent to beyhanbaskan@ksu.edu.tr.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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