Comfort-in Needle-Free Injection System in Pediatric Dental Anesthesia

May 6, 2026 updated by: Semih Ercan Akgun, Ondokuz Mayıs University

Assessing the Efficacy of the Comfort-in Needle-Free Injection System for Managing Pain and Anxiety During Pediatric Dental Injections: A Randomized Split-Mouth Clinical Trial

This randomized split-mouth clinical trial evaluated the efficacy of the Comfort-in needle-free injection system compared with conventional dental injection for local anesthesia during pulpotomy treatment in children.

Sixty children aged 5 to 8 years who required bilateral pulpotomy of primary first molars were included. Each participant received both anesthesia techniques in separate treatment sessions with an interval of at least one week. The order of anesthesia techniques was randomized: 30 children received conventional dental injection in the first session and Comfort-in needle-free injection in the second session, while the remaining 30 children received the interventions in the reverse order.

Pain perception during anesthesia administration and pulpotomy was assessed using the Face, Legs, Activity, Cry, Consolability scale and the Wong-Baker FACES Pain Rating Scale. Physiological parameters, including blood pressure, pulse, and oxygen saturation, were recorded before anesthesia, after anesthesia, and after pulpotomy. The amount of anesthetic solution used, duration of anesthetic effect, postoperative complications, and patient preference were also recorded.

The study was designed to determine whether the Comfort-in needle-free injection system could provide effective local anesthesia for pediatric pulpotomy while reducing injection-related pain, physiological stress responses, anesthetic volume, duration of postoperative numbness, and postoperative complications compared with conventional dental injection.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Local anesthesia administration is one of the major sources of pain, fear, and anxiety in pediatric dental patients. Conventional dental injections may cause discomfort due to needle penetration, tissue pressure, and deposition of anesthetic solution. These experiences may negatively affect child cooperation and future dental attendance. Needle-free injection systems have been developed as an alternative method to deliver local anesthetic solution without needle penetration.

This randomized split-mouth clinical trial compared the Comfort-in needle-free injection system with conventional dental injection in children requiring pulpotomy treatment of bilateral primary first molars. The split-mouth design was used to allow each child to serve as his or her own control, thereby reducing interindividual variability in pain perception and physiological responses.

A total of 60 children aged 5 to 8 years were included. All participants required pulpotomy treatment of bilateral primary first molars located in either the maxilla or mandible. Eligible children had no previous experience with local anesthesia or dental treatment, had no systemic disease or mental disability, had not used medications that could affect pain perception, and demonstrated positive or definitely positive behavior according to the Frankl Behavior Rating Scale during the initial examination.

Each child received both anesthesia techniques in two separate clinical sessions with a minimum interval of one week. In one session, conventional local anesthesia was administered using a dental injector after topical anesthetic application. In the other session, local anesthesia was administered using the Comfort-in needle-free injection system after topical anesthetic application. The sequence of interventions was randomized. Thirty children received conventional injection first and Comfort-in needle-free injection second; the remaining 30 children received Comfort-in needle-free injection first and conventional injection second.

In the conventional injection session, the injection site was dried and topical anesthetic spray was applied for 60 seconds. Local anesthetic solution containing articaine hydrochloride with epinephrine 1:100,000 was then administered using a 27-gauge dental injector. In the Comfort-in session, the injection site was similarly dried and topical anesthetic spray was applied for 60 seconds. Articaine hydrochloride with epinephrine 1:100,000 was administered using the Comfort-in needle-free injection system.

Pain during anesthesia administration and pulpotomy was assessed using two validated pediatric pain assessment tools: the Face, Legs, Activity, Cry, Consolability scale and the Wong-Baker FACES Pain Rating Scale. Physiological parameters, including systolic blood pressure, diastolic blood pressure, pulse, and oxygen saturation, were recorded before anesthesia, after anesthesia, and after pulpotomy. The total amount of anesthetic solution used, duration of anesthetic effect, postoperative complications, and the child's preference for anesthesia technique were also recorded.

The primary aim of the study was to compare pain perception during local anesthesia administration between the Comfort-in needle-free injection system and conventional dental injection. Secondary aims included comparing anesthetic efficacy during pulpotomy, physiological responses, amount of anesthetic solution required, duration of anesthetic effect, postoperative complications, and patient preference between the two anesthesia techniques.

Study Type

Interventional

Enrollment (Actual)

60

Phase

  • 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)
    • Rize Province
      • Rize, Rize Province, Turkey (Türkiye), 53000
        • Recep Tayyip Erdoğan University

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

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Children aged 5 to 8 years.
  • Children requiring pulpotomy treatment of bilateral primary first molars located in either the maxilla or mandible.
  • Children with no previous experience of local anesthesia or dental treatment.
  • Children who showed positive or definitely positive behavior according to the Frankl Behavior Rating Scale during the initial examination.
  • Children with no systemic disease.
  • Children with no mental or cognitive disability.
  • Children who had not used medications that could affect pain perception, including antibiotics or analgesics.
  • Written informed consent obtained from the parents or legal guardians.

Exclusion Criteria:

  • Previous dental treatment experience.
  • Previous local anesthesia experience.
  • Uncooperative behavior during the initial examination.
  • Presence of systemic disease.
  • Presence of mental or cognitive disability.
  • Antibiotic use within the last month.
  • Analgesic use within the last 24 hours.
  • Use of any medication that could influence pain perception.
  • Refusal of parental or legal guardian consent.

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: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Conventional Dental Injection First, Comfort-in Needle-Free Injection Second
Participants in this arm received conventional dental injection in the first treatment session and Comfort-in needle-free injection in the second treatment session. The two sessions were performed on contralateral primary first molars requiring pulpotomy, with a minimum interval of one week between sessions.
Device: Comfort-in Needle-Free Injection System
The Comfort-in needle-free injection system was used to administer local anesthetic solution without needle penetration. After drying the injection site and applying topical anesthetic spray for 60 seconds, articaine hydrochloride with epinephrine 1:100,000 was administered using the Comfort-in system before pulpotomy treatment of the primary first molar.
Procedure: Conventional Dental Injection
Conventional local anesthesia was administered using a dental injector. After drying the injection site and applying topical anesthetic spray for 60 seconds, articaine hydrochloride with epinephrine 1:100,000 was administered using a 27-gauge dental injector before pulpotomy treatment of the primary first molar.
Experimental: Comfort-in Needle-Free Injection First, Conventional Dental Injection Second
Participants in this arm received Comfort-in needle-free injection in the first treatment session and conventional dental injection in the second treatment session. The two sessions were performed on contralateral primary first molars requiring pulpotomy, with a minimum interval of one week between sessions.
Device: Comfort-in Needle-Free Injection System
The Comfort-in needle-free injection system was used to administer local anesthetic solution without needle penetration. After drying the injection site and applying topical anesthetic spray for 60 seconds, articaine hydrochloride with epinephrine 1:100,000 was administered using the Comfort-in system before pulpotomy treatment of the primary first molar.
Procedure: Conventional Dental Injection
Conventional local anesthesia was administered using a dental injector. After drying the injection site and applying topical anesthetic spray for 60 seconds, articaine hydrochloride with epinephrine 1:100,000 was administered using a 27-gauge dental injector before pulpotomy treatment of the primary first molar.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pain during local anesthesia administration assessed by the FLACC scale
Time Frame: Periprocedural at Visit 1 and Visit 2, during local anesthesia administration; visits were separated by at least 1 week.
Pain-related behavior during local anesthesia administration was assessed using the Face, Legs, Activity, Cry, Consolability (FLACC) scale. The FLACC scale evaluates five behavioral categories: face, legs, activity, cry, and consolability. The total score ranges from 0 to 10, with higher scores indicating greater pain.
Periprocedural at Visit 1 and Visit 2, during local anesthesia administration; visits were separated by at least 1 week.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pain during local anesthesia and pulpotomy assessed by the Wong-Baker FACES Pain Rating Scale
Time Frame: Immediately after local anesthesia administration and immediately after pulpotomy in each treatment session
Self-reported pain was assessed using the Wong-Baker FACES Pain Rating Scale. Scores range from 0 to 10, with higher scores indicating greater pain. Pain scores were recorded after local anesthesia administration and after pulpotomy treatment for both anesthesia techniques.
Immediately after local anesthesia administration and immediately after pulpotomy in each treatment session
Pain during pulpotomy procedure steps assessed by the FLACC scale
Time Frame: Periprocedural at Visit 1 and Visit 2, during prespecified pulpotomy procedure steps.
Pain-related behavior during pulpotomy was assessed using the FLACC scale at different procedural steps, including high-speed instrumentation, low-speed instrumentation, pulp removal, matrix-wedge placement, and restoration. The total FLACC score ranges from 0 to 10, with higher scores indicating greater pain.
Periprocedural at Visit 1 and Visit 2, during prespecified pulpotomy procedure steps.
Systolic blood pressure
Time Frame: Immediately before anesthesia, immediately after anesthesia, and immediately after pulpotomy in each treatment session
Systolic blood pressure was recorded as a physiological parameter to evaluate the response to the anesthesia technique and dental treatment.
Immediately before anesthesia, immediately after anesthesia, and immediately after pulpotomy in each treatment session
Diastolic blood pressure
Time Frame: Immediately before anesthesia, immediately after anesthesia, and immediately after pulpotomy in each treatment session
Diastolic blood pressure was recorded as a physiological parameter to evaluate the response to the anesthesia technique and dental treatment.
Immediately before anesthesia, immediately after anesthesia, and immediately after pulpotomy in each treatment session
Pulse rate
Time Frame: Immediately before anesthesia, immediately after anesthesia, and immediately after pulpotomy in each treatment session
Pulse rate was recorded as a physiological parameter to evaluate the response to the anesthesia technique and dental treatment.
Immediately before anesthesia, immediately after anesthesia, and immediately after pulpotomy in each treatment session
Oxygen saturation
Time Frame: Immediately before anesthesia, immediately after anesthesia, and immediately after pulpotomy in each treatment session
Oxygen saturation was recorded as a physiological parameter during the dental treatment session.
Immediately before anesthesia, immediately after anesthesia, and immediately after pulpotomy in each treatment session
Total amount of anesthetic solution used
Time Frame: Periprocedural at Visit 1 and Visit 2, during local anesthesia administration.
The total volume of local anesthetic solution used for each anesthesia technique was recorded in milliliters.
Periprocedural at Visit 1 and Visit 2, during local anesthesia administration.
Duration of anesthetic effect
Time Frame: Immediately after local anesthesia administration in each treatment session
The duration of anesthetic effect after local anesthesia administration was recorded in hours for each anesthesia technique.
Immediately after local anesthesia administration in each treatment session
Postoperative complications after local anesthesia
Time Frame: Up to 24 hours after Visit 1 and Visit 2
Postoperative complications after local anesthesia were recorded for each anesthesia technique. Complications included lip biting, swelling, hematoma, and pain.
Up to 24 hours after Visit 1 and Visit 2
Number of Participants Preferring Each Anesthesia Technique Assessed by a Direct Preference Question
Time Frame: At completion of Visit 2
After experiencing both anesthesia techniques, participants were asked which technique they preferred: conventional dental injection or Comfort-in needle-free injection. Data were reported as the number of participants preferring each anesthesia technique.
At completion of Visit 2

Collaborators and Investigators

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

Sponsor

Ondokuz Mayıs University

Investigators

  • Principal Investigator: Sema Aydinoglu, DDS, PhD, Recep Tayyip Erdoğan University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

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)

January 1, 2019

Primary Completion (Actual)

December 31, 2021

Study Completion (Actual)

December 31, 2021

Study Registration Dates

First Submitted

April 30, 2026

First Submitted That Met QC Criteria

May 6, 2026

First Posted (Actual)

May 14, 2026

Study Record Updates

Last Update Posted (Actual)

May 14, 2026

Last Update Submitted That Met QC Criteria

May 6, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RTEU_2019/05

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared because the study included pediatric participants and specific consent for external sharing of individual participant-level data was not obtained. Aggregate study results will be reported in the manuscript.

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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