Effectiveness of Needle-Free Infiltration Anesthesia in Reduction of Dental Pain and Anxiety During Local Anesthesia.

Evaluation of the Effectiveness of Needle-Free Infiltration Anesthesia in Alleviating Dental Pain and Anxiety Among Children During Local Anesthesia. Randomized Controlled Trial

Local anesthesia is a common and essential procedure for the majority of dental treatments. The most frequently used method of administration is needle injection. Although this technique effectively controls pain, the sight of the needle and the pain experienced during injection often cause fear and anxiety, especially in children. This can lead to negative attitudes toward dental treatment, highlighting the need for less painful alternatives for delivering local anesthesia.

This randomized clinical trial aimed to evaluate the effectiveness of the needle-free INJEX 30 device in reducing pain and anxiety in children aged 6 to 9 years.

Eligible children requiring local anesthesia in the mandibular primary molar region for therapeutic dental procedures were randomly assigned to two groups according to the type of injection system used (INJEX or conventional syringe).

Immediately after the administration of local anesthesia, anxiety was assessed using a physiological measure (plus rate), and pain was evaluated using a self-reported scale (Wong-Baker Faces Pain Scale). Pain was also assessed using a non-self-reported behavioral scale (FLACC) based on video recordings taken during anesthesia administration.

The findings of this study provide clinical evidence about the effectiveness of the INJEX device in reducing pain and anxiety during local anesthesia in pediatric dental patients, which thereby improving clinical decision-making and enhancing the quality of dental care for children.

Study Overview

• Status: Completed
• Conditions: This Study Aims to Evaluate the Effectiveness of the INJEX Device in Administering Local Anesthesia
• Intervention / Treatment: Device: INJEX 30; Procedure: Traditional syringe

Detailed Description

Local anesthesia is a cornerstone of pediatric dental treatment, allowing clinicians to perform restorative and preventive procedures while minimizing pain and discomfort. Nevertheless, administering local anesthesia in children presents several challenges. Achieving profound anesthesia can be difficult in some cases due to anatomical variations, while the risk of local anesthetic toxicity is increased because of the child's lower body weight. Most importantly, fear of needles and pain during injection often provoke anxiety and unpredictable behavioral responses, which can complicate dental treatment and negatively affect the child's overall experience.

The inferior alveolar nerve block is commonly used for pulp therapy of lower primary molars, as it provides relatively deep and long-lasting anesthesia. However, this technique is associated with several disadvantages, including a higher risk of soft tissue injury, prolonged numbness, and greater discomfort during injection. Additionally, inferior alveolar nerve block injections are generally perceived as more painful than infiltration anesthesia techniques, particularly in pediatric patients.

Despite the effectiveness of conventional nerve block techniques, their limitations in children highlight the need for alternative anesthesia methods that are less painful while maintaining adequate anesthetic efficacy. Therefore, a different anesthetic approach with a shorter duration but comparable effectiveness was considered. For this purpose, a needle-free, pressure-based injection system was used in the present study.

Needleless injection devices, such as the INJEX system, deliver local anesthetic solutions into the tissues using high pressure, eliminating the need for conventional needles.

This study aimed to evaluate and compared the effectiveness of the INJEX device and the conventional syringe technique in administering local anesthesia for lower primary molars, with a particular focus on pain perception and anxiety reduction. Both subjective pain assessment scales and objective physiological and behavioral measures were employed to provide a comprehensive evaluation. By identifying anesthetic techniques that reduce pain and anxiety while maintaining clinical effectiveness, this research seeked to improve the quality of pediatric dental care and promote more positive dental experiences for children

• Study Type: Interventional
• Enrollment (Actual): 52
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Syria
  • Rif-dimashq Governorate
    • Damascus, Rif-dimashq Governorate, Syria
      • Department of Pediatric Dentistry, Faculty of Dentistry

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Children aged 6-9 years with no previous dental experience.
2. Children classified as positive or definitely positive according to the Frankl behavior rating scale.
3. Children requiring local anesthesia in the lower primary molar region for therapeutic dental procedures

Exclusion Criteria:

1. Children with systemic diseases that contraindicate the administration of local anesthesia or the required dental treatment.

2. Children who have received sedative or analgesic medications within the 3 hours preceding the dental visit

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Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 0.3 ml of lidocaine using injex: In the first group, 0.3 mL of lidocaine will be administer	Device: INJEX 30; Participants were randomly assigned using the website (www.randomization.com), and based on the generated random numbers, each child was allocated to the corresponding study group. The dental procedure was then explained to the child using the "Tell-Show-Do" technique. A topical anesthetic gel (20% benzocaine) was applied at the injection site before administering local anesthesia.; group: 0.3 ml of lidocaine using injex: In the first group, 0.3 mL of lidocaine will be administered locally by infiltration using the INJEX 30 device.; group :1.8 ml of lidocaine using Traditional syringe: In the second group (control group), 1.8 mL of lidocaine will be administered using a conventional syringe as an inferior alveolar nerve block.
Active Comparator: 1.8 ml of lidocaine using Traditional syringe: In the second group (control group), 1.8 mL of lidoc	Procedure: Traditional syringe; After obtaining the general medical history of each child, comprehensive clinical and radiographic examinations were performed to assess the feasibility of performing dental procedures in the lower primary molar region under local anesthesia. Written informed consent was obtained from the parents or legal guardians for both the dental procedure and the child's participation in the study. Participants were randomly assigned using the website (www.randomization.com), and based on the generated random numbers, each child was allocated to the corresponding study group. Prior to the procedure, the child's pulse was measured using a physiological monitor (Plus Oximeter). The dental procedure was then explained to the child using the "Tell-Show-Do" technique. A topical anesthetic gel (20% benzocaine) was applied at the injection site before administering local anesthesia. In this group, serving as the control, local anesthesia was administered using the conventional technique (inferior alveol

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Dental Pain - FLACC Scale	Pain during local anesthesia administration will be evaluated using the FLACC behavioral observational scale (Face, Legs, Activity, Cry, Consolability). Scores range from 0-10: 0 = Relaxed 1-3 = Mild discomfort 4-6 = Moderate discomfort 7-10 = Severe discomfort Measurements will be recorded continuously during the administration of local anesthesia.	During local anesthesia administration, from insertion of the device into the oral cavity until completion of the anesthetic delivery and removal of the device.
Dental Pain - Wong-Baker Faces Scale	Pain will be self-assessed by the child using the Wong-Baker Faces Pain Rating Scale, consisting of six faces ranging from happiest (0 = no pain) to saddest (10 = severe pain). The child will be instructed to choose the face that best represents their pain immediately after local anesthesia administration.	Immediately after local anesthesia administration
Dental Anxiety - Pulse Rate	Dental anxiety will be estimated objectively by measuring pulse rate (beats per minute, bpm) using a pulse oximeter. Measurements will be taken at two time points: At baseline (pre-procedure, at set); Immediately after local anesthesia administration	Baseline and immediately after local anesthesia administration

Collaborators and Investigators

• Sponsor: Damascus University

Publications and helpful links

General Publications

• Arapostathis KN, Dabarakis NN, Coolidge T, Tsirlis A, Kotsanos N. Comparison of acceptance, preference, and efficacy between jet injection INJEX and local infiltration anesthesia in 6 to 11 year old dental patients. Anesth Prog. 2010 Spring;57(1):3-12. doi: 10.2344/0003-3006-57.1.3.
• Oliveira ACA, Amorim KS, Nascimento Junior EMD, Duarte ACB, Groppo FC, Takeshita WM, Souza LMA. Assessment of anesthetic properties and pain during needleless jet injection anesthesia: a randomized clinical trial. J Appl Oral Sci. 2019 Jan 14;27:e20180195. doi: 10.1590/1678-7757-2018-0195.
• Ocak H, Akkoyun EF, Colpak HA, Demetoglu U, Yucesoy T, Kilic E, Alkan A. Is the jet injection effective for teeth extraction? J Stomatol Oral Maxillofac Surg. 2020 Feb;121(1):19-24. doi: 10.1016/j.jormas.2019.05.001. Epub 2019 May 8.
• Kaya E, Yildirim S. Effect of a needle-free system versus traditional anesthesia on pain perception during palatal injections in children. Int J Paediatr Dent. 2023 Mar;33(2):132-140. doi: 10.1111/ipd.13028. Epub 2022 Oct 17.
• Maganur PC, Vishwanathaiah S, Jafer MA, Moafa I, Alessa N, Assiry AA, Altowairqi SA, Basheri AAM, Najmi HH, Alhazmi ZA, Maafa SM, Jeevanandan G, Manoharan V. Pain and Anxiety Levels During Dental Restorations in Primary Molars: INJEX Needleless System vs Traditional Syringe. Med Sci Monit. 2025 Apr 18;31:e947691. doi: 10.12659/MSM.947691.
• Patel M, Bhatt R, Mehta M, Patel C, Patel F, Makwani D. A comparative assessment of efficacy and preference between needleless device INJEX and insulin syringe for anesthetizing primary maxillary teeth in children aged 4-9 years: A split-mouth crossover randomized clinical study. J Indian Soc Pedod Prev Dent. 2023 Apr-Jun;41(2):149-155. doi: 10.4103/jisppd.jisppd_199_23.

Study record dates

Study Major Dates

• Study Start (Actual): May 28, 2025
• Primary Completion (Actual): November 26, 2025
• Study Completion (Actual): November 26, 2025

Study Registration Dates

• First Submitted: February 3, 2026
• First Submitted That Met QC Criteria: February 15, 2026
• First Posted (Actual): February 23, 2026

Study Record Updates

• Last Update Posted (Actual): February 23, 2026
• Last Update Submitted That Met QC Criteria: February 15, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Local anesthesia; Infiltration anesthesia; Needle-free anesthesia; Dental Pain and anxiety
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Stomatognathic Diseases; Mental Disorders; Tooth Diseases; Facial Pain; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Anxiety Disorders; Toothache
• Other Study ID Numbers: UDDS-Pedo-5-2025

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
• product manufactured in and exported from the U.S.: No