Topical Cryoanesthesia Versus Benzocaine in Pediatric Dentistry (No acronym)

January 9, 2026 updated by: José Arturo Garrocho Rangel, Universidad Autonoma de San Luis Potosí

Comparison of Topical Cryoanethesia and Benzocaine in Pain Perception During Mandibular Nerve Block in Pediatric Patients: A Randomized Controlled Clinical Trial

This clinical study tested and compared two ways (cold-base technique or "cryoanesthesia" and conventional benzocaine gel) to reduce pain from dental injections in children.

Researchers worked with 28 children between 6 and 12 years old who needed injections on both sides of the lower jaw for dental treatment. Each child received cryoanesthesia on one side and 20% benzocaine gel on the other side, in different appointments, and the team measured pain, behavior, heart rate, and blood oxygen levels.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Objective: To evaluate and compare pain perception during inferior alveolar nerve block puncture in pediatric patients using cryoanesthesia versus conventional topical benzocaine anesthesia.

Methods: A split-mouth randomized controlled clinical trial was conducted with 28 patients aged 6 to 12 years requiring bilateral inferior alveolar nerve blocks for bilateral lower arch dental treatment. Each participant received both anesthetic techniques in a randomized order on separate appointments, with treatment allocated to contralateral mandibular hemiarches. Primary and secondary outcome measures included pain intensity (Visual Analog Scale), heart rate, oxygen saturation, and behavioral response (FLACC scale).

Study Type

Interventional

Enrollment (Actual)

28

Phase

  • Phase 3

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

  • Mexico
    • S.l.p.
      • San Luis Potosí City, S.l.p., Mexico, 78990
        • Pediatric Dentistry Postgraduate Program, Faculty of Denttistry

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

Yes

Description

Inclusion Criteria:

  • Systemic health: No significant medical history or uncontrolled systemic disease.
  • Bilateral dental pathology requiring treatment: At least two teeth (one per mandibular hemiarch) requiring bilateral inferior alveolar nerve blocks for restorative or endodontic treatment.
  • Cooperation level: Frankl behavioral rating scale classification III or IV (positive or very positive).
  • Informed consent/Child assent: Signed informed consent from parent or legal guardian; signed assent from participant (age-appropriate).

Exclusion Criteria:

  • Acute dental emergency requiring immediate treatment.
  • Known hypersensitivity or allergy to benzocaine or other local anesthetics.
  • Known hypersensitivity to cold (cryophobia or cold urticaria).
  • Significant dental anxiety or phobia precluding study participation.
  • Developmental delay or behavioral disorders limiting communication or cooperation.
  • Current use of medications affecting pain perception or hemodynamic parameters.

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
Intervention / Treatment
Experimental: Cryanesthesia. Topical anesthesia using application of ice cones, before anesthesic punction.

Ice cones were prepared using sterile, individual-sized latex gloves filled with purified, sterile water. The open end of each glove was sealed and the glove was placed in a freezer (temperature: -18°C to -20°C) for minimum 24 hours prior to use. This produced a textured ice cone of approximately 5 cm × 3 cm suitable for direct application to the infiltration site.

  1. The application site (infiltration area on mucous membrane) was gently dried with sterile gauze.
  2. The ice cone was applied directly to the area using gentle circular rubbing motions.
  3. Duration of application: 60 seconds.
  4. Assessment: Observation for tissue blanching (white appearance) indicating adequate cooling.
Procedure: Local Anesthesia (lidocaine hydrochloride)

After topical anesthesia (either technique), the clinician proceeded with conventional inferior alveolar nerve block using standardized technique:

  1. Patient positioned recumbent in dental chair with mouth held open.
  2. Palpation of ipsilateral mandibular condyle by clinician's non-dominant hand.
  3. Cheek retracted with non-dominant hand to improve visualization.
  4. Long needle (27-gauge, 32 mm) inserted at horizontal level of contralateral mandibular canine, directed toward insertion of lateral pterygoid muscle below maxillary tuberosity.
  5. Needle advanced to contact medial mandibular wall (lingual surface).
  6. Aspiration performed to rule out intravascular needle placement.
  7. Injection of local anesthetic solution (1.8 mL of 2% lidocaine with 1:100,000 epinephrine).
  8. Needle carefully withdrawn following injection completion.
Procedure: Local Anesthesia (lidocaine hydrochloride)

After topical anesthesia (either technique), the clinician proceeded with conventional inferior alveolar nerve block using standardized technique:

  1. Patient positioned recumbent in dental chair with mouth held open
  2. Palpation of ipsilateral mandibular condyle by clinician's non-dominant hand
  3. Cheek retracted with non-dominant hand to improve visualization
  4. Long needle (27-gauge, 32 mm) inserted at horizontal level of contralateral mandibular canine, directed toward insertion of lateral pterygoid muscle below maxillary tuberosity
  5. Needle advanced to contact medial mandibular wall (lingual surface)
  6. Aspiration performed to rule out intravascular needle placement
  7. Injection of local anesthetic solution (1.8 mL of 2% lidocaine with 1:100,000 epinephrine)
  8. Needle carefully withdrawn following injection completion
Active Comparator: Benzocaine group: Topical anesthesia using 20% benzocaine, before anesthetic punction.

Benzocaine 20% Topical Anesthesia Technique:

  1. The application site was gently dried with sterile gauze
  2. Benzocaine 20% topical solution was applied using a sterile cotton applicator via gentle rubbing of the infiltration site
  3. Duration of application: 60 seconds
  4. No mechanical removal was performed; anesthetic was allowed to remain on tissue
Procedure: Local Anesthesia (lidocaine hydrochloride)

After topical anesthesia (either technique), the clinician proceeded with conventional inferior alveolar nerve block using standardized technique:

  1. Patient positioned recumbent in dental chair with mouth held open.
  2. Palpation of ipsilateral mandibular condyle by clinician's non-dominant hand.
  3. Cheek retracted with non-dominant hand to improve visualization.
  4. Long needle (27-gauge, 32 mm) inserted at horizontal level of contralateral mandibular canine, directed toward insertion of lateral pterygoid muscle below maxillary tuberosity.
  5. Needle advanced to contact medial mandibular wall (lingual surface).
  6. Aspiration performed to rule out intravascular needle placement.
  7. Injection of local anesthetic solution (1.8 mL of 2% lidocaine with 1:100,000 epinephrine).
  8. Needle carefully withdrawn following injection completion.
Procedure: Local Anesthesia (lidocaine hydrochloride)

After topical anesthesia (either technique), the clinician proceeded with conventional inferior alveolar nerve block using standardized technique:

  1. Patient positioned recumbent in dental chair with mouth held open
  2. Palpation of ipsilateral mandibular condyle by clinician's non-dominant hand
  3. Cheek retracted with non-dominant hand to improve visualization
  4. Long needle (27-gauge, 32 mm) inserted at horizontal level of contralateral mandibular canine, directed toward insertion of lateral pterygoid muscle below maxillary tuberosity
  5. Needle advanced to contact medial mandibular wall (lingual surface)
  6. Aspiration performed to rule out intravascular needle placement
  7. Injection of local anesthetic solution (1.8 mL of 2% lidocaine with 1:100,000 epinephrine)
  8. Needle carefully withdrawn following injection completion

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pain perception
Time Frame: Baseline: At the time of the anesthetic injection (or needle puncture) at the oral mucosa.

Pain intensity was assessed using a validated instrument:

Wong-Baker FACES® Pain Rating Scale (Visual Analog Scale): Immediately following completion of infiltration anesthesia injection, the participant was asked to indicate the level of pain experienced using the face scale (0 = no hurt to 10 = hurts worst).
Baseline: At the time of the anesthetic injection (or needle puncture) at the oral mucosa.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Heart Rate
Time Frame: Periprocedural: During the injection anesthetic procedure, from the anesthetic solution injection to the removal of the needle (approximately 45 seconds)

Continuous pulse oximetry monitoring was conducted using a calibrated pulse oximeter (typical brands: Nellcor or equivalent) with appropriate pediatric finger probe or reusable sensor. Measurement unit: Pulses per minute (ppm) for heart rate (HR), which were recorded at two time points:

  1. Baseline measurement: Immediately before topical anesthetic application, with the participant in a calm resting state.
  2. During anesthetic infiltration: Recorded during active injection of local anesthetic solution into the infiltration site (oral mucosa).
Periprocedural: During the injection anesthetic procedure, from the anesthetic solution injection to the removal of the needle (approximately 45 seconds)
Oxygen saturation
Time Frame: Periprocedural: During the injection anesthetic procedure, from the needle puncture to the removal of the needle (approximately 45 seconds).
Percentage of blood's hemoglobin carrying oxygen (normally 95-100%). Continuous pulse oximetry monitoring was conducted using a calibrated pulse oximeter (typical brands: Nellcor or equivalent) with appropriate pediatric finger probe or reusable sensor. Measurement units: SpO2 percentage (%), which was recorded at two time points: 1. Baseline measurement: Immediately before topical anesthetic application, with the participant in a calm resting state. And 2. During infiltration measurement: During active injection of local anesthetic solution into the infiltration site.
Periprocedural: During the injection anesthetic procedure, from the needle puncture to the removal of the needle (approximately 45 seconds).
Patient's behavioral response
Time Frame: Periprocedural: 45 seconds, from the anesthetic injection to the removal of the needle.
Observable emotional and physiological reactions to the anesthetic injection through the FLACC (Facial expression, Legs, Activity, Cry, and Consolability) scale. Values: 0-10 (0 = relaxed, calm; 10 = severe distress).
Periprocedural: 45 seconds, from the anesthetic injection to the removal of the needle.

Collaborators and Investigators

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

Sponsor

Universidad Autonoma de San Luis Potosí

Investigators

  • Study Director: Amaury Pozos Guillén, Ph.D., Universidad Autonoma de San Luis Potosí

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)

June 15, 2025

Primary Completion (Actual)

October 10, 2025

Study Completion (Actual)

November 25, 2025

Study Registration Dates

First Submitted

November 27, 2025

First Submitted That Met QC Criteria

January 9, 2026

First Posted (Actual)

January 20, 2026

Study Record Updates

Last Update Posted (Actual)

January 20, 2026

Last Update Submitted That Met QC Criteria

January 9, 2026

Last Verified

December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • U.A.S.L.P.
  • No funding (Other Identifier: No issuing organization)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

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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