Reducing Pain During Dental Nerve Block Injections in Children

Study Design This is a prospective, parallel-group, randomized controlled clinical trial (RCT) conducted at the Department of Pediatric Dentistry, Al-Mustansiriyah University College of Dentistry, Baghdad, Iraq. The trial is designed to compare the effectiveness of three interventions versus a standard control in reducing pain, physiological stress, and behavioral distress during inferior alveolar nerve block (IANB) in pediatric dental patients. Participants A total of 166 medically healthy children (ASA I or II) aged 5 to 9 years, who required dental treatment under IANB, were enrolled. Inclusion criteria included a baseline Frankl Behavior Rating of 2 or 3 (cooperative or potentially cooperative). Exclusion criteria were systemic illness, neurological or developmental conditions affecting pain perception, previous traumatic dental injection experience, allergy to lidocaine or epinephrine, and significant respiratory or cardiovascular conditions. Randomization and Allocation Children were randomly assigned to one of four groups using a sealed-envelope method to ensure allocation concealment. Group sizes: Cooling + Vibration (n=40), Counterstimulation (n=41), 30-gauge needle (n=43), and standard 27-gauge needle control (n=42). Interventions All injections use 2% lidocaine with 1:100,000 epinephrine, administered at a controlled rate of 1 mL/min by calibrated pediatric dentists. Cooling + Vibration group: A thermomechanical device (Buzzy®, MMJ Labs, USA) is applied externally to the injection site for 30-60 seconds before needle insertion and remains in place during anesthetic deposition. The device provides simultaneous cooling and vibration. Counterstimulation group: Gentle manual tapping or pressure with a cotton roll is applied adjacent to the injection site throughout the procedure. 30-gauge needle group: IANB is performed using a long 30-gauge needle without any distraction technique. Standard control group (27-gauge needle): Routine IANB using a long 27-gauge needle, representing standard clinical practice. Outcome Measures Primary outcomes: Child self-reported pain using the Wong-Baker FACES Pain Rating Scale (0-10) immediately post-injection. Observer-rated pain behavior using the FLACC scale (Face, Legs, Activity, Cry, Consolability; 0-10) during the injection. Secondary outcomes: Heart rate (beats per minute) and oxygen saturation (%) continuously recorded via pediatric pulse oximetry. Behavioral cooperation assessed with the Frankl Behavior Rating Scale (1-4). All outcome assessments are performed by a blinded, calibrated observer. Children provide self-reported pain scores immediately after the injection using age-appropriate instructions. Statistical Analysis Descriptive statistics will summarize baseline characteristics. Paired t-tests will compare within-group changes from baseline to follow-up. One-way analysis of variance (ANOVA) with Bonferroni post-hoc corrections will be used for between-group comparisons. The level of statistical significance is set at p \< 0.05. Analyses will be performed using IBM SPSS version 28. Ethical Approval The study protocol was approved by the Institutional Review Board of Al-Mustansiriyah University College of Dentistry (clinical trial number: MUPEDO4, REC199). Written informed consent was obtained from parents or legal guardians, and assent was obtained from children. The study complies with the Declaration of Helsinki (2013). Children who become excessively distressed are withdrawn and managed according to standard care. Trial Registration (If applicable, the registry number and date would be entered here; the document lists an internal number MUPEDO4, REC199.