Can low-power laser treatment or gentle electrical nerve stimulation reduce pain after orthodontic wires are fitted?

INTERVENTION: After confirmation of eligibility and written informed consent, 81 participants were randomly allocated in a 1:1:1 ratio to three intervention sequences using sex‐stratified, computer‐generated permuted blocks and sequentially numbered, opaque, sealed envelopes. All participants received 0.018 × 0.025‐inch fixed metal brackets. During period 1 (week 1), immediately after placement of a 0.016‐inch round nickel–titanium archwire, Group A received active low‐level laser therapy (LLLT), Group B received active transcutaneous electrical nerve stimulation (TENS), and Group C received sham LLLT. During period 2 (week 5), immediately after placement of a 0.016 × 0.016‐inch rectangular nickel–titanium archwire, Group A received active TENS, Group B received active LLLT, and Group C received sham TENS. LLLT was delivered using a Solase diode laser (Lazon Laser, Shenyang, China) at 976 nm and 0.5 W in continuous mode through a 1 cm² biostimulation tip. Treatment was applied for 15 seconds per tooth (7.5 J per point; 7.5 J/cm²) at one vestibular point corresponding to the middle third of each root, with the tip in contact with the gingival mucosa. TENS was delivered using a Medelsan device (Istanbul, Türkiye) with a 200‐µs pulse width at 50 Hz for 20 minutes. Extraoral 5 × 5 cm electrodes were positioned near the premolar roots immediately below the zygomatic bone for the maxilla and near the mental foramen for the mandible. Participant‐specific stimulation amplitudes were not retained. The right side was the fixed application side and the left side was the untreated contralateral comparator. Sham LLLT used the same device placement and application procedure without laser emission. Sham TENS used the same electrode placement and duration without electrical current. Pain was recorded separately for the application and contralateral sides for 48 hours after each intervention period. CONDITION: Pain following fixed orthodontic archwire placement in adolescents and young adults with mild dental crowding. ; Oral Health PRIMARY OUTCOME: Orthodontic pain intensity for the right application side and the left contralateral side measured using self‐reported 0–100 visual analogue scale (VAS), where 0 indicated no pain and 100 indicated the worst pain imaginable at 0, 2, 4, 6, 12, 24 and 48 hours after the intervention following archwire placement in each study period (week 1 and week 5). The retained protocol materials did not identify a single primary timepoint; all prespecified VAS timepoints are therefore listed. SECONDARY OUTCOME: Adverse events associated with LLLT and TENS measured using occurrence and type of any discomfort or unintended event documented in treatment and follow‐up records at during each device application and throughout the 48‐hour follow‐up period after each intervention session at weeks 1 and 5 INCLUSION CRITERIA: 1. Male or female participants aged 14–20 years 2. Permanent dentition 3. Dental crowding of 2–4 mm in both the maxillary and mandibular arches 4. No previous orthodontic treatment