Patient-reported outcome measures of accelerated upper canine retraction with low-amperage electrical stimulation: A randomized controlled trial

Background

Interest in accelerating orthodontic tooth movement has been increasing, with a particular focus on methods that prioritize high-quality patient-reported outcomes. Among these, low-amperage electrical stimulation (LAES) emerges as a promising technique. However, the patient-reported outcome measures related to its intraoral application remain largely unexplored.

Objectives

This randomized controlled trial evaluated the clinical tolerance and patient-reported outcomes of an intraoral LAES device during maxillary canine retraction. Pain perception during the early phase (A1–A3) was designated as the primary outcome. Secondary outcomes included discomfort, swallowing, chewing, and speech difficulties, analgesic use, overall satisfaction, and willingness to recommend the procedure.

Methods and Trial design

A two-arm randomized controlled clinical trial with a 3-month follow-up. Thirty-six adults (17–28 years) with Class II Division 1 malocclusion requiring bilateral maxillary first premolar extraction were randomized to LAES (n = 18) or control (n = 18). Patient-reported outcomes were recorded at nine time points (A1–C3). Pain (primary outcome) was analysed using a linear mixed-effects model, with clinical significance defined a priori as ±20 mm on the 100-mm VAS. Equivalence was assessed using the two one-sided tests procedure with 90% confidence intervals. Secondary outcomes were summarized descriptively with between-group mean differences and 90%/95% CIs.

Results

Pain scores were lower in the LAES group at several early assessments (notably A1–A3), but between-group differences did not exceed the ±20 mm clinical threshold. Equivalence was not confirmed at A1 and A2 but was supported from A3 onward. Discomfort was greater in the LAES group during initial intervals, with confidence intervals exceeding the equivalence margin, indicating clinically relevant short-term limitations. Swallowing and chewing difficulties remained mild and clinically negligible. Speech difficulty was significantly higher in the LAES group during the first week but declined thereafter, consistent with adaptation. Analgesic intake was minimal in both groups. Despite these transient drawbacks, satisfaction was high, and all participants indicated willingness to recommend the procedure.

Harms

No systemic adverse events occurred during the trial; one patient experienced palatal abrasion that resolved without sequelae.

Conclusions

The LAES device was safe and generally well tolerated. While it did not provide clinically meaningful reductions in pain, it was associated with greater early discomfort and speech difficulty, both of which diminished with continued use. Patient satisfaction remained high, suggesting good overall acceptability. Larger, longer-term trials with device refinements to reduce palatal bulk and incorporate objective compliance monitoring are warranted before widespread clinical adoption.

Trial registration

The protocol was registered in the Clinical Trials database (NCT06875037).