Comparative Effects of Low-Level Laser Therapy and Transcutaneous Electrical Nerve Stimulation on Neurosensory Recovery After Trigeminal Nerve Injury: An Exploratory Non-Randomized Clinical Study

Objective: Inferior alveolar (IAN) and lingual nerve (LN) injuries are known complications of impacted mandibular third molar surgery and may result in persistent neurosensory deficits. This exploratory, non-randomized clinical study evaluated the clinical and electrophysiological effects of low-level laser therapy (LLLT) and transcutaneous electrical nerve stimulation (TENS) on neurosensory recovery following trigeminal nerve injury. Methods: Twenty-seven patients with postoperative IAN or LN injury received LLLT, TENS, or placebo therapy according to institutional clinical protocols. Clinical outcomes were assessed using Visual Analog Scale (VAS) scores, and electrophysiological evaluation was performed using electromyography by measuring cutaneous silent period (CSP) duration. Non-parametric statistical analyses were conducted using the Wilcoxon signed-rank and Mann-Whitney U tests. Results: LLLT was associated with statistically significant improvements in several neurosensory symptoms, including pain, burning sensation, speech difficulty, biting, and taste disturbance. In contrast, TENS and placebo treatment did not demonstrate a consistent or generalized improvement across neurosensory outcomes. CSP durations differed significantly between healthy and pathological sides both before and after treatment. Although CSP duration showed a tendency to increase following LLLT, these changes did not reach statistical significance. Subgroup analysis revealed greater clinical improvement in LN injuries compared with IAN injuries within the LLLT group. Conclusions: Within the limitations of this exploratory study, LLLT was associated with more pronounced clinical improvement than TENS or placebo in patients with third molar-related trigeminal nerve injury. CSP measurements provided supportive objective information, although electrophysiological recovery remained limited.