Case Reports and Reviews: Open Access

Background: Oral mucositis (OM) is a painful, dose-limiting toxicity of cytotoxic chemotherapy. It impairs nutrition and quality of life, raises infection risk and can force dose reductions or treatment delays. Photobiomodulation (PBM), the application of low-power red or near-infrared light to tissue, has emerged as the most extensively studied non-pharmacological intervention for OM. 

Objective: To summarize current evidence on PBM delivered before and during chemotherapy (preventive use) and after OM onset (therapeutic use), with emphasis on clinical protocols relevant to dental practitioners. 

Findings: The 2019/2020 Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO) guidelines recommend intraoral PBM for OM prevention in adults receiving hematopoietic stem cell transplantation (HSCT) conditioned with high-dose chemotherapy (level of evidence I), but found the evidence insufficient for a guideline in conventional-dose chemotherapy or for treating established OM. Subsequent systematic reviews and randomized trials, including pediatric trials with methotrexate-based regimens, report lower OM incidence and severity with preventive PBM, and faster healing with less pain when PBM is applied after onset. Adverse events are rare and mild. Heterogeneous dosimetry, small samples and incomplete blinding remain the main limitations. 

Conclusion: PBM is a safe, well-tolerated adjunct to basic oral care. It is best started at or before the first day of chemotherapy and continued, or resumed, once lesions appear. Standardized, adequately powered trials in conventional-dose chemotherapy are needed to extend formal guideline support.

Keywords: Oral mucositis; Photobiomodulation; Low-level laser therapy; Chemotherapy; Supportive care; Stomatitis.