Low-level laser or LED photobiomodulation on oral mucositis in pediatric patients under high doses of methotrexate: prospective, randomized, controlled trial.

PURPOSE: The objective of the present study was to compare the efficacy of photobiomodulation with low-level laser therapy (LLLT) or light-emitting diode therapy (LEDT) devices for the prevention and treatment of oral mucositis in pediatric patients diagnosed with acute lymphoblastic leukemia undergoing chemotherapy with high doses of methotrexate (MTX). METHODS: Eighty patients were randomly divided into two groups: LLLT and LEDT. Both protocols were applied with the same energy and radiant exposure. The protocols started in the beginning of high doses MTX and finished when the patients were discharged from the hospital or there was oral mucositis resolution. The oral mucositis was assessed during each session in accordance to the World Health Organization (WHO) score. The patients' self-assessed pain was scored on a visual analog scale (VAS). RESULTS: The incidence of oral mucositis was similar to LLLT and LEDT, 10% and 12.5%, respectively. Both groups required the same number of days to reach score of zero for mucositis and pain (p > 0. 05), and there was no significant difference in mean VAS between the groups. CONCLUSIONS: These findings suggest that LEDT has similar effects to LLLT to avoid and treat oral mucositis. Brazilian Clinical Trial Registry with #U1111-1221-5943.

Photobiomodulation is associated with a decrease in cell viability and migration in oral squamous cell carcinoma.

The treatment of squamous cell carcinoma (SCC) involves surgery, chemotherapy, and/or radiotherapy, which can cause mucositis (inflammation of the oral mucosa that causes considerable pain and can compromise the continuity of oncological treatment). Photobiomodulation (PBM) has been successfully used in the treatment of mucositis, but doubts arise regarding the use of laser for areas in which tumor cells may remain. In this study, the effect of PBM on the viability, mitochondrial activity, proliferation, apoptosis, and migration of cells derived from oral SCC was evaluated. SCC9 cells were irradiated with laser (660 and 780 nm, using 11 dosimetric parameters) and submitted to mitochondrial and caspase 3 activity tests after 1 and 3 days. Based on the results, cell viability (neutral red assay), proliferation (BrdU assay), and migration (scratch-wound assay) were evaluated using only the dosimetric parameters recommended for mucositis. Non-irradiated cells served as the control. The experiments were performed in triplicate. The 11 parameters diminished mitochondrial activity and induced tumor cell apoptosis. Using the parameters recommended for mucositis, irradiation with 780 nm (70 mW, 4 J/cm2) proved to be the safest and led to a reduction in cell viability, the induction of apoptosis, and a reduction in the migration capacity of the tumor cells.

Effect of low-intensity laser treatment on pain after extraction of impacted mandibular third molars: a randomised, controlled, clinical trial.

Extraction of impacted third molars is painful, so we have evaluated whether low-intensity laser could reduce the pain. Sixty patients were randomly allocated to five groups that were treated with laser immediately after extraction. Postoperative pain was evaluated after two and seven days. The Shapiro-Wilk test was used to assess whether the distribution was normal, and as it was skewed, the Kruskal-Wallis test, ANOVA and the Student-Newman-Keuls test for multiple comparisons were used to compare the groups. The Wilcoxon test was used for comparisons of pain (measured by visual analogue scale (VAS) and numerical rating scale (NRS) 101 between the second and seventh postoperative days). Probabilities of less than 0.05 were accepted as significant. We conclude that a single session of low intensity laser had no significant effect on the amount of pain under the conditions investigated.

Measurement of effective remnant power in low intensity laser after passage through the buccinator muscle in anatomical human hemifaces / Determinação da potência efetiva remanescente após a passagem do laser de baixa intensidade através do músculo bucinador em peças anatômicas/hemifaces

Objective: To determine the effective remnant power after the passage of low intensity laser of two different wavelengths (660 and 780 nm) through buccinator muscle in anatomical hemifaces. Methods: Five human hemifaces were dissected, and a laser was shone in the central region of the muscle with a receiver placed on the opposite side. The hemifaces were irradiated using the same dosimetric parameters (40 mW, 1 W/cm2, continuous mode, 0.04 cm2) and at the same point in every muscle; remnant power was measured for each irradiation. Results: The average remnant power after irradiation with 660 nm (149 ± 15 µW) light was significantly lower (p<0.0001) than with that of 780 nm (380 ± 40 µW). Conclusion: The LIL of 780 nm presented greater remnant power in comparison to the 660 nm laser after passage through the buccinator muscle, indicating the latter ́s greater penetration capacity.

Objetivo: Determinar a potência remanescente após a passagem do laser de baixa intensidade em dois comprimentos de onda (660 e 780 nm) através do músculo bucinador em peças anatômicas dissecadas. Métodos: Dissecaram-se cinco hemifaces humanas expondo o músculo bucinador. Aplicou-se o laser na região central de cada músculo, e o receptor, para aferir a potência remanescente, foi posicionado na superfície intraoral contrária. As hemifaces foram irradiadas nos mesmos parâmetros dosimétricos (40 mW, 1 W/cm2, modo contínuo, 0,04 cm2) e no mesmo ponto em cada músculo, sendo a potência remanescente aferida a cada repetição. Resultados: A potência média restante após as irradiações de 660 nm (149 ± 15 µW) foi menor (p <0,0001) que com as irradiações de 780 nm (380 ± 40 µW). Conclusão: O LBI de 780 nm apresentou maior potência remanescente que o LBI de 660 nm, após passagem pelo músculo bucinador, denotando sua maior capacidade de penetração.