Evaluation of the Preventive Effect of Photobiomodulation on Orofacial Discomfort in Dental Procedures: A Randomized-Controlled, Crossover Study and Clinical Trial.

Background: Orofacial pain has been a prevalent symptom in the worldwide population, which may cause restrictions in daily activities and, consequently, have a great impact on the well-being of affected individuals. Photobiomodulation using light sources, such as low-level laser or light emitting diodes, with different wavelengths, has been widely used in the last years, in addition to being a noninvasive, low-cost resource and reducing pain. Objective: This study aimed at evaluating the effect of photobiomodulation as a protocol treatment to prevent facial muscle discomfort after long-term clinical procedures. Methods: The volunteers were randomized and allocated as follows: laser (n = 16) and placebo (n = 16) groups, following a crossover study design. The laser parameters were as following: 786 nm wavelength, 9 J per point, and 100 mW power of 2.393 W/cm2 irradiance. The discomfort was induced by simulating a 50-min dental procedure (with bilateral mouth open), and the pain scale (assessed bilaterally), tiredness, and temperature measurement through thermography were used for analysis. Results: The results showed a significant lower pain and tiredness in the laser group. Also, the results showed a statistically significant valid temperature change between the groups at times: T1, T40, and T50. Conclusions: According to our results, photobiomodulation showed a positive effect on the face musculature in patients submitted to the treatments, reducing pain and improving the subjective perception of exertion.

Effect of Photobiomodulation on Salivary Cortisol, Masticatory Muscle Strength, and Clinical Signs in Children with Sleep Bruxism: A Randomized Controlled Trial.

Background: The diagnosis of sleep bruxism (SB) in children is difficult due to the lack of a polysomnographic protocol for this population. Moreover, the gold standard treatment [occlusal splint (OS) therapy] has limitations, as adequate use depends on the child's cooperation. The etiology of SB may include stress factors. Salivary cortisol is a biomarker used as a noninvasive method to evaluate the response to stress. Besides physiological aspects, it is also important to investigate morphological aspects, such as masticatory muscle strength. The aim of the present study was to determine the occurrence of bite marks on the buccal mucosa in children as a complementary sign for the diagnosis of SB and investigate and the effectiveness of photobiomodulation as an alternative treatment for this condition. Methods: Seventy-six children 6-12 years of age were divided into four groups: G1-with SB and submitted to laser therapy over acupuncture points (λ = 786.94 nm, 20 sec per point, fluency = 33.5 Jcm2, energy = 1 J, number of points = 12); G2-with SB, use of OS, G3-with SB and submitted to sham laser therapy; and G4-control group without SB. Clinical signs (bite marks on buccal mucosa and headaches), bite force (BF), and salivary cortisol (biomarker of stress) were evaluated before and after treatment. Statistical analysis involved the Kolmogorov-Smirnov, Shapiro-Wilk, and analysis of variance (ANOVA) tests. Results: Bite marks on the buccal mucosa were significantly associated with SB (p < 0.001). A statistically significant difference was found between the frequency of children with headache before and after treatment in G1 (p = 0.0005) and G2 (p = 0.0001), with no significant differences between the two groups (G1 and G2). The children in G1 had lower BF on both sides compared to the other groups. In the intragroup analysis after treatment, all groups exhibited an increase in salivary cortisol levels. Conclusions: Bite marks on the buccal mucosa can be used as a complementary sign for the clinical diagnosis of SB. Children with SB responded well to photobiomodulation therapy, as evidenced by the reduction in BF and reports of headache.

Susceptibility of Streptococcus mutans biofilms to photodynamic therapy: an in vitro study.

OBJECTIVES: The purpose of this study was to evaluate the antimicrobial effect of toluidine blue O (TBO), in combination with either a helium/neon (HeNe) laser or a light-emitting diode (LED), on the viability and architecture of Streptococcus mutans biofilms. METHODS: Biofilms were grown on hydroxyapatite discs in a constant depth film fermentor fed with artificial saliva that was supplemented with 2% sucrose four times a day, thus producing a typical 'Stephan pH curve'. Photodynamic therapy was subsequently carried out on biofilms of various ages with light from either the HeNe laser or LED using energy densities of between 49 and 294 J/cm(2). RESULTS: Significant decreases in the viability of S. mutans biofilms were only observed when biofilms were exposed to both TBO and light, when reductions in viability of up to 99.99% were observed with both light sources. Overall, the results showed that the bactericidal effect was light dose-dependent and that older biofilms were less susceptible to photodynamic therapy. Confocal laser scanning microscopy images suggested that lethal photosensitization occurred predominantly in the outermost layers of the biofilms. CONCLUSIONS: Photodynamic therapy may be a useful approach in the treatment of dental plaque-related diseases.