Laser acupuncture to reduce temporomandibular disorder (TMD) symptoms: systematic review and meta-analysis.

The application of low-level laser therapy (LLLT) to acupuncture points may produce effects similar to that of needle stimulation in patients with temporomandibular disorders (TMD). This systematic review was conducted according to the Cochrane Collaboration guidelines and aimed to address clinical questions using the following strategy: Patient/Problem, Intervention, Comparison, and Outcome (PICO). A comprehensive literature search was performed upto April 26, 2023, across nine electronic databases (BVS, PubMed, Scopus, Embase, Web of Science, ScienceDirect, Cochrane Library, Latin American and Caribbean Health Sciences Literature (LILACS), and Google Scholar) supplemented with gray literature. The risk of bias in randomized and nonrandomized clinical trials was assessed using two tools: risk-of-bias (RoB) 2 and Risk Of Bias In Non-randomised Studies-of Interventions (ROBINS-I). Meta-analysis involved the extraction of mean and standard deviation values for spontaneous pain and mouth opening levels. Seven studies were included in this review, all of which used LLLT. The applied wavelengths ranged from 690 to 810 nm without significant variations in light emission patterns. LLLT demonstrated a significant reduction in instantaneous pain levels (standard mean difference [SMD] = 3.85; 95% confidence interval [CI] = 2.09, 5.62; p < 0.003) and an improvement in instantaneous mouth opening ability (mean difference [SMD] = -7.15; 95% CI = -11.73, -2.58; p < 0.002), with low certainty of evidence. LLLT may alleviate symptoms in patients with TMD; however, caution should be exercised when interpreting the results because of protocol variations among studies and the limited number of studies included in the meta-analysis.

Low-level laser therapy (LLLT) improves alveolar bone healing in rats.

The main objective of the present study was to evaluate the effect of low-level laser therapy (LLLT) in enhancing bone healing in irradiated alveolus post-tooth extraction. Sixty male Wistar rats (180 ± 10 g) were used in the present study. The left maxillary first molars were extracted, and the alveolar region was irradiated by diode laser device (GaAlAs) immediately after extraction and for more 3-day daily applications. The animals were randomly assigned into two groups: control group (n = 30, with left maxillary molar extraction-CG) and experimental group (n = 30, with tooth extraction and low-level laser therapy applied to the dental alveolus for 42 s-EG). These groups were divided into subgroups (five rats per subgroup) according to the observation time point-1, 2, 3, 5, 7, and 10 days-post-tooth extraction. The maxillary bone was separated, and the specimens were stained with hematoxylin and eosin, Masson's trichrome, and picrosirius red and immunohistochemistry for RUNX-2. Parametric and nonparametric tests were used with a significance level of 5%. LLLT accelerated bone healing with mature collagen fiber bundles and early new bone formation. Histomorphometric analysis revealed an increase of osteoblast (RUNX-2) and osteoclast (TRAP) activity and in the area percentage of cancellous bone in the lased alveolus compared to the control group. This increase was statistically significant (p < 0.05). Application of LLLT with a GaAlAs diode laser device enhanced bone healing and mineralization on alveolar region.

Evaluation of the chelating effect of chitosan solubilized in different acids.

AIM: This study aimed to compare, through dentin microhardness and colorimetric analysis, the chelating effect of 0.2% chitosan solubilized in different acids. MATERIALS AND METHODS: The second and third cuts of the cervical region of maxillary central incisors were divided into four quadrants, resulting in eight specimens, which were treated with 50 µL of solution for 5 min according to their group (n = 10): GI - 0.2% chitosan solubilized in 1% acetic acid; GII - 0.2% chitosan solubilized in 3.3% citric acid; GIII - 0.2% chitosan solubilized in 0.00145% hydrochloric acid; and GIV - 0.2% chitosan solubilized in 0.00112% nitric acid. A control was made from the chelating properties of the following acids: GV - 3.3% citric acid, GVI - 0.00145% hydrochloric acid, GVII - 0.00112% nitric acid, and GVIII - control (distilled water). Afterward, they were subjected to the Knoop microhardness tester with a load of 10 g for 15 s, resulting in three indentations of the root canal toward the cement. The measurements obtained were subjected to the one-way ANOVA test followed by Tukey's test (α =0.05). Subsequently dispensing the chitosan solutions, the same were subjected to colorimetric analysis. RESULTS: Chitosan solubilized in acetic acid, followed by chitosan in citric acid, provided a greater reducing effect compared to the other groups. Similar results were observed in the colorimetric analysis. CONCLUSION: It was concluded that the chelating ability of the chitosan solution solubilized in acetic acid is higher than solubilization in citric, hydrochloric, and nitric acids.