Low-level laser therapy is effective in controlling postoperative pain in lower third molar extractions: a systematic review and meta-analysis.

This systematic review aimed to evaluate the effectiveness of low-level laser therapy in controlling postoperative pain in lower third molar extractions. A search was carried out in MEDLINE/PubMed, Web of Science and Cochrane Library (CENTRAL) databases, using the "low-level laser therapy", "photobiomodulation therapy", "impacted mandibular third molar", "mandibular third molar", "third molar extraction" descriptors and 2625 studies were found, including only randomized clinical trials published until July 2020, with no restrictions on language and country of study. Selected studies were submitted to initial screening based on the reading of titles, abstracts and full article, and duplicate studies were excluded. Overall, 2562 articles were found, of which only 15 randomized clinical trials were included in this review. A total of 648 patients (16-44 years) who received low-level laser therapy as an intervention and placebo in their control group were evaluated. The pain evaluation criterion was the Visual Analog Scale (VAS) on the second and seventh days after surgery. Photobiomodulation with low-level laser showed statistically significant reduction in postoperative pain in lower third molar extractions, both on the second (MD: - 0.59; CI: - 0.92, - 0.27) and seventh day after surgery (MD: - 0.76; CI: - 1.21, - 0.32).

Evaluation of dental enamel microproperties after bleaching with 35% hydrogen peroxide and different light sources: An in vitro study.

BACKGROUND: To evaluate the tooth enamel surface morphology after the action of 35% hydrogen peroxide with and without LED activation. MATERIAL AND METHODS: 70 bovine incisors with an enamel surface of 4x4x3 mm were used, prepared for reading superficial microhardness and roughness. Specimens were randomly distributed and divided into 7 experimental groups (n = 10); G1 = artificial saliva; G2 = 35% HP - 2 sessions (3x15´); G3 = Phosphoric Acid + 35% HP - 3 sessions (3x15´); G4 = 35% HP - 2 sessions (3x15´) + blue LED; G5 = 35% HP - 2 sessions (3x15´) + green LED; G6 = 35% HP - 2 sessions (3x20´) + violet LED; G7 = Violet LED - 2 sessions (3x20´). The results were analyzed by the Anova, Wilcoxon, Dunnett and Tukey tests (α = 0.05). RESULTS: The G4 group showed a greater change in microhardness. Regarding roughness, the biggest mean difference between groups occurred in G2, G5 and G7. Optical microscopy showed a smooth enamel surface in groups G2, G5 and G7. CONCLUSIONS: Changes in the enamel surface were observed in relation to microhardness, but without significant changes in roughness, where the LED (green and violet) resulted in a smooth surface. Key words:Tooth whitening, superficial morphology, light, photoradiatio.