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Objective The aim of this study is to assess if low-level laser therapy (LLLT) alleviates pain after the placement of orthodontic alignment archwire and if there could be a specific indication for the usage of LLLT according to the amount of dental crowding. Materials and Methods Ninety subjects were included and randomly assigned to the tested group (orthodontic treatment and LLLT), placebo group (orthodontic treatment and simulated LLLT), and control group (orthodontic treatment only). Inclusion criteria are age between 13 and 30 years, completely erupted mandibular teeth, and lower crowding of ≥3 mm. Exclusion criteria are spaces or diastema in the lower arch, ectopic teeth, treatment plan including extractions or the use of auxiliary devices, and previous orthodontic treatment. Patients reported the pain experienced by using a numeric rating scale, ranging from 0 to 10, at specific time intervals, that is, 2 hours, 6 hours, 24 hours, and from day 2 to 7. Kruskal–Wallis H Test was used to assess differences in the maximum pain and pain experienced at each time interval among the three groups and in the maximum pain reported among subjects with different degree of crowding. Results The final sample consisted of 84 patients, 41 male and 43 female patients, with a mean age of 16.5 ± 2.8 years. The pain experienced at each time interval and the maximum pain score were significantly lower in the tested group, whereas no differences were found between control and placebo groups. Moreover, no differences were found in the pain experienced among subjects with mild, moderate, and severe incisor crowding in all groups. Conclusions LLLT is effective in alleviating the intensity and duration of pain experienced by patients after the engagement of alignment archwire. However, there is no specific indication for the usage of LLLT according to the amount of crowding.

Aim. In periodontology lasers have been suggested for the photodynamic therapy (PDT): such therapy can be defined as the inactivation of cells, microorganisms, or molecules induced by light and not by heat. The aim of this study was to evaluate results of PDT using a 980 nm diode laser (Wiser Doctor Smile, Lambda SPA, Italy) combined with hydrogen peroxide, comparing a pulsed diode laser (LI) activity to a high-frequency superpulsed diode laser (LII).Materials and Methods. Primary fibroblasts and keratinocytes cell lines, isolated from human dermis, were irradiated every 48 h for 10 days using LI and LII combined with SiOxyL+™Solution (hydrogen peroxide (HP) stabilized with a glycerol phosphate complex). Two days after the last irradiation, the treated cultures were analyzed by flow cytofluorometry (FACS) and western blotting to quantify keratin 5 and keratin 8 with monoclonal antibodies reactive to cytokeratin 5 and cytokeratin 8. Antimicrobial activity was also evaluated.Results. Both experimental models show the superiority of LII against LI. In parallel, stabilized HP provided better results in the regeneration test in respect to common HP, while the biocidal activity remains comparable.Conclusion. The use of high-frequency lasers combined with stabilized hydrogen peroxide can provide optimal results for a substantial decrease of bacterial count combined with a maximal biostimulation induction of soft tissues and osteogenesis.

Mesenchymal stem cells (MSCs) from bone marrow are a recent source for tissue engineering. Several studies have shown that low-level laser irradiation has numerous biostimulating effects. The purpose of this trial was to evaluate the effects of Nd:Yag laser irradiation on proliferation and differentiation of MSCs induced into the osteoblastic lineage. MSCs were collected from adult human bone marrow, isolated, and cultured in complete medium (α-MEM). Subsequently, they were treated with osteogenic medium, seeded in three-dimensional collagen scaffolds, and incubated. We used six scaffolds, equally divided into three groups: two of these were irradiated with Nd:Yag laser at different power levels (15 Hz, 100 mJ, 1.5 W, and one with a power level of 15 Hz, 150 mJ, 2.25 W), and one was left untreated (control group). Evaluations with specific staining were performed at 7 and 14 days. After 7 days, proliferation was significantly increased in scaffolds treated with laser, compared with the control scaffold. After 14 days, however, laser irradiation did not appear to have any further effect on cell proliferation. As concerns differentiation, an exponential increase was observed after 14 days of laser irradiation, with respect to the control group. However, this was a pilot study with very limited sample size, we conclude, that low-level laser irradiation might lead to a reduction in healing times and potentially reduces risks of failure. © 2012 Springer-Verlag London Ltd