Background and aim: Polychromatic light is actively used in medicine. However, its oncological safety and effect against cytotoxic therapy remains poorly studied. Multiple myeloma (MM) develops in the bone marrow and therefore malignant plasma cells are inaccessible to direct exposure to light. The aim of our work was to study the influence of polychromatic visible and infra-red light (pVIS + pIR) on growth and sensitivity of the myeloma cells to the cytotoxic effect of drug bortezomib (BTZ) through systemic mechanism.
Materials and methods: We explored the effect of volunteers blood sera after their 4-daily irradiations with pVIS + pIR light (480-3400 nm) on growth and viability of the human myeloma RPMI 8226 cells in the presence of BTZ at its application in 2 modes: short-term (1 h, 300 nM) and long-term (96 h, 5 nM). Viability and proliferative activity of cells was evaluated by MTT assay.
Results: It was found that photomodified blood sera delayed growth of myeloma RPMI 8226 cells (by 25 % in 48 h and 23 % in 96 h) but had no effect on spontaneous and mitogen-induced proliferation of autologous peripheral blood T- and B-lymphocytes. We also revealed that pVIS + pIR did not change RPMI 8226 cells sensitivity to BTZ.
Conclusion: The results suggest the systemic mechanism of polychromatic light and argue in favor of its oncological safety during/after BTZ therapy of MM patients without effect on the drug cytotoxicity.
Background: Photobiomodulation presents stimulatory effects on tissue metabolism, constituting a promising strategy to produce bone tissue healing.
Objective: the aim of the present study was to investigate the in vivo performance of PBM using an experimental model of cranial bone defect in rats.
Material and Methods: rats were distributed in 2 different groups (control group and PBM group). After the surgical procedure to induce cranial bone defects, PBM treatment initiated using a 808 nm laser (100 mW, 30 J/cm2, 3 times/week). After 2 and 6 weeks, animals were euthanized and the samples were retrieved for the histopathological, histomorphometric, picrosirius red staining and immunohistochemistry analysis.
Results: Histology analysis demonstrated that for PBM most of the bone defect was filled with newly formed bone (with a more mature aspect when compared to CG). Histomorphomeric analysis also demonstrated a higher amount of newly formed bone deposition in the irradiated animals, 2 weeks post-surgery. Furthermore, there was a more intense deposition of collagen for PBM, with ticker fibers. Results from Runx-2 immunohistochemistry demonstrated that a higher immunostaining for CG 2 week’s post-surgery and no other difference was observed for Rank-L immunostaining.
Conclusion: This current study concluded that the use of PBM was effective in stimulating newly formed bone and collagen fiber deposition in the sub-critical bone defect, being a promising strategy for bone tissue engineering.
The aim of this study was to test the application in vitro of different laser wavelengths at a low fluence in combination or not with proper photosensitizing dyes on Candida albicans biofilm with or without a synthetic killer decapeptide (KP).
Candida albicans SC5314 was grown on Sabouraud dextrose agar plates at 37°C for 24 h. Cells were suspended in RPMI 1640 buffered with MOPS and cultured directly on the flat bottom of 96-wells plates. The previously described killer decapeptide KP was used in this study.
Three different combinations of wavelengths and dyes were applied, laser irradiation has been performed at a fluence of 10 J/cm2. The effect on C. albicans biofilm was evaluated by the XTT assay. Microscopic observations were realized by fluorescence optic microscopy with calcofluor white and propidium iodide.
Compared with control, no inhibition of C. albicans biofilm viability was obtained with application of red, blue and green lasers alone or with any combination of red diode laser, toluidine blue and KP. The combined application of blue diode laser with curcumin and/or KP showed always a very significant inhibition, as curcumin alone and the combination of curcumin and KP did, while combination of blue diode laser and KP gave a less significant inhibition, the same obtained with KP alone. The combined application of green diode laser with erythrosine and/or KP showed always a very significant inhibition, as the combination of erythrosine and KP did, but no difference was observed with respect to the treatment with erythrosine alone. Again, combination of green diode laser and KP gave a significant inhibition, although paradoxically lower than the one obtained with KP alone.
Treatment with KP alone, while reducing biofilm viability did not cause C. albicans death in the adopted experimental conditions. On the contrary, combined treatment with blue laser, curcumin and KP, as well as green laser, erythrosine and KP led to death most C. albicans cells.
The combination of laser light at a fluence of 10 J/cm2 and the appropriate photosensitizing agent, together with the use of KP, proved to exert differential effects on C. albicans biofilm.
Background and Aims: Dental caries is a global concern and different materials and methods were proposed for its prevention.
The aim of this study was evaluation of the effect of different demineralizing agents with and without diode laser radiation on the microhardness of primary molars enamel.
Materials and Methods: 48 primary molar teeth were used in this study. The enamel blocks were prepared. Primary microhardness values were also measured. All samples were demineralized, then demineralization was approved by a DIAGNOdent pen. The remineralization was done into the buccal and lingual surfaces of the samples as follows:
Group 1: CPP-ACP, Group 2: CPP-ACPF, Group 3: MI varnish, Group 4: NaF varnish. The lingual surfaces received diode laser irradiation. Finally, a secondary microhardness test was performed on all samples. Statistical analyses were done and a P-value less than 0.05 was considered to be statistically significant.
Results: A comparison between the primary and the secondary microhardness values showed significant differences (P = 0.003). The highest secondary microhardness values belonged to the MI varnish +laser group.
Conclusion: Application of the agents, containing the combination of Ca, P, and F, was significantly better than others in increasing the microhardness of the enamel. Although the application of diode laser increased the hardness of the enamel.
Background and Aims: Dentin hypersensitivity is a frequent oral condition among patients suffering from gingival recession. Recent studies have suggested that photobiomodulation has the potential to reduce inflammation and relieve pain. The present study aims to assess the effectiveness of a new design of photobiomodulation toothbrush with specific irradiation parameters as a homecare device in treating dentin hypersensitivity and to compare its therapeutic effect with that of fluoride varnish.
Materials and Methods: Thirty patients with gingival recession and dentin hypersensitivity were selected and randomly assigned to three groups of equal size: fluoride varnish, photobiomodulation, and the combination. Dentin pain and hypersensitivity were measured using visual analog scale (VAS) by two distinct tests: the contact test with a periodontal probe and the air blast test on the areas of gingival recession and denuded root; once at baseline and again one month after the initial application of treatments. Laser irradiation was carried out at the wavelength of 660 nm in CW with an output power of 40 mW for 30 seconds per spot (1.2 J per spot, 6 J/cm2 energy density, and 200 mW/cm2 power density), perpendicularly to denuded root surfaces in non-contact mode.
Results: A significant reduction in dentin pain and hypersensitivity was observed in all three groups. However, the reduction was significantly greater in the combination group.
Conclusion: At-home treatment of dentin hypersensitivity with photobiomodulation toothbrush is a convenient, safe, and effective method for the management of dentin hypersensitivity.
Background and aims: Several studies highlighted how the ameloblasts, secretory cells responsible of the tooth enamel formation, are highly sensitive to changes in their environment. Due to enamel maturation, their dysfunctions during a limited period of tooth development may lead to permanent morphological consequences, namely Developmental Enamel Defects (DED). The aim of this study was to show the advantages of Er:YAG laser for DED treatment.
Subjects and methods: The case report presented describes the treatment, by Er:YAG laser, of some DED lesions present in the upper incisors of a young patient. The settings used were: 1W power, 100mJ energy, 10 Hz frequency corresponding to a Fluence of 0.318 J/cm2 per pulse or 3, 18 J/cm2.
Results: The patient, even in absence of local anesthesia, did not feel any pain or discomfort during and after intervention. Follow-up at 2, 6 and 12 months did not show any problems in an aesthetic point of view as well as regarding hypersensitivity.
Conclusions: The use of Er:YAG laser for the treatment of developmental enamel defects in frontal teeth is a safe, painless and minimally invasive; moreover, it is able to assure a good aesthetic result.