In Vitro Photobiomodulation Effects of Blue and Red Diode Lasers on Proliferation and Differentiation of Periodontal Ligament Mesenchymal Stem Cells.

Introduction: This study aimed to assess the photobiomodulation effects of blue and red lasers on the proliferation and osteogenic differentiation of periodontal ligament mesenchymal stem cells (PDLMSCs). Methods: PDLMSCs were cultured and tested in 4 groups. The first two groups were exposed to 445 nm diode laser irradiation (200 mW, 6 and 12 J/cm2 ), and the third group was exposed to 660 nm diode laser irradiation (50 mW, 4 J/cm2 ). The fourth group was also considered as the control group without irradiation. Cell viability/proliferation was assessed by MTT assay. RUNX2, alkaline phosphatase (ALP), collagen type 1 (col1), and osteocalcin (OCN) were evaluated by RT-PCR, and Alizarin red was used to evaluate the colonization. The data were analyzed by means of one-way analysis of variance. Results: The results of our study showed that cell survival/proliferation in the second group was significantly lower than that in the control group on days 1 and 7 (P<0.05). RT-PCR showed a significant increase in osteogenic genes in all three laser groups compared to the control group (P<0.05). All groups showed a significant increase in calcium content compared to the control group (P<0.05). ALP activity also confirmed the osteoblastic differentiation of cells in laser groups. Conclusion: 445 nm and 660 nm lasers with the studied parameters showed positive effects on the proliferation and osteoblastic differentiation of PDLMSCs.

Evaluation of the effect of photodynamic therapy with Curcumin and Riboflavin on implant surface contaminated with Aggregatibacter actinomycetemcomitans.

BACKGROUND: Peri-implantitis is a destructive inflammatory disease affecting both hard and soft tissues of the osseointegrated implant and causing bone loss and envelope surrounding the implant. The study aimed at evaluating the effect of Photodynamic therapy with Curcumin and Riboflavin on the level of decontamination of implant surface impregnated with Aggregatibacter actinomycetemcomitans (A.a) biofilm. MATERIALS AND METHODS: In this experimental and laboratory study, 42 implants (4.3 mm in diameter and 8 mm in length) were infected with A.a. bacterial suspension. Then, the implants carrying A.a biofilm were randomly divided into seven groups (n = 6). The groups included: 1- a negative control group (without treatment), 2- a positive control group of Chlorhexidine 0.12 %, 3- a Curcumin (5 mg/ ml) group, 4- a Riboflavin (0.5 %) group, 5- an LED irradiation group (390-480 nm), 6- a photodynamic therapy with Curcumin group, and 7- a photodynamic therapy with Riboflavin group. Then, the implants were sonicated and the amount of CFU/mL of each sample was calculated. One-way ANOVA and Tamhane tests were used to analyze the data. RESULTS: The lowest mean number of colonies of A.a (CFU/ mL) were seen in the following groups, respectively: the positive control group of Chlorhexidine 0.12 %, the photodynamic therapy with Curcumin group, the photodynamic therapy with Riboflavin group, the Curcumin (5 mg/ ml) group, the Riboflavin (0.5 %) group, the LED radiation group, and the negative control group. The use of photodynamic therapy with Curcumin significantly reduced the number of colonies of A.a (CFU/ mL) in comparison with the photodynamic therapy with Riboflavin group (p = 0.004), the Riboflavin group (p = 0.045), the LED radiation group (p = 0.012), and the negative control group (p = 0.007). CONCLUSION: aPDT with Curcumin and LED can reduce A.a biofilm on implant surfaces and can be used as a safe and non-invasive disinfection method to reduce A.a biofilm on implant surfaces.

The influence of different mode of power density during antimicrobial photodynamic therapy for photokilling of Streptococcus mutans.

BACKGROUND: The aim of this study was to evaluate the inactivation potency of riboflavin and curcumin plus blue diode laser against Streptococcus mutans with different power densities. MATERIALS AND METHODS: In this in vitro study, standard-strain S. mutans was exposed to curcumin and riboflavin plus blue diode laser with different power densities (0.4-1.0 W/cm2) as well as chlorhexidine (CHX). The colony forming units (CFUs)/mL was calculated. Data were analyzed by one-way ANOVA. RESULTS: Antibacterial analysis indicated that the blue diode laser irradiation with curcumin and riboflavin provided a satisfactory reduction of the S. mutans level. In addition, S. mutans was more affected by curcumin + blue diode laser when the power density was set to 1.0 W/cm2 (P < 0.0001). Meanwhile, bacterial suspensions treated with CHX showed maximum colony number reduction, compared with the control (P < 0.0001). CONCLUSION: This study showed the blue diode laser along with curcumin had strong bactericidal effect on S. mutans, and this effect improved by increasing the power density.

In Vitro Effect of Photodynamic Therapy with Indocyanine Green Followed by 660 nm Photobiomodulation Therapy on Fibroblast Viability.

This in vitro study sought to assess the effect of repetitive PBMT on the viability of fibroblasts following aPDT with indocyanine green (ICG). In this in vitro experimental study, human gingival fibroblasts (HGFs) were obtained and incubated in a culture medium. After reaching 10 000 cells cm-2 , the cells were divided into five groups of control, aPDT with ICG and 808 nm (energy density of 24 J cm-2 ), PBMT immediately after aPDT, PBMT with 660 nm (energy density of 7.2 J cm-2 ) immediately and 24 h after aPDT and PBMT immediately and 24 and 48 h after aPDT in 48-well plates. Cell viability was evaluated using the methyl thiazolyl tetrazolium (MTT) assay after 1, 4 and 7 days of incubation. Statistical analyses were performed using one-way ANOVA. Cell viability significantly decreased in group 2 (P < 0.002). We observed no significant increase in cell viability at any time point in group 3 (P > 0.05). Cell viability significantly increased in groups 4 and 5 after the first day of incubation (P < 0.000). Emission of 660 nm as PBMT for two and three times along with passage of time would increase the viability of HGFs following aPDT with ICG.

Effect of Different Energy Densities of 915 nm Low Power Laser on the Biological Behavior of Human Gingival Fibroblast Cells In Vitro.

Photobiomodulation is recognized as an effective method for adjunct therapy in periodontal treatments. Our purpose in this study was to investigate the effects of different energy densities of 915 nm diode laser on the viability and viability capacity of human gingival fibroblast cells. Cell samples were examined in five groups, including four irradiation groups with low-level diode laser 915 nm, 1, 2, 3, 4 J cm-2 and a control group (no Laser irradiation). Cell viability and viability were measured 1, 3 and 5 days after irradiation by MTT and DAPI assay. Statistical differences between groups at any time were analyzed by one-way ANOVA and a post hoc Turkey's test. The cell viability and viability capacity increased on the third day at an energy density of 3 J cm-2 ; (P-value = 0.007) and the fifth day at energy densities of 2, 3 and 4 J cm-2 was recorded compared with the control group (P-value = 0.000). Also, a significant decrease in the viability and viability of irradiated cells with an energy density of 1 J cm-2 was found (P-value = 0.033). According to our results, Photobiomodulation with 915 nm diode laser has a positive stimulating effect on the viability and viability capacity of human gingival fibroblast cells.

Effects of Photobiomodulation Therapy with Various Laser Wavelengths on Proliferation of Human Periodontal Ligament Mesenchymal Stem Cells.

Several methods have been proposed to enhance the regeneration and healing time in periodontal therapy. Photobiomodulation therapy (PBMT) is a recently suggested novel technique for this purpose. This study aimed to compare the efficacy of PBMT with various laser wavelengths and energy densities on proliferation of human periodontal ligament mesenchymal stem cells (PDLMSCs). The wells containing PDLMSCs were subjected to laser irradiation at 635, 660, 808 and 980 nm wavelengths with 1, 1.5, 2.5 and 4 J cm-2 energy densities. Cell proliferation and viability were evaluated after 1, 3 and 5 days with the methyl thiazolyl tetrazolium (MTT) assay and 4,6-diamidino-2-phenylindole (DAPI) staining. No significant difference was observed among the experimental and the control groups on day 1 (P > 0.05). On day 3, 808 nm laser at 4 J cm-2 energy density and 980 nm laser at all densities had significant differences with control group. On day 5, the control group had significant differences in cell proliferation with 808 nm laser at 2.5 and 4 J cm-2 energy densities, and 980 nm laser at all densities. PBMT with 635, 660, 808 and 980 nm wavelengths increased the proliferation of PDLMSCs but the maximum cell viability was prominent after irradiation by 980 nm laser with energy density of 4 J cm-2 on day 3.

Blue Light Photodynamic Therapy With Curcumin and Riboflavin in the Management of Periodontitis: A Systematic Review.

Introduction: The aim of this article was to evaluate reports in the scientific literature that used antimicrobial photodynamic therapy (aPDT) with a blue light source and curcumin and riboflavin as photosensitizers in the management of periodontitis. Methods: The search was conducted in electronic databases, including PubMed, Web of Science, and Scopus, with the keywords "photodynamic therapy", "antimicrobial photodynamic therapy", "laser activated disinfection", "photoactivated disinfection", "light activated disinfection" "LED", "Periodontitis", "Curcumin", "Riboflavin", and "periodontitis" from 2012 to 2020. Results: After evaluating a total of 24 relevant articles, 13 articles were selected, full texts were read, and the data were extracted and placed in a table. Conclusion: Reviewing articles showed that curcumin as a photosensitizer activated by a blue wavelength is effective in the elimination of the various bacterial species involved in periodontal disease, and to the best of our knowledge, there is no study that has shown this substance does not reduce bacteria. According to the result of the articles, riboflavin as a photosensitizer activated by blue light can reduce bacteria that are involved in periodontitis, but other studies have reported that blue light alone can also reduce bacteria significantly. Therefore, more in-vitro and clinical trial studies are needed to give a more conclusive opinion on the effectiveness of riboflavin as a photosensitizer in the treatment of periodontitis.

Photobiomodulation Effect of Different Diode Wavelengths on the Proliferation of Human Gingival Fibroblast Cells.

This study is focused on comparing the effect of various energy densities and wavelengths of diode lasers on the proliferation of human gingival fibroblast (HGF) cells in vitro. In this study, 204 sample cells were examined in 4 test groups (laser radiation) and 1 control group (non-laser radiation). The proliferation rate of radiated cells with wavelengths of 635, 660, 808 and 980 nm and the densities of 1, 1.5, 2.5 and 4 J cm-2 was measured after 1, 3 and 5 days using the MTT assay. The proliferation rate of human gingival fibroblast (HGF) cells in test groups was increased on day 1 at wavelengths of 635, 808 and 980 nm and on day 3 at the wavelength of 980 nm compared with the control group. Our findings denoted that the photobiomodulation therapy increased the proliferation rate of HGF. The most desirable laser radiation setting, which led to the highest proliferation rate of the cells, included 980 nm wavelength with 1, 1.5 and 4 J cm-2 energy densities and 635 nm wavelength with 4 J cm-2 energy density.

Assessment of the Photobiomodulation Effect of a Blue Diode Laser on the Proliferation and Migration of Cultured Human Gingival Fibroblast Cells: A Preliminary In Vitro Study.

Introduction: Photobiomodulation therapy (PBM) is emerging as an effective strategy for the management of wound healing. The application of red and near infra-red light sources in laser therapy has been the subject of most researches in recent literature. Considering the lack of sufficient evidence in assessing the blue light in PBM, we aimed to investigate the photobiomodulation effect of a blue diode laser on the proliferation and migration of cultured human gingival fibroblast cells as a preliminary in vitro study. Methods: Human gingival fibroblast cells were irradiated with a blue diode laser at a 445 nm wavelength. Irradiation was done using three different powers of 200 mW (irradiation times of 5, 10,15, and 20 seconds); 300 mW (irradiation times of 5, 10, and 15 seconds); and 400 mW (irradiation times of 5 and 10 seconds). The fibroblast cells without laser exposure were considered as control. After 24 hours of incubation, the MTT assay and the wound scratch test were performed on the cells to investigate the biomodulation effect of the blue laser on the proliferation and migration of the cells respectively. The results were analyzed by one-way ANOVA and a post-hoc Tukey test with a P value <0.05 as a statistical significance level. Results: PBM with blue diode laser at power densities of 400 mW/cm2 with irradiation times of 10 and 15 seconds corresponding to energy densities of 4 and 6 J/cm2 exerted the statistically significant positive effect on both proliferation and migration of gingival fibroblast cells. Conclusion: Considering the encouraging findings of this study, PBM with blue diode laser can promote proliferation and migration of human gingival fibroblasts, the key cells involved in the process of oral wound healing.