BACKGROUND AND OBJECTIVE

Orthodontic brackets predispose dental biofilm accumulation causing caries and gingivitis. Chlorhexidine is an adjunct to mechanical plaque removal, but has side-effects (tooth staining, bacterial resistance) due to long term use. This study tested the efficacy of Photodynamic Therapy, which produces reactive oxygen species, to reduce Streptococcus mutans in dental biofilm on orthodontic brackets.

A 5-day S. mutans biofilm was grown on forty enamel-bracket specimens. Thirty-nine specimens were randomized to three treatment groups: A. Distilled Water; B. 0.12% Chlorhexidine (CHX); C. Photodynamic Therapy (PDT) using Toluidine Blue O (TBO) as a photosensitizer, activated by red LED (630nm). After treatment, one random specimen from each group was viewed under Environmental Scanning Electron Microscopy (ESEM); the other 12 specimens, biofilms were collected, weighed, and cultured onto BHI agar plates to determine the number of CFU/mg. For baseline evaluation, one clean and one untreated specimens were preserved for ESEM.

Based on Tukey HSD test, group A had the most S. mutans (37.0573 CFU/mg) and was significantly different (p < 0.05) from groups B (0.1712 CFU/mg) and C (1.1193 CFU/mg), where both showed less bacteria than group A. The statistical difference between groups B and C was insignificant. ESEM images showed specimen A covered with more abundant and denser S. mutans biofilm than specimens B and C, with almost similar morphology showing sparse, less dense, and disintegrated biofilm with unclear cellular walls and presence of amorphous masses.

Both Photodynamic Therapy and 0.12% Chlorhexidine showed a significant reduction of S. mutans in dental biofilm on orthodontic brackets. However, there is no significant difference between them in reducing S. mutans CFU/mg. Photodynamic therapy could be an alternative adjunctive tool to mechanical removal of plaque adhered to orthodontic brackets.

BACKGROUND AND OBJECTIVE

Orthodontic brackets predispose dental biofilm accumulation causing caries and gingivitis. Chlorhexidine is an adjunct to mechanical plaque removal, but has side-effects (tooth staining, bacterial resistance) due to long term use. This study tested the efficacy of Photodynamic Therapy, which produces reactive oxygen species, to reduce Streptococcus mutans in dental biofilm on orthodontic brackets.

A 5-day S. mutans biofilm was grown on forty enamel-bracket specimens. Thirty-nine specimens were randomized to three treatment groups: A. Distilled Water; B. 0.12% Chlorhexidine (CHX); C. Photodynamic Therapy (PDT) using Toluidine Blue O (TBO) as a photosensitizer, activated by red LED (630nm). After treatment, one random specimen from each group was viewed under Environmental Scanning Electron Microscopy (ESEM); the other 12 specimens, biofilms were collected, weighed, and cultured onto BHI agar plates to determine the number of CFU/mg. For baseline evaluation, one clean and one untreated specimens were preserved for ESEM.

Based on Tukey HSD test, group A had the most S. mutans (37.0573 CFU/mg) and was significantly different (pCONCLUSION

Both Photodynamic Therapy and 0.12% Chlorhexidine showed a significant reduction of S. mutans in dental biofilm on orthodontic brackets. However, there is no significant difference between them in reducing S. mutans CFU/mg. Photodynamic therapy could be an alternative adjunctive tool to mechanical removal of plaque adhered to orthodontic brackets.

Indocyanine Green/therapeutic use* ; Photochemotherapy ; Combined Modality Therapy ; Anti-Infective Agents

Objective: To investigate the effects of low-dose photodynamic therapy on the proliferation, regulation, and secretion functions of human adipose mesenchymal stem cells (ADSCs) and the related mechanism, so as to explore a new method for the repair of chronic wounds. Methods: The experimental research methods were adopted. From February to April 2021, 10 patients (5 males and 5 females, aged 23 to 47 years) who underwent cutaneous surgery in the Department of Dermatology of the First Affiliated Hospital of Army Medical University (the Third Military Medical University) donated postoperative waste adipose tissue. The cells were extracted from the adipose tissue and the phenotype was identified. Three batches of ADSCs were taken, with each batch of cells being divided into normal control group with conventional culture only, photosensitizer alone group with conventional culture after being treated with Hemoporfin, irradiation alone group with conventional culture after being treated with red light irradiation, and photosensitizer+irradiation group with conventional culture after being treated with Hemoporfin and red light irradiation, with sample number of 3 in each group. At culture hour of 24 after the treatment of the first and second batches of cells, the ADSC proliferation level was evaluated by 5-ethynyl-2'-deoxyuridine staining method and the migration percentage of HaCaT cells cocultured with ADSCs was detected by Transwell experiment, respectively. On culture day of 7 after the treatment of the third batch of cells, the extracellular matrix protein expression of ADSCs was detected by immunofluorescence method. The ADSCs were divided into 0 min post-photodynamic therapy group, 15 min post-photodynamic therapy group, 30 min post-photodynamic therapy group, and 60 min post-photodynamic therapy group, with 3 wells in each group. Western blotting was used to detect the protein expressions and calculate the phosphorylated mammalian target of rapamycin complex (p-mTOR)/mammalian target of rapamycin (mTOR), phosphorylated p70 ribosomal protein S6 kinase (p-p70 S6K)/p70 ribosomal protein S6 kinase (p70 S6K) ratio at the corresponding time points after photodynamic therapy. Two batches of ADSCs were taken, and each batch was divided into normal control group, photodynamic therapy alone group, and photodynamic therapy+rapamycin group, with 3 wells in each group. At culture minute of 15 after the treatment, p-mTOR/mTOR and p-p70 S6K/p70 S6K ratios of cells from the first batch were calculated and detected as before. On culture day of 7 after the treatment, extracellular matrix protein expression of cells from the second batch was detected as before. Data were statistically analyzed with one-way analysis of variance and least significant difference test. Results: After 12 d of culture, the cells were verified as ADSCs. At culture hour of 24 after the treatment, the ADSC proliferation level ((4.0±1.0)% and (4.1±0.4)%, respectively) and HaCaT cell migration percentages (1.17±0.14 and 1.13±0.12, respectively) in photosensitizer alone group and irradiation alone group were similar to those of normal control group ((3.7±0.6)% and 1.00±0.16, respectively, P>0.05), and were significantly lower than those of photosensitizer+irradiation group ((34.2±7.0)% and 2.55±0.13, respectively, P<0.01). On culture day of 7 after the treatment, compared with those in normal control group, the expression of collagen Ⅲ in ADSCs of photosensitizer alone group was significantly increased (P<0.05), and the expressions of collagen Ⅰ and collagen Ⅲ in ADSCs of irradiation alone group were significantly increased (P<0.01). Compared with those in photosensitizer alone group and irradiation alone group, the expressions of collagen Ⅰ, collagen Ⅲ, and fibronectin of ADSCs in photosensitizer+irradiation group were significantly increased (P<0.01). Compared with those in 0 min post-photodynamic therapy group, the ratios of p-mTOR/mTOR and p-p70 S6K/p70 S6K of ADSCs in 15 min post-photodynamic therapy group were significantly increased (P<0.01), the ratios of p-p70 S6K/p70 S6K of ADSCs in 30 min post-photodynamic therapy group and 60 min post-photodynamic therapy group were both significantly increased (P<0.01). At culture minute of 15 after the treatment, compared with those in normal control group, the ratios of p-mTOR/mTOR and p-p70 S6K/p70 S6K of ADSCs in photodynamic therapy alone group were significantly increased (P<0.05 or P<0.01). Compared with those in photodynamic therapy alone group, the ratios of p-mTOR/mTOR and p-p70 S6K/p70 S6K of ADSCs in photodynamic therapy+rapamycin group were significantly decreased (P<0.05). On culture day of 7 after the treatment, compared with those in normal control group, the expressions of collagen Ⅰ, collagen Ⅲ, and fibronectin of ADSCs in photodynamic therapy alone group were significantly increased (P<0.01). Compared with those in photodynamic therapy alone group, the expressions of collagen Ⅰ, collagen Ⅲ, and fibronectin of ADSCs in photodynamic therapy+rapamycin group were significantly decreased (P<0.01). Conclusions: Low-dose photodynamic therapy can promote the proliferation of ADSCs, improve the ability of ADSCs to regulate the migration of HaCaT cells, and enhance the secretion of extracellular matrix protein by rapidly activating mTOR signaling pathway.
Adipose Tissue ; Female ; Fibronectins ; Humans ; Male ; Mesenchymal Stem Cells ; Photochemotherapy ; Photosensitizing Agents/pharmacology* ; Sirolimus/pharmacology* ; TOR Serine-Threonine Kinases

Photodynamic therapy (PDT) has developed rapidly in basic and clinical research, and its therapeutic prospects have received increasing attention. PDT has the advantages of minimally invasive, low toxicity, high selectivity, good reproducibility, protection of appearance and vital organ function, and has become a treatment. With the development of medicine, the field of application of PDT becomes more wildly, and brings a new direction for the treatment of oral diseases. This article reviews the basic principles, treatment elements and research results of PDT in the treatment of oral diseases.
Humans ; Mouth Diseases/drug therapy* ; Photochemotherapy ; Photosensitizing Agents/therapeutic use* ; Reproducibility of Results

ABSTRACT Lactobacillus acidophilus (L. acidophilus) is one of the etiological agents for dental caries and dominant in the deep carious lesion. L. acidophilus has also been identified in persistent root canal infection and also related to the failure of endodontic treatment. Photodynamic therapy is a therapeutic process involving the combination of a nontoxic photosensitizer and a light source. The excited photosensitizer reacts with reactive oxygen species (ROS), which induce injury and death of the microorganism. This study aimed to prove the effect of irradiation time of photodynamic therapy to the number of L. acidophilus. Forty-two Eppendorf tubes were treated with 0.5 ml L. acidophilus distributed into seven groups. Group 1 as the control group received no treatment. Groups 2, 3, 4, 5, 6 and 7 were treated with a combination of 0.5 ml toluidine blue O (TBO) as a photosensitizer and 630 nm photoactivated (Fotosan®) exposure time for 10, 20, 30, 40, 50 and 60 sec. Then, all were stored in an incubator of 37ºC for 48 h. Later, the colony-forming unit (CFU) was counted for each group. There were significant differences in the number of L. acidophilus in CFU of the various irradiation times. The longer the photodynamic therapy irradiation was, the lesser the number of live L. acidophilus became. At 50 sec and 60 sec irradiation, none of the L. acidophilus was found alive.
Photochemotherapy ; Lactobacillus acidophilus

To investigate the effect of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) on () biofilm. biofilms were constructed on a cell slide and treated with ALA-PDT.According to different light doses,the biofilms were divided into six groups:ALA-PDT group [ALA-PDT1 (50 J/cm),ALA-PDT2 group (100 J/cm),ALA-PDT3 group (200 J/cm)],ALA-only group (ALA group),light-only group (LED),and a negative control group (ALA-PDT-group).The biofilm structure and the ratio of the dead bacteria/live bacteria were observed using a laser confocal microscope (CLSM).Biofilm viability was measured using the XTT assay. CLSM showed that the biofilm structures of ALA group and LED group were not significantly different from that of ALA-PDT-group,whereas the biofilm structure was more seriously damaged in ALA-PDT1 group,ALA-PDT2 group,and ALA-PDT3 group than in the ALA-PDT-group.The ratios of the dead/live bacteria in ALA-PDT-group,ALA group,LED group,ALA-PDT1 group,ALA-PDT2 group,and ALA-PDT3 group were 0.350±0.033, 0.305±0.046, 0.330±0.032, 1.525±0.439, 2.293±0.148 and 3.092±0.189,respectively.ALA group(=0.003, =1.000)and LED group(=-0.025, =1.000)did not significantly differ from the ALA-PDT-group.However,the ratio of dead/live bacteria in ALA-PDT-group was significantly lower than those in ALA-PDT1 group (=-0.162, <0.001),ALA-PDT2 group (=-0.254, <0.001),and ALA-PDT3 group (=-0.352, <0.001).The values of the XTT assay were were 0.462±0.028,0.465±0.044,0.437±0.047,0.301±0.040,0.207±0.001,and 0.110±0.007,respectively,in ALA-PDT-group,ALA group,LED group,ALA-PDT1 group,ALA-PDT2 group,and ALA-PDT3 group.Although the values of XTT assay in ALA(=-0.044, =1.000)and LED groups (=-0.020, =1.000)did not significantly differ from that in ALA-PDT-group,it was significantly higher in ALA-PDT-group than in ALA-PDT1 group (=1.175, <0.001),ALA-PDT2 group (=1.942, <0.001),and ALA-PDT3 group (=-0.352, =2.742, <0.001). ALA-PDT has an inhibitory effect on biofilm.ALA-PDT destroys biofilm structure and inhibits biofilm viability.
Aminolevulinic Acid ; Biofilms ; Photochemotherapy ; Photosensitizing Agents ; Propionibacterium acnes

OBJECTIVE: To compare the anti-caries effect and safety of Er:YAG laser combined with fluoride and methylene blue-photodynamic therapy (MB-PDT). METHODS: A total of 28 rat dental caries models were established and randomly divided into seven groups: photodynamic therapy (PDT) group, laser combined with fluoride group, laser group, sodium fluoride group, and 0.9% saline control group. Spectrophotometric optical density was used to reflect the growth of Streptococcus mutans. Laser-induced fluorescence diagnostic (LF) instrument was utilized to detect the demineralization degree of dental caries. Histopathological sections were employed to observe the damage of dental pulp and buccal mucosa. RESULTS: The optical density (OD) value of the PDT and combination groups was significantly lower than that of other treatment groups (P<0.05). An increase in LF value and demineralization occurred in varying degrees with different treatment methods. Histopathological observation showed that pulp and buccal mucosa injury was more obvious in the combination group of 70 mw·cm⁻² and Er:YAG laser group compared with other groups. CONCLUSIONS Under the same parameters, the combined group and PDT have good germicidal efficacy, but PDT has fewer adverse reactions and less damage. It is an effective and safe method for caries prevention.
Cariostatic Agents ; Dental Caries/prevention & control* ; Fluorides ; Humans ; Laser Therapy ; Lasers, Solid-State ; Methylene Blue ; Photochemotherapy

PURPOSE: To evaluate the efficacy of focal verteporfin photodynamic therapy (PDT) in patients diagnosed with chronic central serous chorioretinopathy (CSC).METHODS: This study enrolled 52 eyes of 52 patients with chronic CSC who had received verteporfin PDT. The laser spot size of 26 eyes covering only the localized hyperfluorescent area in indocyanine green angiography was classified as focal PDT. The PDT spot size of the other 26 eyes covered the total area of retinal pigment epithelial detachment including the leaking point and was defined as conventional PDT. The central subfield thickness and subfoveal choroidal thickness were measured using Heidelberg Spectralis optical coherence tomography before PDT and at months 1, 3, 6, and 12 after PDT.RESULTS: The mean spot size of the PDT was 1,995 µm in the focal group and 2,995 µm in the conventional group. Central subfield thickness steadily decreased in both groups. The mean baseline subfoveal choroidal thickness for the two groups was 334.95 and 348.35 µm, respectively, with no significant difference (p = 0.602). Subfoveal choroidal thickness decreased significantly to 304.20 µm at 1 month, 284.85 µm at 3 months, 271.60 µm at 6 months, and 265.95 µm at 12 months in the focal group (p < 0.001, p < 0.001, p < 0.001, and p < 0.001, respectively, compared with baseline). In the conventional group, subfoveal choroidal thickness decreased significantly to 318.75, 300, 284, and 272 µm at 1, 3, 6, and 12 months, respectively (p < 0.001, p < 0.001, p < 0.001 and p < 0.001 compared with baseline). There were no significant differences between the two groups in subfoveal choroidal thickness based on PDT spot size at 1, 3, 6, and 12 months (p = 0.633, p = 0.625, p = 0.676, and p =0.755, respectively).CONCLUSIONS: Focal verteporfin PDT for CSC significantly decreased the subretinal fluid and sufoveal choroidal thickness to the same extent as conventional PDT.
Angiography ; Central Serous Chorioretinopathy ; Choroid ; Humans ; Indocyanine Green ; Photochemotherapy ; Retinal Detachment ; Subretinal Fluid ; Tomography, Optical Coherence

OBJECTIVE: This study aimed to evaluate the potential effects of cisplatin on photodynamic therapy (PDT) in breast cancer using a breast tumor-bearing mouse model. METHODS: In this study, breast tumor (experimental mammary tumour-6 cell)-bearing nude mice were used as experimental animals. Photolon® (photosensitizer, 2.5 mg/kg body weight [BW]) was injected intraperitoneally; after 2 hours, the tumors were irradiated (660 nm, 80 J/cm2) using a diode laser tool. Cisplatin (3 mg/kg BW) was injected intraperitoneally 1 hour before the Photolon® injection. RESULTS: Tumor volume increased over time in the control group and was not different from that in the cisplatin group. In the PDT group, the tumor volume increased on day 3, but not on day 7. In the cisplatin+PDT group, tumor volume increased on day 3 but decreased on day 7. There was no significant difference in the levels of thiobarbituric acid reactive substance (TBARS) in tumor tissues between the control and cisplatin groups. The levels of TBARS in the cisplatin+PDT group were higher (47%) than those in the PDT group. Analysis of tumor tissue transcriptomes showed that the expression of genes related to the inflammatory response including CL and XCL genes increased, while that of Fn1 decreased in the cisplatin+PDT group compared with the PDT group. CONCLUSION: These results suggest that cisplatin enhances the therapeutic effect of PDT in a breast tumor-bearing mouse model. However, further clinical studies involving patients with breast cancer is needed.
Animals ; Body Weight ; Breast Neoplasms ; Breast ; Cisplatin ; Humans ; Lasers, Semiconductor ; Mice ; Mice, Nude ; Photochemotherapy ; Thiobarbituric Acid Reactive Substances ; Transcriptome ; Tumor Burden