Preclinical study of a cost-effective photodynamic therapy protocol for treating oral candidoses

Antimicrobial photodynamic therapy with erythrosine and blue light on dental biofilm bacteria: study protocol for randomised clinical trial

INTRODUCTION

The objective is to investigate the effect of antimicrobial photodynamic therapy (aPDT) mediated by erythrosine and a blue light-emitting diode (LED) in the reduction of bacteria in dental biofilm.

METHODS AND ANALYSIS

This clinical trial will be conducted with 30 patients who have biofilm, but without the presence of periodontal pockets, and who are being treated at the Dental Clinic of Universidade Metropolitana de Santos. A split-mouth model will be used (n=30), with group 1 control (conventional treatment) and group 2 (conventional treatment and aPDT). The bicarbonate jet will be used to remove dental biofilm in both groups. The treatment will be carried out in one session. aPDT will be performed before cleaning/prophylaxis, only in group 2. Participants will rinse with the photosensitiser erythrosine (diluted to 1 mM) for 1 min of pre-irradiation time, so that the drug can stain all the bacterial biofilm. Then, the D-2000 LED (DMC) will be applied, emitting at a wavelength of ʎ=470 nm, radiant power of 1000 mW, irradiance of 0.532 W/cm2 and radiant exposure of 63.8 J/cm2. Irradiation will be performed until the biofilm of the cervical region is illuminated for 2 min/point (4 cm2). The microbiological examination will be performed from samples of supragingival biofilm collected from the gingival sulcus. Collection will be performed in each experimental site before irradiation, immediately after the irradiation procedure and after the prophylaxis. Colony-forming units will be counted and the data will be submitted for statistical analysis for comparison of pretreatment and post-treatment results and between groups (conventional X aPDT).

ETHICS AND DISSEMINATION

This study has been approved by the Ethics Committee of Universidade Metropolitana de Santos under process number 66984123.0.0000.5509. Results will be published in peer-reviewed journals and will be presented at conferences.

TRIAL REGISTRATION NUMBER

NCT05805761.

Photosensitizers Mediated Photodynamic Inactivation against Fungi

Superficial and systemic fungal infections are essential problems for the modern health care system. One of the challenges is the growing resistance of fungi to classic antifungals and the constantly increasing cost of therapy. These factors force the scientific world to intensify the search for alternative and more effective methods of treatment. This paper presents an overview of new fungal inactivation methods using Photodynamic Antimicrobial Chemotherapy (PACT). The results of research on compounds from the groups of phenothiazines, xanthanes, porphyrins, chlorins, porphyrazines, and phthalocyanines are presented. An intensive search for a photosensitizer with excellent properties is currently underway. The formulation based on the existing ones is also developed by combining them with nanoparticles and common antifungal therapy. Numerous studies indicate that fungi do not form any specific defense mechanism against PACT, which deems it a promising therapeutic alternative.

Efficacy of Rose Bengal and Curcumin mediated photodynamic therapy for the treatment of denture stomatitis in patients with habitual cigarette smoking: A randomized controlled clinical trial

BACKGROUND

Cigarette smoking in conjugation with bad oral hygiene is considered a typical predisposing factor for many oral diseases including denture stomatitis. This study investigated the effect of Rose Bengal (RB)-and Curcumin (CUR)-mediated photodynamic therapy (PDT) in comparison with nystatin therapy in the intervention of denture stomatitis in cigarette smokers.

METHODS

Overall, 45 habitual cigarette smokers aged ~58 years having denture stomatitis were categorized into three groups: Group-I - RB-mediated PDT, Group-II - CUR-mediated PDT, and Group-III - Nystatin therapy. The primary outcome of the interest was: counts of Candida colony from denture surface and palatal mucosa, calculated as CFU/mL, whereas the prevalence of Candida species determined in 3 research groups comprised the secondary outcome. Oral swab specimens were gathered from the denture surfaces and palatal mucosa. All clinical assessments were performed at baseline, 6 weeks, and 12 weeks.

RESULTS

C. albicans was the most prevalent yeast identified on both denture surfaces and palatal mucosa, followed by C. tropicalis and C. glabrata. A considerable decrease in the CFU/mL scores were observed in Group-I and Group-II at the end of the interventions and on the 12-week follow-up (p<0.05). Group-I, II, and III demonstrated clinical efficacy rates of 53%, 51%, and 49%, respectively.

CONCLUSION

CUR-and RB-mediated PDT was found to be as effective as topical Nystatin therapy for the intervention of denture stomatitis among cigarette smokers.

Erythrosine as a photosensitizer for antimicrobial photodynamic therapy with blue light-emitting diodes - An in vitro study

BACKGROUND

This study aims to test the absorbance of a new composition of erythrosine, its pH, cell viability and potential as a photo sensitizer against Candida albicans when irratiaded with blue light emitting-diode (LED).

METHODS

For pH and absorbance tests, erythrosine was prepared at a concentration of 0.03/ml. The cells of the L929 strain were cultured and the alamarBlue® assay was performed on samples to assess cell viability. For the microbiological essay, the strain of Candida albicans ATCC 90028 was selected. Yeast suspensions were divided into the following groups: control without irradiation or photosensitizer (C), irradiated group without photosensitizer (L), photosensitizer group without irradiation (0), and groups that received photosensitizer and irradiation, called aPDT groups.

RESULTS

Erythrosine had no significant changes in pH and its absorbance was also consistent (≅400 nm). When it came to cell viability, on the first day, the group that was in contact with the dye and irradiated with the LED in minimun power was found to have the higher cell proliferation. On day 3, both irradiated groups (maximum and minimum) showed the highest cell proliferation. In the microbiological essay with C. albicans, aPDT groups started to show microbial reduction after 60 and 90 s of irradiation and when irradiated for 120 s, 6 microbial reduction logs were found.

CONCLUSIONS

The erythrosine in question is a PS, with pH stability, blue light absorbance, cell viability and efficacy against C. albicans. More studies with this PS should be encouraged in order to verify its performance in aPDT.

Phytotherapy in the management of denture stomatitis: A systematic review and meta-analysis of randomized controlled trials

Medicinal plant extracts are commonly applied for infectious diseases and are perceived as alternatives to conventional antimicrobial agents. We aimed to confirm the efficacy of phytotherapy for denture stomatitis compared with conventional therapies and placebo. A comprehensive literature search was conducted in Pubmed, Embase, Cochrane Library (CENTRAL), Scopus, and Web of Science, in addition to manual searching. Randomized controlled trials (RCTs) published in English, and studying the treatment of denture stomatitis with herbal medicines, were included. The outcome measures included the relief of clinical signs, reduced Candida colony counts, adverse effects, and patient satisfaction. Nineteen RCTs were included for a systematic review based on selection criteria. Two of them were analyzed using a random-effects model. There was no difference in the relief of clinical signs (odds ratio (OR) = 0.96; 95% confidence interval (CI): 0.43-2.15) and microbiological improvement (OR = 1.74; 95% CI: 0.55-5.45) between propolis and miconazole. Most of the included studies showed that phytomedicines had fewer side effects and more patient satisfaction than antifungals or disinfectants. However, further RCTs with more standardly prepared herbal formulations are required to verify the clinical efficacy of phytotherapy as an alternative or adjunctive therapy for denture stomatitis.