Effect of antimicrobial photodynamic therapy with red led and methylene blue on the reduction of halitosis: controlled microbiological clinical trial

Evaluation of the Oral Microbiome before and after Treatments for Halitosis with Photodynamic Therapy and Probiotics-Pilot Study

BACKGROUND

To compare photodynamic therapy and the use of probiotics in reducing halitosis assessed through gas chromatography and microbiome analysis.

METHODS

Participants aged from 18 to 25 years showing sulfide (SH2) ≥ 112 ppb on gas chromatography were selected. They were divided into four treatment groups: Group 1-Tongue Scraping; Group 2-Antimicrobial Photodynamic Therapy (aPDT); Group 3-Probiotics; and Group 4-Antimicrobial Photodynamic Therapy (aPDT) and Probiotics. The halimetry process was performed before, immediately after the treatments, and 7 days, 14 days, and 30 days after the initial collection. The collections for later microbiological analysis were made along with the halimetry for microbiome analysis.

RESULTS

Treatment with aPDT or probiotics under these experimental conditions was not able to change the bacteria present in the biofilm of the tongue.

CONCLUSIONS

More research is needed to know the behavior of the oral microbiome in the presence of halitosis and the effectiveness of new treatments.

In vitro photoinactivation effectiveness of a portable LED device aimed for intranasal photodisinfection and a photosensitizer formulation comprising methylene blue and potassium iodide against bacterial, fungal, and viral respiratory pathogens

Antimicrobial photodynamic therapy (aPDT) can be a viable option for management of intranasal infections. However, there are light delivery, fluence, and photosensitizer-related challenges. We report in vitro effectiveness of an easily fabricated, low-cost, portable, LED device and a formulation comprising methylene blue (MB) and potassium iodide (KI) for photoinactivation of pathogens of the nasal cavity, namely, methicillin-resistant Staphylococcus aureus, antibiotic-resistant Klebsiella pneumoniae, multi-antibiotic-resistant Pseudomonas aeruginosa, Candida spp., and SARS-CoV-2.In a 96-well plate, microbial suspensions incubated with 0.005% MB alone or MB and KI formulation were exposed to different red light (~ 660 ± 25 nm) fluence using the LED device fitted to each well. Survival loss in bacteria and fungi was quantified using colony-forming unit assay, and SARS-CoV-2 photodamage was assessed by RT-PCR.The results suggest that KI addition to MB leads to KI concentration-dependent potentiation (up to ~ 5 log10) of photoinactivation in bacteria and fungi. aPDT in the presence of 25 or 50 mM KI shows the following photoinactivation trend; Gm + ve bacteria  > Gm - ve bacteria > fungi  > virus. aPDT in the presence of 100 mM KI, using 3- or 5-min red light exposure, results in complete eradication of bacteria or fungi, respectively. For SARS-CoV-2, aPDT using MB-KI leads to a ~ 6.5 increase in cycle threshold value.The results demonstrate the photoinactivation effectiveness of the device and MB-KI formulation, which may be helpful in designing of an optimized protocol for future intranasal photoinactivation studies in clinical settings.

Antimicrobial photodynamic therapy for the treatment of oral infections: A systematic review

Oral infection is a common clinical symptom. While antibiotics are widely employed as the primary treatment for oral diseases, the emergence of drug-resistant bacteria has necessitated the exploration of alternative therapeutic approaches. One such modality is antimicrobial photodynamic therapy (aPDT), which utilizes light and photosensitizers. Indeed, aPDT has been used alone or in combination with other treatment options dealing with periodontal disease for the elimination of biofilms from bacterial community to achieve bone formation and/or tissue regeneration. In this review article, in addition to factors affecting the efficacy of aPDT, various photosensitizers, the latest technology and perspectives on aPDT are discussed in detail. More importantly, the article emphasizes the novel design and clinical applications of photosensitizers, as well as the synergistic effects of chemical and biomolecules with aPDT to achieve the complete eradication of biofilms and even enhance the biological performance of tissues surrounding the treated oral area.

The role of the light source in antimicrobial photodynamic therapy

Antimicrobial photodynamic therapy (APDT) is a promising approach to fight the growing problem of antimicrobial resistance that threatens health care, food security and agriculture. APDT uses light to excite a light-activated chemical (photosensitiser), leading to the generation of reactive oxygen species (ROS). Many APDT studies confirm its efficacy in vitro and in vivo against bacteria, fungi, viruses and parasites. However, the development of the field is focused on exploring potential targets and developing new photosensitisers. The role of light, a crucial element for ROS production, has been neglected. What are the main parameters essential for effective photosensitiser activation? Does an optimal light radiant exposure exist? And finally, which light source is best? Many reports have described the promising antibacterial effects of APDT in vitro, however, its application in vivo, especially in clinical settings remains very limited. The restricted availability may partially be due to a lack of standard conditions or protocols, arising from the diversity of selected photosensitising agents (PS), variable testing conditions including light sources used for PS activation and methods of measuring anti-bacterial activity and their effectiveness in treating bacterial infections. We thus sought to systematically review and examine the evidence from existing studies on APDT associated with the light source used. We show how the reduction of pathogens depends on the light source applied, radiant exposure and irradiance of light used, and type of pathogen, and so critically appraise the current state of development of APDT and areas to be addressed in future studies. We anticipate that further standardisation of the experimental conditions will help the field advance, and suggest key optical and biological parameters that should be reported in all APDT studies. More in vivo and clinical studies are needed and are expected to be facilitated by advances in light sources, leading to APDT becoming a sustainable, alternative therapeutic option for bacterial and other microbial infections in the future.

Clinical efficacy of photodynamic therapy on halitosis: a systematic review and meta-analysis

Halitosis is a widespread health problem with complex factors, and therapeutic effects sometimes are unsatisfactory. Plenty of clinical trials have tried to prove the effectiveness of photodynamic therapy (PDT), but the results are indeterminate. This study aimed to evaluate the clinical efficacy of PDT on halitosis. We searched PubMed, Cochrane Library, Embase, Web of Science, and Scopus from inception to August 10, 2022, and only studies about the PDT on halitosis were included. The criteria for meta-analysis comprised randomized controlled trials (RCTs) comparing the treatment of PDT with tongue scraper (TS) immediately after the halitosis therapy and during a 7-, 14-, 30-, and 90-day follow-up. Eight eligible studies involving 345 patients were included in this study. It was shown that PDT (MD =  - 34.49, 95% CI [- 66.34, - 2.64], P = 0.03) or PDT + TS (MD =  - 67.72, 95% CI [- 101.17, - 34.28], P < 0.001) had better efficacy than TS on the H2S concentration reduction immediately after the halitosis therapy. No significant differences were observed in reducing the H2S among TS, PDT alone, and PDT + TS at the follow-up. Besides, no difference between PDT and TS was found in the reduction of CH3SCH3 and CH3SH. Based on the current evidence, PDT and PDT + TS demonstrate efficacy in the treatment of halitosis in the short term, and PDT was shown to be a beneficial and promising therapeutic method.

Effect of Photodynamic Therapy on Halitosis: A Systematic Review of Randomized Controlled Trials

BACKGROUND

This systematic review aimed to assess the effectiveness and safety of aPDT for the treatment of halitosis.

METHODS

Search strategies were conducted in October 2021 without language or data restrictions, on the following databases: MEDLINE, EMBASE, CENTRAL, LILACS and BBO, as well as a manual search. Randomized clinical trials (RCTs) with parallel design were considered for inclusion, assessing individuals (adolescents and adults) with a clinical diagnosis of halitosis treated with photodynamic therapy (aPDT). Primary outcomes assessed were halitosis measurements, adverse events and quality of life. The risk of bias for each included study was evaluated with the Cochrane Risk of Bias tool and the certainty of the body of the evidence was assessed with the GRADe approach.

RESULTS

Six RCTs (total of 225 participants) were included and due to clinical diversities it was not possible to group the outcome data in meta-analyses. Based on very low-certainty evidence (GRADE) the results showed that, when compared to tongue scraper, aPDT seems to promote a little to no difference in reducing halitosis and in the microbiological analysis. No adverse events were reported. Considering aPDT combined with tongue scraper, better outcome results were observed when compared to tongue scraper alone.

CONCLUSIONS

Based on very low-certainty evidence, the findings of this review are uncertain about the effects of aPDT for halitosis control. Further RCTs with higher number of participants and long term assessments need to be conducted to support the use of this intervention. The protocol was registered in the PROSPERO database (number: CRD42020215319) on 19 November 2020-retrospectively registered.

The Problem of Halitosis in Prosthetic Dentistry, and New Approaches to Its Treatment: A Literature Review

The aim of this work is a review of recent scientific literature about intra-oral halitosis among patients using dentures. Halitosis is a condition in which an unpleasant smell comes out of the oral cavity, which is caused mainly by volatile sulfur and non-sulfured compounds. The etiology of halitosis may be intra- or extra-oral; in most patients, however, it is due to the activity of microorganisms in the oral cavity. The problem of the occurrence of intra-oral halitosis has accompanied patients for many years. In dental prosthetics, the problem of halitosis occurs in patients using removable or fixed dentures. In both cases, new niches for the development of microorganisms may be created, including those related to intra-oral halitosis. It should be noted that dentures—both fixed and removable—are a foreign body placed in the patient’s oral cavity which, in case of insufficient hygiene, may constitute a reservoir of microorganisms, causing this unpleasant condition. Conventional treatment of intraoral halitosis reduces microbial activity via chemical and/or mechanical action. Currently, the search for new strategies in the treatment of halitosis is in progress. One idea is to use photodynamic therapy, while another is to modify poly(methyl methacrylate) (PMMA) with silver and graphene nanoparticles. Additionally, attempts have been made to combine those two methods. Another unconventional method of treating halitosis is the use of probiotics.