Evaluation of Antimicrobial Photodynamic Therapy Using Indocyanine Green and Near-Infrared Diode Laser AgainstEnterococcus faecalisin Infected Human Root Canals

Stimuli-responsive materials in oral diseases: a review

OBJECTIVES

Oral diseases, such as dental caries, periodontitis, and oral cancers, are highly prevalent worldwide. Many oral diseases are typically associated with bacterial infections or the proliferation of malignant cells, and they are usually located superficially.

MATERIALS AND METHODS

Articles were retrieved from PubMed/Medline, Web of Science. All studies focusing on stimuli-responsive materials in oral diseases were included and carefully evaluated.

RESULTS

Stimulus-responsive materials are innovative materials that selectively undergo structural changes and trigger drug release based on shifts at the molecular level, such as changes in pH, electric field, magnetic field, or light in the surrounding environment. These changes lead to alterations in the properties of the materials at the macro- or microscopic level. Consequently, stimuli-responsive materials are particularly suitable for treating superficial site diseases and have found extensive applications in antibacterial and anticancer therapies. These characteristics make them convenient and effective for addressing oral diseases.

CONCLUSIONS

This review aimed to summarize the classification, mechanism of action, and application of stimuli-responsive materials in the treatment of oral diseases, point out the existing limitations, and speculate the prospects for clinical applications.

CLINICAL RELEVANCE

Our findings may provide useful information of stimuli-responsive materials in oral diseases for dental clinicians.

The Effect of Photodynamic Therapy on Enterococcus spp. and Its Application in Dentistry: A Scoping Review

Enterococci spp. are Gram-positive bacteria that cause mild to severe infections, many associated with the oral cavity, such as periapical infections and healthcare-associated infections (HAIs). Many of these infections become serious diseases that are difficult to resolve, specifically when multidrug-resistant (MDR) strains cause them. In recent years, the number of MDR strains of Enterococcus spp. has increased significantly. This increased prevalence of MDR strains produces significant pressure to generate more antimicrobial therapies, but there is a decline in the production of new antibiotics, driving the development of complementary therapies, such as photodynamic therapy (PDT). PDT combines a photosensitizer agent (PS), light, and oxygen to cause photooxidative stress in bacterial cells. PDT can eradicate Enterococcus spp. contaminations, improve the classic cleaning processes, and eradicate the bacteria in dental pieces. PDT's effectiveness can be improved with nanoparticles that function as carriers. Our work aims to describe the advances in PDT against Enterococcus spp. as a complement to antibiotic therapy, focusing on infections by Enterococcus faecium and Enterococcus faecalis, dental hygiene, and using nanoparticles to improve the antimicrobial effect. A systematic bibliographic search without a meta-analysis was conducted on various databases, using inclusion and exclusion criteria to identify the most relevant research. Of the 193 non-redundant articles found, 65 were selected for a systematic review, from which a summary table was created and a manual description was made. Photodynamic therapy for treating E. faecium and E. faecalis is a widely studied area, with promising results concerning bactericidal effectiveness and reductions in biofilm formation, particularly in regard to dental hygiene. Because most of the studies were conducted in vitro or ex vivo, the results indicated that there were not sufficient data to initiate clinical trials for safety and efficacy studies on humans.

The Evaluation of SWEEPS Plus Antimicrobial Photodynamic Therapy with Indocyanine Green in Eliminating Enterococcus faecalis Biofilm from Infected Root Canals: An In Vitro Study

OBJECTIVES

This study aimed to assess the efficacy of shockwave-enhanced emission photoacoustic streaming (SWEEPS) plus antimicrobial photodynamic therapy (aPDT) using indocyanine green (ICG) for the elimination of Enterococcus faecalis biofilm from infected root canals.

MATERIALS AND METHODS

thirty sound human single-canal teeth were chosen and standardized to have 12 mm of root length. The root canals were shaped and prepared by means of ProTaper rotary files. After sterilization of the teeth, the canals were inoculated with E. faecalis for 2 weeks. The teeth were then randomly divided into six groups (n = five) of control, ICG, ICG + 808 nm diode laser, ICG + SWEEPS, ICG + 808 nm diode laser + SWEEPS, and 5.25% sodium hypochlorite (NaOCl). Following treatment, the number of colony-forming units (CFUs)/mL were calculated for each group. Statistical analysis was carried out using one-way ANOVA. For multiple comparisons, Tukey's test was used as the post hoc test.

RESULTS

NaOCl alone showed the highest efficacy (p < 0.001). The ICG + 808 nm diode laser + SWEEPS group displayed significantly lower amounts of bacteria than either the ICG + 808 nm diode laser or SWEEPS (p < 0.001). There was a statistically significant difference detected between the ICG + 808 nm diode laser and ICG + SWEEPS (p = 0.035).

CONCLUSIONS

SWEEPS can effectively increase the photosensitizer distribution in the root canal space, and its application along with irrigants can bring about promising results.

Effectiveness of final cavity disinfectant Terminalia chebula, Malachite, and Indocyanine green, against E. faecalis and on the bond interface of fiber post to radicular dentin

AIMS

Evaluation of antimicrobial efficacy of contemporary disinfection Malachite green (MG), Terminalia chebula (T. chebula), and Indocyanine green (ICG)) against E. faecalis and their effect on push-out bond strength (PBS) of glass fiber post (GFP) bonded to root dentin in comparison to conventional irrigation used (Sodium hypochlorite (NaOCl) + Ethylene diamine tetraacetic acid (17% EDTA).

MATERIALS AND METHODS

Root canal treatment was initiated on sixty human single-rooted premolars and working length was established. The canals were enlarged using ProTaper universal system till F3. The prepared canals were obturated with Gutta-percha (GP) and AH Plus sealer followed by post-space preparation. Twenty canals contained a standard strain of E. faecalis (n=5 in each group) cultured overnight at 37 °C in BHI broth. All the samples were randomly allocated into four groups based on post-space irrigation. (n = 10) Group 1: 5.25% NaOCl+17% EDTA (Control), Group 2: 5.25% NaOCl + ICG, Group 3: 5.25% NaOCl + MG and Group 4: 5.25% NaOCl + T. chebula. Survival rates of E. faecalis were evaluated on the twenty specimens. GFP was placed on the remaining samples using self-etch dual-cure pastes and sectioning was performed in 1 mm thick slices. PBS and failure mode were analyzed using a universal testing machine and stereomicroscope. One-way analysis of variance (ANOVA) and Tukey multiple comparison t-tests were used for data analysis. (p = 0.05).

RESULTS

5.25% NaOCl+17% EDTA demonstrated (0.11±0.01 CFU/mL) the lowest survival rate of E. faecalis. However, Group 2 (5.25% NaOCl + ICG) exhibited the highest survival rate (0.52 ± 0.10). Furthermore, the coronal third of group 4 (5.25% NaOCl + T. chebula) (8.71±0.25 MPa) specimens demonstrated the highest PBS of GFP. However, an apical section of group 2 samples (5.25% NaOCl + ICG) (1.21±0.71 MPa) displayed the lowest outcome of bond integrity.

CONCLUSION

Terminalia chebula when used as a final canal disinfectant seems to be promising in improving canal sterility and the bond strength of GFP to the root dentin.

Antibacterial Effect of Red Laser Therapy on Enterococcus faecalis Using Different Photosensitizers: An In Vitro Study

Objective

To assess the antibacterial effect of red laser using different photosensitizers such as methylene blue and malachite green on monoradicular premolars contaminated with E. faecalis ATCC 29212.

Methods

This was an in vitro experimental study. Monoradicular premolars (44, 45, 34, and 35) were used, which were treated with ProTaper Next. After instrument change, irrigation, disinfection, and aspiration were performed with 2 ml of 4% NaOCl with a NaviTip 30°G needle (Ultradent, South Jordan, UT, USA). Group 1: RL + MB (red laser associated with methylene blue photosensitizer), group 2: RL + MG (red laser associated with malachite green photosensitizer), and group 3: control (no treatment). The E. faecalis strain was cultured on trypticase soy agar (TSB) (Difco, Detroit, MI, USA) and incubated at 37°C for 24 h. After the incubation period, colony-forming units (CFU/ml) of each group were counted using the plate count method. The ANOVA test was used with a significance level of p < 0.05.

Results

Group 1 had the lowest antibacterial contamination as it averaged only 530 ± 581.3 CFU/ml, while group 2 had the highest contamination with an average of 1990 ± 542.5 CFU/ml. Comparison revealed that there were statistically significant differences between the RL + MB and RL + MG groups (p < 0.001).

Conclusions

Group 1 had the best antimicrobial potential because it presented the lowest contamination in CFU/ml of E. faecalis compared to group 2 and group 3.

Antimicrobial action of photodynamic therapy on Enterococcus faecalis biofilm using curing light, curcumin and riboflavin

The aim of this study was to assess the effect of antimicrobial photodynamic therapy (aPDT) with curcumin and riboflavin on three-week Enterococcus faecalis biofilm. At first the 15-mm root canals of 65 single rooted extracted human teeth (including maxillary incisors, mandibular and maxillary canines and mandibular premolars) were separated from the crown and were prepared with ProTaper instruments. After autoclave sterilisation, samples were inoculated with E. faecalis suspension, and incubated for three weeks. After ensuring biofilm formation by scanning electron microscopy (SEM) in two teeth, the remaining 63 teeth were randomly divided into seven groups (n = 9): aPDT + curcumin, aPDT + riboflavin, LED, curcumin, riboflavin, 5.25% NaOCl (positive control) and no intervention (negative control). For light source a LED unit with 390-480 nm wavelength (peak of 460 nm), power density of 1000 ± 100 mW cm^-2 and mean energy density of 60 J cm^-2 was used. The roots were horizontally sectioned into coronal, middle and apical thirds each with 5 mm thicknesses. Dentin chips with equal weight (1 ± 0.005 g) were collected from the root canal walls with Gates Glidden drills and were transferred into microtubes containing 1 mL of sterile saline and vortexed for 30 s. Next, 10 µL of the contents of each tube was serially diluted and eventually, 10 µL of each solution was cultured on BHI agar. The number of colony-forming units was determined. Data were analysed using the Kruskal-Wallis and Friedman tests. The colony reduction was not significantly different between NaOCl and either riboflavin + LED or Curcumin + LED. The 5.25% NaOCl group showed maximum reduction in colony count, compared with the negative control (P = 0.00). Groups with aPDT with Curcumin + LED (P = 0.005), and with riboflavin + LED (P = 0.011) showed significant reduction in colony count in all three canal thirds (P < 0.05) without any difference with one another. With significant reduction of E. faecalis colony count, aPDT with Curcumin and riboflavin can serve as an adjunct to routine root canal disinfection method.

Effectiveness of antimicrobial photodynamic therapy with indocyanine green against the standard and fluconazole-resistant Candida albicans

Antimicrobial photodynamic therapy (aPDT) is an alternative approach. The current study aimed to investigate the efficacy of aPDT with indocyanine green (ICG) against two Candida albicans (C. albicans) strains. In this in vitro study, the inoculum of standard ATCC 10,231 (S) and fluconazole-resistant (FR) strains were adjusted to the turbidity of a 0.5 McFarland standard. Each strain was allocated into 4 groups: S1 and FR1) control groups, S2 and FR2) ICG-treated groups (1 µg/mL), S3 and FR3) laser-irradiated groups (wavelength: 810 nm; mode: continuous-wave; output power: 300 mW; spot size: 4.5 mm; exposure time: 120 s; radiation dose: 228 J/cm²), S4 and FR4) ICG-mediated-aPDT groups. After treatments, the number of colony-forming units per milliliter (CFU/mL) was calculated. Using the XTT reduction assay, the effects of each treatment on Candida biofilm formation were evaluated. Data were analyzed using SPSS software version 22. In both strains, the maximum number of CFUs was observed in the control group, followed by ICG-treated, laser-irradiated, and ICG-mediated-aPDT groups. In ATCC 10,231 strain, the XTT assay exhibited significant difference between ICG-mediated-aPDT and control groups (p < 0.0001). However, the ICG, laser, and ICG-mediated-aPDT groups in fluconazole-resistant strain showed significant differences when compared with the control (p < 0.05). The mean Candida CFUs and the XTT assay did not show any significant difference between the ATCC 10,231 and fluconazole-resistant strains with respect to each treatment. Data suggest ICG-mediated-aPDT could diminish Candida CFUs in laboratory; however, further studies are warranted to confirm its efficacy and safety to be applied in clinics.

Optimization of antibacterial therapy in patients with endo-periodontal lesions

To improve the quality and effectiveness of medical care for patients with inflammatory periodontal diseases, it is necessary to search for new approaches in both diagnosis and treatment. The aim of our study is to determine the effect of the diode laser on the pathogenic microflora of periodontal pockets and root canals in patients with endo-periodontal lesions (EPL). We carried out a comparative assessment of the bacterial contents of the root canals and periodontal pockets by polymerase chain reaction (PCR) before and after treatment with a diode laser (Doctor Smile Simpler, wavelength 980 nm) for 54 patients with EPL. The control group consisted of 56 patients who were treated according to the generally accepted method, including professional oral hygiene, endodontic treatment, and curettage of periodontal pockets. Evaluation criteria were a qualitative assessment of the content of periodontopathogens in the root canal and periodontal pocket before and after and treatment. As a result of our study, we found a statistically significant (p<0.01) reduction in the colonization of periodontal pockets and root canals in patients with EPL after laser decontamination. The high technological effectiveness of the methods used in combination with the low risk of complications at the stages of endodontic and periodontological treatment provides an antibacterial effect and reduces the duration of inflammation. The results of treatment of patients using a diode laser give reason to recommend their use in the dental practice.

Biofilm Inactivation using Photodynamic Therapy in Dentistry: a review of literature

Introduction: Photodynamic therapy (PDT) is a therapy involving light and a photosensitising chemical substance, used in conjunction with molecular oxygen in order to elicit cell death (photo-toxicity) and thus ability to kill microbial cells, including bacteria, fungi and viruses. Photodynamic therapy is an alternative method of biofilm disruption and it is considered a new way of microorganism inactivation. It is also an additional procedure to reduce the infection rate in patients, caused by the increasing antimicrobials resistance of bacteria. The aim of this literature review was to evaluate the specific effects and the antibacterial effectiveness of photodynamic therapy using different types of photosensitizers (Erythrosine, Rose Bengal, Toluidine blue, Methylene blue, Ozone, Riboflavin, Curcumin, Chlorhexidine, SAPYR) and a visible light of a specific wavelength for each photosensitizer and to reveal the applications of PDT in periodontics, endodontics, prosthodontics and dental caries. Methods: A research of literature was performed in an attempt to find all the articles published on this topic in the last 10 years. The articles was searched by using a certain combination of different keywords (photodynamic therapy ) and (diode laser ) and (teeth) in PubMed database. Results: A total number of 83 articles were found. After applying inclusion and exclusion criteria, 35 articles were taken into consideration for our study and among them 4 were a manuscript, 3 was a review of literature, 1 was an in vivo evaluation and 27 were in vitro studies. Conclusion: Considering that none of the disinfection methods can completely remove the biofilm, PDT is a therapeutic tool complementary to conventional disinfection, with great applicability in dentistry. PDT showed significantly efficacy in reduction of biofilms. Exposure to light in the presence of a photosensitizing chemical substance helps in the reduction of microbes and the protocols could be recommended for clinical usage, but only together with ‘classic ‘ disinfection.

Simultaneous photoablative and photodynamic 810-nm diode laser therapy as an adjunct to non-surgical periodontal treatment: an in-vitro study

BACKGROUND

The use of lasers at different wavelengths has been proposed in combination with conventional non-surgical periodontal treatment in order to improve the clinical outcome of periodontal disease. However, the clinical use of laser photonic energy is still the subject of research and debate because the antibacterial activity of the laser is dependent upon method, laser parameters, quantity of bacteria, species selected and photosensitizers used.

METHODS

We evaluated the in-vitro bactericidal activity of 810 nm diode-laser irradiation in simultaneous photoablative and photodynamic mode against the major pathogenic bacterial organisms associated with periodontal inflammation and disease. We used indocyanine green as photosensitizer and the high-energy density of 161.7 J/cm2 or 215.0 J/cm2 for the photoablative-photodynamic irradiation.

RESULTS

The bacteria were drastically affected by the 215.0 J/cm2 irradiation in the presence of indocyanine green. In fact, the number of Porphyromonas gingivalis and Prevotella intermedia was reduced by 99.9% (P<0.001), while the number of Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, Tannerella forsythia and Actinomyces viscosus decremented by 83.3% (P<0.01), 86.8% (P<0.05), 75% (P<0.01) and 78.7% (P<0.001), respectively. P. gingivalis and P. intermedia were the only bacteria that were sensitive to the treatment with indocyanine green dye and 161.7 J/cm2 of laser irradiation (P<0.001).

CONCLUSIONS

Our preliminary in-vitro data suggest that simultaneous photoablative-photodynamic irradiation could be a promising therapy against a wide range of bacteria involved in periodontal disease. We believe that further additional in-vivo investigation is necessary, to enable a more complete picture of effectiveness within a clinical setting to be established. In addition, the use of a simultaneous photoablative-photodynamic therapy is suggested to reduce treatment time, without compromising the efficacy against the periodontal pathogens.

Photoelimination Potential of Chitosan Nanoparticles-Indocyanine Green Complex Against the Biological Activities of Acinetobacter baumannii Strains: A Preliminary In Vitro Study in Burn Wound Infections

Introduction: Acinetobacter baumannii strains are important agents causing serious nosocomial infections including soft-tissue and skin infections in patients with burn wounds which have become resistant to several classes of antibiotics. Antimicrobial photodynamic therapy (aPDT) as an alternative antimicrobial procedure is suggested for the treatment of these kinds of infections. The aim of the current study is to evaluate the antibacterial and anti-biofilm efficiency of aPDT by the utilization of an improved form of indocyanine green (ICG) which is encapsulated in chitosan nanoparticles (NCs@ICG). Methods: NCs@ICG were synthesized and confirmed by the scanning electron microscope (SEM). aPDT was performed using NCs@ICG with an 810 nm wavelength of the diode laser at the fluency of 31.2 J/cm² on 50 A. baumannii strains isolated from burn wounds. The antibacterial and antibiofilm potential of NCs@ICG-aPDT was determined via the colony forming unit (CFU)/mL and crystal violet assays, respectively. In addition, microbial biofilm degradation was evaluated by the SEM. Results: According to the results, NCs@ICG-aPDT showed a significant reduction of 93.2% on the CFU/ mL of planktonic A. baumannii strains compared to the control group (untreated group; P < 0.05). In addition, the biofilm formation of A. baumannii strains was significantly reduced by 55.3% when the bacteria were exposed to NCs@ICG-aPDT (P < 0.05). In contrast, NCs@ICG, ICG, and the diode laser alone were not able to inhibit the CFU/mL and biofilm of A. baumannii strains (P > 0.05). Based on the results of SEM images, NCs@ICG-aPDT disrupted the biofilm structure of A. baumannii strains more than other groups. Conclusion: NCs@ICG-aPDT demonstrates a promising treatment candidate for exploitation in wound infections against both planktonic and biofilm forms of A. baumannii strains.

Inactivation of oral biofilms using visible light and water-filtered infrared A radiation and indocyanine green

Aim: To investigate the antimicrobial photodynamic therapy (aPDT) of visible light and water-filtered infrared A radiation in combination with indocyanine green (ICG) on planktonic oral microorganisms as well as on oral biofilm. Methods: The irradiation was conducted for 5 min in combination with ICG. Treatment with chlorhexidine served as a positive control. The number of colony forming units and bacterial vitality were quantified. Results: All tested bacterial strains and salivary bacteria were killed at a level of 3log_10. The colony forming units of the initial mature oral biofilms were strongly reduced. The high bactericidal effect of aPDT was confirmed by live/dead staining. Conclusion: The aPDT using visible light and water-filtered infrared A radiation and ICG has the potential to treat periodontitis and peri-implantitis.

Comparison of the efficacy of low-level laser therapy and photodynamic therapy on oral mucositis in rats

Cancer treatment with chemotherapy or radiotherapy is associated with some side effects including in the oral cavity. One of the more significant oral complications is oral mucositis (OM) which induces severe pain and limits fundamental life behaviors such as eating, drinking, and talking. Although advancements in cancer treatment improved the survival rate, severe OM and opportunistic infection affect treatment adversely. Therefore, the control of OM is important for oral health quality of life and prognosis. Low-level laser therapy (LLLT) and photodynamic therapy (PT) are noninvasive methods that reduce inflammation and pain during wound healing. The aim of this study is to evaluate immunohistochemical and histological examination of the OM region of the PT comparing LLLT. In this study, 24 Sprague-Dawley rats were divided into three groups as control, LLLT, and PT groups. All groups received 5-fluorouracil intraperitoneally and a linear trauma to the mouth pouch with a needle. After the formation of OM in the mouth, the control group had no treatment; the LLLT group was administered LLLT, and the PT group had LLLT after indocyanine green application. Then all groups were sacrificed, and histological analyses and protein level detection of basic fibroblast growth factor (bFGF), transforming growth factor (TGF-β), and platelet-derived growth factor (PDGF-BB) were evaluated in all groups. PT was determined to be more statistically significantly than LLLT with bFGF and PDGF-BB. However, regarding TGF-β, no statistically significant difference was observed between the groups. Within the limitations of this study, indocyanine green may accelerate the LLLT effect. However, further studies on this subject are required.