Efficacy Of Antimicrobial Photodynamic Therapy Research Articles

Efficacy of antimicrobial photodynamic therapy with chloro-aluminum phthalocyanine on periodontal clinical parameters and salivary GSH and MDA levels in patients with periodontitis.

The purpose of this study was to evaluate the efficacy of antimicrobial photodynamic therapy (aPDT) with chloro-aluminum phthalocyanine (AlClPc) on several periodontal parameters includingsalivary glutathione (GSH) and MDA (malondialdehyde) levels in periodontal sites presenting with periodontitis. Randomized clinical trial, comprising 40 test group (TG) sites and 23 control group (CG) sites. The TG was treated with scaling and root planning (SRP) and aPDT, and CG, only with SRP. Visible plaque index [VPI], gingival bleeding index [GBI], bleeding on probing [BOP], probing depth [PD] and clinical attachment level [CAL] were calculated and saliva samples were taken at baseline (T0), three (T3) and six months (T6). Data was analyzed by the Wilcoxon and Mann-Whitney tests. An intragroup analysis indicated significant differences at T3 and T6 for GBI, CAL and GSH only in the CG (p < 0.05). For BOP, a significant decrease was observed only in the TG between T0 and T6 (p = 0.008). No significant differences were observed for VPI, BOP and MDA. In the intergroup analysis, significant differences were observed for GBI at T6 (p = 0.041), and for GSH at T3 (p = 0.031), being higher in the TG. Although aPDT with AlClPc did not present statistically proven benefits, but the employed periodontal treatment resulted in decreased BOP, PD, CAL and MDA after 3 and 6 months of treatment. In addition, the lower need for glutathione production may initially suggest an additional benefit of AlClPc aPDT in the early reestablishment of the balance between oxidative and non-oxidative agents related to oxidative stress.

Photodynamic inactivation of methicillin-resistant Staphylococcus aureus on skin using a porphyrinic formulation.

Staphylococcus aureus is responsible for skin and soft tissue infections. Having in mind increased antibiotic resistance, in this study the efficacy of antimicrobial photodynamic therapy (aPDT) with a porphyrinic formulation (FORM) as photosensitizer (PS) to photoinactivate methicillin-resistant Staphylococcus aureus (MRSA) on skin was evaluated. Potassium iodide (KI) and iodopovidone (PVP-I) were also tested in combination with FORM as potentiator agents of FORM efficacy. The aPDT protocol was first developed in Phosphate Buffered Saline (PBS, in vitro). Porcine skin was artificially contaminated with MRSA (ex vivo) and treated with FORM, FORM + KI or FORM + PVP-I under white light. The in vitro results showed that FORM was effective to inactivate MRSA. A substantial reduction in the irradiation time, when compared to FORM alone, was observed for FORM + KI and FORM + PVP-I combinations. On skin, reductions in MRSA survival of 3.1 Log10 colony forming units (CFU) mL-1 were observed with FORM at 50 μM. Although the combined action of FORM + KI and FORM + PVP-I potentiated the aPDT efficacy in vitro, this was not observed ex vivo. Overall, the results showed that aPDT using FORM, even without coadjutants, is a promising approach for MRSA inactivation on skin.

Effectiveness of a single treatment of photodynamic therapy using topical administration of 5-aminolevulinic acid on methicillin-resistant Staphylococcus aureus-infected wounds of diabetic mice

Methicillin-resistant Staphylococcus aureus (MRSA) is the most important representative pathogen which causes clinically relevant infections in diabetic ulceration. We report our investigations on the efficacy of antimicrobial photodynamic therapy with topical 5-aminolevulinic acid (ALA-PDT) on diabetic murine infected wound models induced with a MRSA SA325 strain. A solution of 10 % 5-aminolevulinic acid (ALA) was placed into the wounds followed by delivery of 25 J/cm2 (635 nm). The ALA-PDT treated wounds healed earlier as compared to others (P < 0.5). A significant reduction of bacterial counts (2.05 logs) was detected in wounds after ALA-PDT on Day 2 (P < 0.5). Additionally, histological analysis revealed that wounds treated with ALA-PDT exhibited a more complete re-epithelialization, blood micro-vessels, collagen-volume fraction and considerable decrease in inflammatory cells infiltration. Immunohistochemistry assay demonstrated considerable reduction of proinflammatory cytokines interleukin-1β (IL-1β), earlier expression of vascular endothelial growth factor A (VEGF-A), increase of basic fibroblast growth factor (bFGF) and Ki-67 in the ALA-PDT group (P < 0.5). These data imply that the therapeutic effect of ALA-PDT revealed an accelerated diabetic wound closure rate, together with reduced hyperinflammatory response and elevated growth factors.

Antimicrobial photodynamic therapy effectiveness against susceptible and methicillin-resistant Staphylococcus aureus biofilms

Staphylococcus aureus have a great ability to become rapidly resistant to conventional antimicrobial therapies. This study evaluated the efficacy of antimicrobial photodynamic therapy (aPDT) mediated by Curcumin (Cur) and light-emitting diode (LED) in the inactivation of biofilms of methicillin susceptible and resistant S. aureus (MSSA and MRSA, respectively). Biofilms were treated with Cur (20, 40 or 80 μM) and illuminated with LED source (455 ± 3 nm; 5.28 J/cm2) (aPDT groups), or treated either with Cur or LED only. Other samples were not exposed to Cur or LED (negative control). The biofilms viability after all experimental conditions were evaluated by counting the number of colonies (CFU/mL) and XTT assay. Additional samples were also evaluated by LIVE/DEAD® staining using confocal laser scanning microscopy (CLSM). Data were analyzed by ANOVAs followed by the Games-Howell post hoc test (α = 0.05). For both strains, all aPDT groups significantly reduced both CFU/mL and metabolic activity of biofilms compared to the negative control (p < 0.001). The results were enhanced when 80 μM of Cur was used. CLSM images showed that both bacteria biofilms submitted to aPDT had a large number of red-stained colonies, especially at aPDT80. In general, MRSA biofilms tended to be less susceptible to aPDT than MSSA biofilms. It can be concluded that aPDT mediated by Cur and LED was an efficient method to inactivate 48 -h biofilms of both S. aureus strains.

Antimicrobial efficacy of photodynamic therapy on the treatment of oral candidiasis in people living with hiv/aids

Objetivo: Avaliar a eficácia antimicrobiana da terapia fotodinâmica no tratamento da candidíase oral em pessoas vivendo com HIV/aids. Método: Estudo experimental, qualitativo e descritivo com 18 pessoas vivendo com HIV/aids que manifestavam a candidíase oral, maiores de 18 anos, que estavam em tratamento no Hospital Universitário Gaffrée e Guinle. Este grupo subdividiu-se em um grupo controle, composto por sete pessoas, que recebeu tratamento com a terapia fotodinâmica e antifúngicos, e um grupo experimental, com 11, que recebeu apenas a terapia fotodinâmica. A evolução do tratamento de cada participante foi acompanhada por registros fotográficos em duas consultas, inicial e final. Esta pesquisa foi aprovada pelo Comitê de Ética em Pesquisa do hospital, parecer número 2.431.107. Resultados: A maioria dos participantes apresentou melhora clínica, ainda que discreta, e em apenas um houve piora clínica. Conclusão: A terapia fotodinâmica antimicrobiana pode ser eficaz no tratamento da candidíase oral em pessoas vivendo com HIV/aids.

Antimicrobial photodynamic therapy efficacy against specific pathogenic periodontitis bacterial species.

To determine the safety and efficacy of antimicrobial photodynamic therapy (aPDT) combination of 0.33 mM Toluidine Blue O (TBO) with 60 mW/cm2 LED irradiation for 5 min that we had established, this study investigated the cytotoxic effect of aPDT combination on mammalian oral cells (gingival fibroblast and periodontal ligament cells) and compared the antimicrobial efficacy of antibiotics (the combination of amoxicillin (AMX) and metronidazole (MTZ)) against representative periodontitis pathogenic bacteria (Porphyromonas gingivalis, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans) versus our aPDT combination. aPDT combination did not show any detectable effect on the viability of Streptococcus sanguinis or Streptococcus mitis, the most common resident species in the oral flora. However, it significantly reduced CFU values of P. gingivalis, F. nucleatum, and A. actinomycetemcomitans. The cytotoxicity of the present aPDT combination to mammalian oral cells was comparable to that of standard antiseptics used in oral cavity. In antimicrobial efficacy test, the present aPDT combination showed equivalent bactericidal rate compared to the combination of AMX + MTZ, the most widely used antibiotics in the periodontitis treatment. The bactericidal ability of the AMX + MTZ combination was effective against all five bacteria tested regardless of the bacterial species, whereas the bactericidal ability of the aPDT combination was effective only against P. gingivalis, F. nucleatum, and A. actinomycetemcomitans, the representative periodontitis pathogenic bacterial species. The present study demonstrated the safety and efficacy of the present aPDT combination in periodontitis treatment. TBO-mediated aPDT with LED irradiation has the potential to serve as a safe single or adjunctive antimicrobial procedure for nonsurgical periodontal treatment without damaging adjacent normal oral tissue or resident flora.

Inter-comparison of antimicrobial photodynamic therapy, LASER, and an antifungal agent as adjunct intracanal irrigation techniques to standard disinfection protocols in reducing Candida albicans counts in the root canals of primary teeth: A pilot study

Despite endodontic infections being a common problem in the primary dentition, some of the infected primary teeth can remain functional until the exfoliation through endodontic treatment. The primary endodontic treatment goal must be to optimize root canal disinfection and to prevent reinfection. The aim of this study is to compare the antifungal efficacy of antimicrobial photodynamic therapy, LASER, and 1% clotrimazole as irrigants by reducing the colony-forming units (CFU) of Candida albicans in the infected root canals of primary teeth. Pulp therapy was performed on deciduous mandibular second molars of 20 healthy children aged 5-8 years, which were divided into four groups of intracanal disinfection protocols: Group 1 (n = 5) - Sodium Hypochlorite, Group 2 (n = 5) - Photodynamic, Group 3 (n = 5) - Normal saline with LASER, and Group 4 - (n = 5) Antifungal. Disinfection potential was compared by collecting samples one just after access opening and the other after the experimental groups using paper points. The samples were cultured and incubated for 48 h to check change in CFU of the fungi. Data were analyzed statistically using the Shapiro-Wilk's test, Mann-Whitney U-test; Kruskal-Wallis test, and Wilcoxon signed-ranks test. No significant difference (P > 0.05) was found between the different groups. However, complete inhibition of C. albicans CFU was seen with Group 4. One percent Clotrimazole (antifungal) can be utilized as an adjunct in the endodontic irrigation protocol for better success of pulpectomy in children.

Repeated application of photodynamic and antibiotic therapy as an adjunct to root surface debridement in patients with grade C and stage III or IV aggressive periodontitis.

To evaluate the efficacy of antimicrobial photodynamic therapy (aPDT) and antimicrobial therapy on clinical and immunological outcomes of periodontal treatment in patients with periodontitis grade C and stage III or IV. The patients recruited in the current research fulfil the clinical case definition of periodontitis 'grade C' in terms of onset of the infection and stage III or IV that defines degree and severity of the disease. One-stage full-mouth ultrasonic debridement (UD) was performed and randomly divided in two groups: Group-I - four applications of aPDT, and Group-II - combination of metronidazole (MTZ) and amoxicillin (AMX) 3 tablets each for 7 days. Whole-mouth periodontal parameters were recorded at baseline, 3-, 6-months after completion of treatment. Gingival crevicular fluid samples were obtained for assessment of inflammatory interleukin (IL)-10 and IL-17 at the same time points. Seventeen healthy patients completed the study protocol and revealed similar clinical findings at baseline. Bleeding scores significantly reduced in group-I at 3 months post treatment (p < 0.05). It could be seen that group-I showed statistically significant reduction of deep periodontal pockets and gain in CAL in patients with GAP at 3 months (p < 0.05). This difference was maintained at 6 months of follow-up (p < 0.001). Group-II was capable of increasing the levels of IL-10 and reducing IL-17 in GCF at both time periods compared to Group-I (p < 0.05). Group-I did not have significant effect on either cytokine levels in GCF (p > 0.05). Antimicrobial photodynamic therapy improved severe deep periodontal pockets. However, the combination of antimicrobial therapy helped in reducing proinflammation in grade C and stage III or IV periodontitis.

Antimicrobial efficacy of photodynamic therapy, diode laser, and sodium hypochlorite and their combinations on endodontic pathogens.

Sterilization of the root canal system is of prime importance for a successful root canal therapy. Lasers and photodynamic therapy (PDT) have become the latest choice to eradicate microorganisms in the root canal. To evaluate and compare the antimicrobial activity of diode laser, photodynamic therapy, and sodium hypochlorite along with their combinations on endodontic pathogens: Enterococcus faecalis and Streptococcus mutans. A total of 120 uniradicular teeth were stored in 5.2% NaOCl solution to remove organic residues and the crowns were sectioned at the cemento-enamel junction (CEJ) to obtain root canal length of 15 mm. Canals were shaped using step-back technique up to #40 K-file and were autoclaved. The selected teeth (specimen) were randomly divided into two equal groups with sixty teeth being inoculated with E. faecalis (Group E) and remaining sixty teeth with S. mutans (Group S). Further, the groups were subdivided according to the disinfection technique used. Ten teeth from each subgroup were disinfected with a diode laser, photo activated disinfection (PAD), sodium hypochlorite, a combination of sodium hypochlorite and diode laser, a combination of sodium hypochlorite and photo activated disinfection respectively. Ten teeth in each group served as control without any disinfection. The treated specimens were transferred to test tubes containing 5 ml sterile Luria Bertani broth, incubated and the bacterial count, optical density in each root specimen was calculated and compared. The pairwise comparison of colonies across the subgroups was done by the Kruskal-Wallis test and within the subgroups was carried out using the Mann-Whitney U test. The statistical implication was tested at 5% and the study was performed using SPSS 18.0 ver. (SPSS Inc.). A significant reduction (98%) in the E. faecalis count was observed when the NaOCl was used in combination with the diode laser or PAD. PAD along with 3% NaOCl presents the advantage of utilizing a lower wavelength laser beam. Hence, PAD in combination with NaOCl can be an alternative and better option for root canal disinfection for both the endodontic pathogens, E. faecalis and S. mutans.

The efficacy of antimicrobial photodynamic therapy and light‐activated disinfection on zirconia implants‐ In vitro study

The efficacy of antimicrobial photodynamic therapy and light‐activated disinfection on zirconia implants‐ In vitro study

Clinical efficacy of photodynamic therapy and laser irradiation as an adjunct to open flap debridement in the treatment of chronic periodontitis: A systematic review and meta-analysis.

The aim of this systematic review and meta-analyses was to assess the quality of evidence and efficacy of antimicrobial photodynamic therapy (aPDT) and laser irradiation (LI) as an adjunct to open flap debridement (OFD) in the treatment of chronic periodontitis. Electronic searches were conducted in databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials and Cochrane Oral Health Group Trials Register databases) up to March 2019. Randomized clinical trials (RCTs) comparing clinical efficacy of either aPDT and/or LI, placebo, or no treatment were included. Primary outcomes included clinical attachment level (CAL), while secondary outcomes were reduction in probing depth (PD) and gingival recession (GR) depth. The weighted mean differences (WMD) of outcomes and 95% confidence intervals (CI) for each variable were calculated using random effect model. Six RCTs were included. For aPDT studies, the overall mean difference for CAL gain (WMD=-0.61, 95% CI=-1.22 to -0.016, P=.044) and PD reduction (WMD=-1.79, 95% CI=-3.44 to -0.14, P=.034) was significant between aPDT and OFD groups at follow-up. No significant overall mean difference was observed for GR depth (WMD=0.02, 95% CI=-0.75 to 0.79, P=.95). For LI studies, none of the clinical periodontal parameters including CAL gain (WMD=0.23, 95% CI=-0.09 to 0.55, P=.159, Figure 3A), PD reduction (WMD=0.31, 95% CI=-0.67 to 1.31, P=.52, Figure 3B) and GR depth (WMD=-0.34, 95% CI=-2.47 to 1.78, P=.74, Figure 3C) were found to be significant between LI and OFD groups at follow-up. With the limited data available, only aPDT as an adjunct to OFD showed superior results for clinical periodontal parameters compared to OFD alone in the treatment of chronic periodontitis. Further RCTs are warranted in order to obtain robust conclusions with regard to laser therapy.

Oral microbiological control by photodynamic action in orthodontic patients.

Orthodontics involves diagnosis and treatment of dental and skeletal malocclusions. Orthodontic apparatus may repair these malocclusions but may also impair oral hygiene making patients prone to develop both periodontal diseases and caries. Antimicrobial agents may be used to prevent this.To avoid increased antimicrobial resistance to available drugs, A-PDT (Antimicrobial Photodynamic Therapy) appears as a viable alternative. This work aimed to evaluate the efficacy of A-PDT on reducing the number of colony forming units (CFU) through the use of phenothiazine compound (methylene blue+ toluidine blue) as a photosensitizer, associated with red LED (λ640±5ηm) irradiation in orthodontic patients. Twenty-one patients consented to participate in the study. Three biofilm collections were performed around the brackets and gums of the inferior central incisors; first before any intervention (Control); second after 5min of pre-irradiation and the last one immediately after AmPDT. Subsequently, a microbiological routine for microorganism growth period were performed and CFU counting after a 24h done. The data showed that the AmPDT was able to reduce CFU count around 90% when compared to Control group (p=0.007) and also between the A-PDT and Photosensitizer groups (p=0.010). However, there were no differences between the Control and Photosensitizer groups. A-PDT associated with the use of phenothiazine compounds and red LED was able to significantly reduce the number of CFUs in orthodontic patients.

Efficacy of antimicrobial photodynamic therapy for elimination of Aggregatibacter actinomycetemcomitans biofilm on Laser-Lok titanium discs.

Antimicrobial Photodynamic therapy (aPDT) is a novel modality suggested for treatment of peri-implantitis. This study aimed to assess the effect of aPDT with toluidine blue (TBO) and indocyanine green (ICG) and 635 nm and 808 nm diode laser on Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) biofilm formed on Laser-Lok titanium discs. Eighty sterile Laser-Lok titanium discs were inoculated with A. actinomycetemcomitans to form biofilm and were randomly divided into 8 groups (n = 10) of control, chlorhexidine (CHX), TBO, ICG, 635 nm diode laser with 220 mW power, 808 nm diode laser with 250 mW power, 100 μg/mL TBO+635 nm diode laser and ICG+808 nm diode laser. Number of colony forming units (CFUs) on the surface of each disc was counted after the intervention. Data were analyzed using the Kruskal-Wallis test. Significant differences were noted in colony count among the eight groups after the intervention (P = 0.001). Pairwise comparisons with adjusted P value test showed that aPDT with TBO+635 nm laser and ICG+808 nm laser caused significant reduction of bacterial biofilm compared to the control group (P = 0.0001). TBO alone caused significant reduction of biofilm compared to the control group (P = 0.004). No other significant differences were noted (P > 0.05). Within the limitations of this study, the results showed that aPDT is a potential modality for decontamination of implant surface and reduction of A. actinomycetemcomitans biofilm in vitro. In this study, aPDT with TBO+635 nm diode laser and ICG+808 nm diode laser decreased the bacterial load on titanium discs.

Antimicrobial photodynamic therapy (aPDT) with curcumin and LED, as an enhancement to scaling and root planing in the treatment of residual pockets in diabetic patients: A randomized and controlled split-mouth clinical trial.

Residual pockets represent a risk factor for periodontal disease progression. Diabetes Mellitus (DM) may impair prognosis after cause-related therapy, mainly due to the chronic hyperglycemia that negatively influences tissue repair. This study evaluated the clinical efficacy of antimicrobial photodynamic therapy (aPDT) with curcumin (CUR) solution (100 mg/L) and LED irradiation (465-485 nm), as an adjunctive therapy to scaling and root planing (SRP), in the treatment of residual pockets in type 2 diabetic patients. Individuals with type 2 DM and chronic periodontitis presenting at least one residual pocket per quadrant were selected (n = 25). In each patient, all residual pockets with probing depth (PD) ≥5 mm and bleeding on probing (BOP) were allocated to receive, according to quadrant: 1) SRP (SRP group); 2) SRP and irrigation with CUR solution (100 mg/L) (CUR group); 3) SRP and LED irradiation (InGaN, 465-485 nm, 0.78 cm², 78 mW, 100 mW/cm², 60 s) (LED group); 4) SRP, irrigation with CUR solution (100 mg/L), one minute of pre-irradiation, and LED irradiation (InGaN, 465-485 nm, 60 s) (aPDT group). Clinical parameters of PD, gingival recession (GR), clinical attachment level (CAL), BOP and visible plaque index (PI) were evaluated at baseline, three and six months post-therapies. Differences between the examination periods in each group were analyzed by Friedman's test for non-parametric data, while parametric data were submitted to analysis of variance (One-way ANOVA), followed by Tukey's test. Intergroup comparisons were performed by Kruskal-Wallis test. In an intergroup comparison, the mean values for PD, GR, CAL, BOP and PI were not different at baseline, three and six months (p > 0.05). The intragroup comparison evidenced reduction in PD and BOP in all treatment groups at three and six months (p < 0.05). Significant CAL gain was notable only for the aPDT and LED groups at three months in comparison to baseline data (p < 0.05). Treatment of residual pockets in patients with type 2 DM through association of SRP with aPDT (CUR solution 100 mg/L and LED irradiation) or LED irradiation may yield short-term (three months) clinical benefits regarding CAL gain.

Assessment of sensitivity of selected Candida strains on antimicrobial photodynamic therapy using diode laser 635 nm and toluidine blue - In vitro research.

Photodynamic therapy is believed to be a promising treatment for Candida infections. This study evaluated the efficacy of antimicrobial photodynamic therapy (aPDT) using the 635 nm diode laser light and toluidine blue (TB) in the elimination of selected Candida species cultured on acrylic surface. 108 acrylic plates (Methyl Methacrylate Polymer, routinely used for the production of prosthetic dentures) were placed in three sterile Petri dishes and poured with prepared suspensions of Candida strains: C. albicans, C. glabrata, and C. krusei. After all procedures of fungi incubation, fungal biofilm was visible on the plates' surfaces. The acrylic plates were divided into nine study groups (B) and nine control groups (K) for further experiments. In the study groups, the acrylic plates with fungal biofilm were immersed in TB and afterwards laser irradiation was applicated with different exposure parameters (groups: B1 - 400 mW, 24 J/cm2, 30 s; B2 - 300 mW, 18 J/cm2, 30 s; B3 - 200 mW, 12 J/cm2, 30 s) separately for each Candida species. The control groups contained following parameters: no exposure to laser light or TB, treatment only with TB without laser irradiation, or only laser irradiation without previous immersion in TB. Calculations of colony forming units (CFUs) were conducted by using aCOlyte (Synbiosis). Differences in CFUs were analyzed by the Wilcoxon test. In all study groups, the reduction in CFUs was statistically significant. The differences in CFUs before and after intervention were insignificant. The K3 C.a. control group showed a statistical reduction of Candida albicans after laser irradiation. Our study confirmed the efficacy of aPDT against C. albicans, C. glabrata and C. krusei being dependent on the laser parameters and the type of fungus. The advantage of this study is the validation of aPDT effectiveness in in vitro studies to transpose this data into future clinical trials using photodynamic therapy in the treatment of oral candidiasis.

Effect of ultrasonic activation on the efficacy of antimicrobial photodynamic therapy: Evaluation of penetration depth of photosensitizer and elimination of Enterococcus faecalis biofilms.

This study aimed to assess the effect of ultrasonic activation of photosensitizer on the efficacy of Antimicrobial Photodynamic Therapy (aPDT) against Enterococcus faecalis and penetration depth of photosensitizer. In this ex vivo study, mature microbial biofilm of E. faecalis was formed in the root canals of 58 single-rooted single-canal mandibular incisors following their decoronation. The roots were longitudinally sectioned by a diamond disc and split into halves by a chisel. The E. faecalis biofilm was quantified and the penetration depth of photosensitizer was determined by the microbial viability assay and stereomicroscopic analysis in the following three study groups: (1) Ultrasonically activated 5.25% sodium hypochlorite (NaOCl) for 20 s, (2) aPDT using methylene blue (MB) plus 660 nm diode laser with 150 mW power for 1 minute, and (3) ultrasonically activated MB for 20 s followed by aPDT as in group 2. Independent sample t test and one way ANOVA were used to compare the dye penetration depth and microbial load, respectively in the apical and coronal regions among the groups. The penetration depth of photosensitizer in group 3 was significantly greater than that in group 2 (P < 0.05). The E. faecalis count in all three experimental groups was significantly lower than that in the control group (P < 0.05). Groups 1 and 3 were significantly superior to group 2 in terms of reduction in microbial count but the difference between groups 1 and 3 was not significant (P > 0.05). Ultrasonic activation of photosensitizer in aPDT increases the penetration depth of photosensitizer into the dentinal tubules and enhances its antibacterial activity. Ultrasonic activation of photosensitizer in aPDT enhances its penetration depth into dentinal tubules and increases antibacterial efficacy. There was no significant difference between antibacterial effects of aPDT + ultrasonic and ultrasonic activated NaOCl.

DNase increases the efficacy of antimicrobial photodynamic therapy on Candida albicans biofilms

Antimicrobial Photodynamic Therapy (aPDT) has been proposed as a means to treat Candida infections. However, microorganisms in biofilms are less susceptible to aPDT than planktonic cultures, possibly because the matrix limits the penetration of the photosensitizer. Therefore, the goals here were: (1) to target biofilm matrix components of a fluconazole-susceptible (S) and a fluconazole-resistant (R) C. albicans (Ca) strains using the hydrolytic enzymes β-glucanase and DNase individually or in combination; (2) to apply the best enzyme protocol in association with aPDT mediated by Photodithazine® (PDZ); (3) to verify under confocal microscope the penetration of PDZ in biofilms pre-treated or not with DNase at different periods of incubation. CaS and CaR 48h-old biofilms were incubated with the hydrolytic enzymes (5 min) and evaluated by cell viability, biomass, and matrix components. DNase showed the best outcomes by significantly reducing extracellular DNA (eDNA) and soluble proteins from the matrix of both strains; and water-soluble polysaccharides from CaR matrix. Subsequently, 48h-old biofilms were incubated with DNase for 5 min, followed by incubation with PDZ for 20 min and exposure to LED light (660 nm, 50 J/cm²). Controls were biofilms treated only with aPDT without DNase, PDZ only, PDZ + DNase, light only, light + DNase, and biofilm without treatment. Pre-treatment with DNase allowed PDZ penetration into deeper biofilm layers, and the aPDT effect was enhanced, showing a significant reduction of the cell viability (p = 0.000) and eDNA amounts (p ≤ 0.047). DNase affected the matrix composition improving the penetration of the photosensitizer, thereby, improving the effectiveness of subsequent aPDT.

Enhancing osteoblast functions on biofilm-contaminated titanium alloy by concentration-dependent use of methylene blue-mediated antimicrobial photodynamic therapy.

The concentration of methylene blue (MB) photosensitizer could affect the eradication efficacy of antimicrobial photodynamic therapy (aPDT) in the treatment of contaminated implants, which is linked to the osseointegration of the implant. We evaluated osteoblast functions on the contaminated SLA (sandblasting, large-grit and acid-etching) Ti alloy surfaces after the concentration-dependent use of MB-aPDT. Totally 1164 SLA discs were randomly distributed for the analyses of antibacterial efficacy and osteoblast functions. Gram-negative (Aggregatibacter actinomycetemcomitans; A. actinomycetemcomitans) or Gram-positive (Streptococcus mutans; S. mutans) adhered on disc samples was subjected to aPDT with different MB concentrations (200, 250, 300, 350, and 400 μg/mL) using 660 nm diode laser with maximum output 80 mW for 1 min irradiation (4.8 J/cm2). Bactericidal effect was examined by viability, morphology, and lipopolysaccharide (LPS) assays. The disinfected disc surfaces by MB-aPDT to support osteoblast-like MG63 attachment, proliferation, differentiation, and mineralization were assessed for the predetermined culture time intervals. The statistical differences between the means were performed using a one-way analysis of variance (ANOVA) with a post hoc Scheffe test. The results of the morphology observation and bacterial survival examination consistently indicated a remarkably lower quantity of bacterial colonies on biofilm-contaminated surfaces after the aPDT treatment with higher MB concentration. Similarly, the higher MB concentration in aPDT resulted in the lower LPS amounts remaining on the A. actinomycetemcomitans-contaminated surfaces. Intriguingly, the expression of osteoblast cultured on disinfected surfaces using aPDT with higher MB concentration was comparable to the control without contamination. Within the limits of this in vitro model, this formulation of 400 μg/mL MB used in aPDT may be not only the lethal concentration against the 2 bacteria-contaminated implants, but it could also enhance the osteoblast functions on the contaminated implants. Nevertheless, the efficacy in the clinical practice for peri-implantitis therapy remains to be studied.

Antimicrobial efficacy of photodynamic therapy using two different light sources on the titanium-adherent biofilms of Aggregatibacter actinomycetemcomitans: An in vitro study.

Antimicrobial photodynamic therapy (aPDT), is a promising approach proposed as an adjunct for the decontamination of dental implant surfaces. This study aimed to investigate the effect of aPDT with laser or light emitting diode (LED) compared with conventional chlorhexidine treatment on the titanium-attached biofilms of Aggregatibacter actinomycetemcomitans. Thirty-six acid-etched and sandblasted (SLA) titanium discs were allocated to six groups and incubated with the titanium-adherent biofilms of A. actinomycetemcomitans as follows. Negative control (no treatment applied), positive control (0.2% chlorhexidine solution), 0.1 mg/mL Toluidine Blue [TBO] group, aPDT-treated groups subjected either to diode laser with a wavelength of 635 nm wavelength or LED with the peak wavelength of 630 nm with TBO as photosensitizer and sterile control (not contaminated). Following sonication and transferring the specimens to the microplate, the number of colony-forming units (CFUs) per disc was calculated. Data were analyzed using one-way analysis of variance (ANOVA) and additional post hoc tests with the level of significance set at P < 0.05. aPDT using TBO + LED was significantly more effective (0.93 ± 0.24 × 104) in the suppression of A. actinomycetemcomitans compared with TBO + Laser (2.65 ± 0.7 × 104). However, the lowest mean of CFU count was found in sterile, and chlorhexidine groups, respectively (P < 0.0001) and the highest bacterial count was observed in the negative control group (P < 0.0001). LEDs and diode lasers have a lower ability to suppress A. actinomycetemcomitans biofilms compared to 0.2% chlorhexidine in vitro. However, the aPDT with the use of LED as a light source and TBO as a photosensitive agent could be an appropriate alternative to conventional chlorhexidine treatment.

Adjunctive antimicrobial photodynamic therapy to conventional chemo-mechanical debridement of infected root canal systems: A systematic review and meta-analysis

To investigate the efficacy of antimicrobial photodynamic therapy (aPDT) adjunctive to conventional chemo-mechanical debridement of root canal system in patients with endodontic infections. A meta-analysis was done according to the Cochrane Collaboration recommendations and PRISMA statement. Two independent reviewers performed an extensive literature search on electronic databases of MEDLINE, EMBASE, and SCOPUS up to January 2019. The search strategy was done from the following terms: antimicrobial photodynamic therapy OR photo-activated disinfection AND root canal therapy OR endodontic therapy OR root canal infection OR endodontic infection. The I2 test was used for determine the inter-study heterogeneity. Publication bias assessment carried out on the studies using the Egger's regression test. Sensitivity analysis of 10 randomized clinical trials (RCTs) revealed differences in microbial load reduction (0.143, 95% CI [0.06, 0.30], P = 0.000) in favor of aPDT plus conventional chemo-mechanical debridement. A high degree of heterogeneity (P = 0.000; Q- value = 154.74; I2 = 94.18%) was noticed among photosensitizer and light parameters. Subgroup analysis demonstrated the absence of heterogeneity in RCTs, with low risk of bias for microbial load reduction gain. No evidence of publication bias was determined. Although the aPDT parameters may vary from one RCT to the next, all studies found a reduction in microbial load with adjunctive use of aPDT; however, further high-quality RCTs focused on the standardized aPDT parameters are needed.