Nonsurgical antimicrobial photodynamic therapy in moderate vs severe peri-implant defects: a clinical pilot study

OBJECTIVE Recent review articles have shown that open debridement is more effective in the treatment of peri-implantitis than closed therapy. However, surgery may result in marginal recession and compromise esthetics. The purpose of this study was to assess the efficacy of nonsurgical antimicrobial photodynamic therapy (aPDT) in moderate vs severe defects. METHOD AND MATERIALS The study encompassed 16 patients with a total of 18 ailing implants. Ten of these implants showed moderate bone loss (< 5 mm; Group 1) and eight implants severe defects (5 through 8 mm; Group 2). All implants received aPDT without surgical intervention. At baseline and 2 weeks, 3 months, and 6 months after therapy, peri-implant health was assessed including sulcus bleeding index (SBI), probing depth (PD), distance from implant shoulder to marginal mucosa (DIM), and clinical attachment level (CAL). Radiographic evaluation of distance from implant to bone (DIB) allowed comparison of peri-implant hard tissues after 6 months. RESULTS Baseline values for SBI were comparable in both groups. Three months after therapy, in both groups, SBI and CAL decreased significantly. In contrast, after 6 months, CAL and DIB increased significantly in Group 2, not in Group 1. However, DIM-values were not statistically different 6 months after therapy in both groups. CONCLUSION Within the limits of this 6-month study, nonsurgical aPDT could stop bone resorption in moderate peri-implant defects but not in severe defects. However, marginal tissue recession was not significantly different in both groups at the end of the study. Therefore, especially in esthetically important sites, surgical treatment of severe peri-implantitis defects seems to remain mandatory.

Six-month results following treatment of aggressive periodontitis with antimicrobial photodynamic therapy or amoxicillin and metronidazole.

OBJECTIVE The use of antibacterial photodynamic therapy (aPDT) additionally to scaling and root planing (SRP) has been shown to positively influence the clinical outcomes. However, at present, it is unknown to what extent aPDT may represent a potential alternative to the use of systemic antibiotics in nonsurgical periodontal therapy in patients with aggressive periodontitis (AP). The aim of this study was to evaluate the outcomes following nonsurgical periodontal therapy and additional use of either aPDT or amoxicillin and metronidazole (AB) in patients with AP. MATERIAL AND METHODS Thirty-six patients with AP displaying at least three sites with pocket depth (PD) ≥6 mm were treated with SRP and either systemic administration of AB for 7 days or with two episodes of aPDT. The following clinical parameters were evaluated at baseline and at 6 months: plaque index (PI), bleeding on probing (BOP), PD, gingival recession (GR) and clinical attachment level (CAL). RESULTS Thirty-five patients have completed the 6-month evaluation. At 6 months, mean PD was statistically significantly reduced in both groups (from 5.0 ± 0.8 to 3.0 ± 0.6 mm with AB and from 5.1 ± 0.5 to 3.9 ± 0.8 mm with aPDT (p < 0.001)). AB yielded statistically significantly higher improvements in the primary outcome parameter PD (p < 0.001) when compared to aPDT. The number of pockets ≥7 mm was reduced from 141 to 3 after AB (p < 0.001) and from 137 to 45 after aPDT (p = 0.03). Both therapies resulted in statistically significant reductions in all parameters compared to baseline. CONCLUSION While both treatments resulted in statistically significant clinical improvements, AB showed statistically significantly higher PD reduction and lower number of pockets ≥7 mm compared to aPDT. CLINICAL RELEVANCE In patients with AP, the two times application of aPDT in conjunction with nonsurgical periodontal therapy cannot be considered an alternative to the systemic use of amoxicillin and metronidazole.

Reducing Vibrio load in Artemia nauplii usingantimicrobial photodynamic therapy: a promising strategy to reduce antibiotic application in shrimp larviculture

We propose antimicrobial photodynamic therapy (aPDT) as an alternative strategy to reduce the use of antibiotics in shrimp larviculture systems. The growth of a multiple antibiotic resistant Vibrio harveyi strain was effectively controlled by treating the cells with Rose Bengal and photosensitizing for 30 min using a halogen lamp. This resulted in the death of > 50% of the cells within the first 10 min of exposure and the 50% reduction in the cell wall integrity after 30 min could be attributed to the destruction of outer membrane protein of V. harveyi by reactive oxygen intermediates produced during the photosensitization. Further, mesocosm experiments with V. harveyi and Artemia nauplii demonstrated that in 30 min, the aPDT could kill 78.9% and 91.2% of heterotrophic bacterial and Vibrio population respectively. In conclusion, the study demonstrated that aPDT with its rapid action and as yet unreported resistance development possibilities could be a propitious strategy to reduce the use of antibiotics in shrimp larviculture systems and thereby, avoid their hazardous effects on human health and the ecosystem at large.

Adjunctive antimicrobial photodynamic treatment of experimentally induced periodontitis in rats with ovariectomy

Background: The aim of this study is to compare antimicrobial photodynamic therapy (aPDT) as an adjunctive therapy to scaling and root planing (SRP) for the treatment of experimentally induced periodontitis in rats with ovariectomy (OVX) that are or are not treated with estrogen replacement. Methods: A total of 270 female rats were divided into three groups: 1) normal rats; 2) rats with OVX; and 3) rats with OVX with estrogen replacement. Periodontal disease was induced through the introduction of a cotton thread around the mandibular left first molar. After 7 days, the ligature was removed, and the rats were randomly divided into the following treatment groups: 1) SRP plus saline solution; 2) SRP plus low-level laser therapy (LLLT); and 3) SRP plus toluidine blue O irrigation followed by LLLT. Ten rats from each group were euthanized at days 7, 15, and 30 after dental treatment. Bone loss (BL) in the furcation region was evaluated using histometric and immunohistochemical analyses. Results: aPDT treatment resulted in reduced BL compared with SRP treatment at all time points. Additionally, rats treated with aPDT exhibited reduced numbers of tartrate-resistant acid-phosphatase-positive cells and more proliferating cell nuclear antigen-positive cells in all treatment groups regardless of estrogen status. Whereas rats treated with aPDT showed weak immunoreactivity to the receptor activator of nuclear factor-k B ligand at day 7 post-treatment, strong osteoprotegerin immunoreactivity was observed at day 15 post-treatment. Conclusion: aPDT is an effective adjunctive therapy for the treatment of periodontitis in rats with OVX that are or are not given estrogen replacement therapy.

Susceptibility of multispecies biofilm to photodynamic therapy using Photodithazine®

This in vitro study evaluated the effect of photodynamic therapy (PDT) on the multispecies biofilm of Candida albicans, Candida glabrata, and Streptococcus mutans. Standardized fungal and bacterial suspensions were cultivated appropriately for each species and inoculated in 96-well microtiter plates for mix-biofilm formation. After 48 h of incubation, the biofilms were submitted to PDT (P + L+) using Photodithazine® (PDZ) at 100, 150, 175, 200, or 250 mg/mL for 20 min and 37.5 J/cm2 of light-emitting diode (LED) (660 nm). Additional samples were treated only with PDZ (P + L-) or LED (P-L+), or neither (control, P-L-). Afterwards, the biofilms were evaluated by quantification of colonies (CFU/mL), metabolic activity (XTT reduction assay), total biomass (crystal violet staining), and confocal scanning laser microscopy (CSLM). Data were analyzed by one-way ANOVA and Tukey tests (p < 0.05). Compared with the control, PDT promoted a significant reduction in colonies viability of the three species evaluated with 175 and 200 mg/mL of PDZ. PDT also significantly reduced the metabolic activity of the biofilms compared with the control, despite the PDZ concentration. However, no significant difference was found in the total biomass of samples submitted or not to PDT. For all analysis, no significant difference was verified among P-L-, P + L-, and P-L+. CSLM showed a visual increase of dead cells after PDT. PDT-mediated PDZ was effective in reducing the cell viability of multispecies biofilm. © 2013 Springer-Verlag London.

The influence of photodynamic therapy parameters on the inactivation of Candida spp: in vitro and in vivo studies

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of Photodynamic Therapy with Blue Light and Curcumin as Mouth Rinse for Oral Disinfection: A Randomized Controlled Trial

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Is Photodynamic Therapy an Effective Treatment for Periodontal and Peri-Implant Infections?

Antimicrobial photodynamic therapy (PDT) has attracted much attention for the treatment of pathogenic biofilm associated with peridontitis and peri-implantitis. However, data from randomized controlled clinical studies (RCTs) are limited and, to some extent, controversial, making it difficult to provide appropriate recommendations. Therefore, the aims of the present study were (a) to provide an overview on the current evidence from RCTs evaluating the potential clinical benefit for the additional use of PDT to subgingival mechanical debridement (ie, scaling and root planing) alone in nonsurgical periodontal therapy; and (b) to provide clinical recommendations for the use of PDT in periodontal practice.

Evaluation Of Photodynamic Therapy Using A Diode Laser And Different Photosensitizers Against Enterococcus Faecalis.

Photodynamic therapy (PDT) has been proven to be effective in disinfecting root canals. The aim of this present study was to evaluate the effects of PDT on the viability of Enterococcus faecalis using methylene blue (MB) and malachite green (MG) as photosensitizers. Solutions containing E. faecalis (ATCC 29212) were prepared and harvested by centrifugation to obtain cell suspensions, which were mixed with MB and MG. Samples were individually irradiated by the diode laser at a distance of 1mm for 30, 60, or 120 seconds. Colonyforming units (CFU) were determined for each treatment. PDT for 60 and 120 seconds with MG reduced E. faecalis viability significantly. Similar results were obtained when MB was used as photosensitizer. PDT using MB and MG have antibacterial effect against E. faecalis, showing potential to be used as an adjunctive antimicrobial procedure in endodontic therapy.

Antimicrobial photodynamic action on dentin using a light-emitting diode light source

Objective: The aim of this study was the evaluation of two different photosensitizers activated by red light emitted by light-emitting diodes (LEDs) in the decontamination of carious bovine dentin. Materials and Methods: Fifteen bovine incisors were used to obtain dentin samples which were immersed in brain-heart infusion culture medium supplemented with 1% glucose, 2% sucrose, and 1% young primary culture of Lactobacillus acidophilus 108 CFU/mL and Streptococcus mutans 108 CFU/mL for caries induction. Three different concentrations of the Photogem solution, a hematoporphyrin derivative (1, 2, and 3 mg/mL) and two different concentrations of toluidine blue O (TBO), a basic dye (0.025 and 0.1 mg/mL) were used. To activate the photosensitizers two different light exposure times were used: 60 sec and 120 sec, corresponding respectively to the doses of 24 J/cm(2) and 48 J/cm(2). Results: After counting the numbers of CFU per milligram of carious dentin, we observed that the use of LED energy in association with Photogem or TBO was effective for bacterial reduction in carious dentin, and that the greatest effect on S. mutans and L. acidophilus was obtained with TBO at 0.1 mg/mL and a dose of 48 J/cm(2). It was also observed that the overall toxicity of TBO was higher than that of Photogem, and that the phototoxicity of TBO was higher than that of Photogem. Conclusion: Based on our data we propose a mathematical model for the photodynamic effect when different photosensitizer concentrations and light doses are used.

Fungicidal effect of photodynamic therapy against fluconazole-resistant Candida albicans and Candida glabrata

P>Although photodynamic therapy (PDT) has shown great promise for the inactivation of Candida species, its effectiveness against azole-resistant pathogens remains poorly documented. This in vitro study describes the association of Photogem (R) (Photogem, Moscow, Russia) with LED (light emitting diode) light for the photoinactivation of fluconazole-resistant (FR) and American Type Culture Collection (ATCC) strains of Candida albicans and Candida glabrata. Suspensions of each Candida strain were treated with five Photogem (R) concentrations and exposed to four LED light fluences (14, 24, 34 or 50 min of illumination). After incubation (48 h at 37 degrees C), colonies were counted (CFU ml-1). Single-species biofilms were generated on cellulose membrane filters, treated with 25.0 mg l-1 of Photogem (R) and illuminated at 37.5 J cm-2. The biofilms were then disrupted and the viable yeast cells present were determined. Planktonic suspensions of FR strains were effectively killed after PDT. It was observed that the fungicidal effect of PDT was strain-dependent. Significant decreases in biofilm viability were observed for three strains of C. albicans and for two strains of C. glabrata. The results of this investigation demonstrated that although PDT was effective against Candida species, fluconazole-resistant strains showed reduced sensitivity to PDT. Moreover, single-species biofilms were less susceptible to PDT than their planktonic counterparts.