The biological effects of different LED wavelengths in the health field. A review / Os efeitos biológicos de diferentes comprimentos de onda de LED na área da saúde. Uma revisão

Introduction: the use of light emitting diodes (LED) in domestic and public vias have increased in the last 20 years. In addition, the LED light has been used as a light source for medical applications. Objective: since humans are increasingly exposed to LEDs, there is an urgency to investigate the possible biological effects on tissues caused by this exposure. So, researchers have been focused their investigations in the application of this light in the health field. Material and method: in this review, a search in important databases was performed on the biological effects caused after application of different LED light protocols in in vitro and in vivo studies. Result: although most published papers have shown positive results, some of them reported negative biological effects of light LEDs technology on humans' cells/tissues. Conclusion: therefore, the comprehension of the biological effects caused by light LEDs will provide a better assessment of the risks involved using this technology.

Introdução: o uso de diodos emissores de luz ("LED") em vias domésticas e públicas tem aumentado nos últimos 20 anos. Além disso, a luz LED tem sido usada para aplicações médicas. Objetivo: pelo fato de seres humanos estarem cada vez mais expostos aos LEDs, há urgência em investigar os possíveis efeitos biológicos nos tecidos causados por esta exposição. Assim, pesquisadores têm focado suas investigações no uso desta luz na área da saúde. Material e método: nesta revisão foi realizada uma pesquisa em bancos de dados conceituados sobre os efeitos biológicos causados após aplicação de diferentes protocolos de luz LED em estudos in vitro e in vivo. Resultado: embora a maioria dos artigos publicados tenham mostrado resultados positivos, alguns deles relataram efeitos biológicos negativos da tecnologia de LEDs nas células/tecidos humanos. Conclusão: portanto, a compreensão dos efeitos biológicos causados pela luz LED proporcionará uma melhor avaliação dos riscos envolvidos no uso desta tecnologia.

Gene expression of Candida albicans strains isolates from patients with denture stomatitis submitted to treatments with photodynamic therapy and nystatin.

The study evaluated the effect of antimicrobial photodynamic therapy (aPDT) and nystatin (NYS) in the expression of genes (ACT1, ALS1, CAP1, CAT1, EFG1, HWP1, LIP3, PLB1, SAP1, and SOD1) involved in the virulence of Candida albicans strains recovered from patients with denture stomatitis (DS). These strains were isolated from the patients before (initial) and after treatment (final), and 45 days after the treatments (follow-up). For gene expression analyses, RNA was isolated from the clinical strains, followed by cDNA synthesis and qPCR using specific primers for each target gene. The samples that present integrity were pooled to increase the RNA yield. In the end, four patients treated with aPDT and five patients treated with NYS had the clinical isolates of C. albicans submitted to gene expression evaluation. The data demonstrated a statistical difference in the expression of PLB1 and ACT1 for the different therapies (aPDT versus NYS). Also, there was a statistical difference in the expression of CAT1, SOD1, and LIP3 at the time intervals assessed (initial, final, and follow-up). In contrast, no statistical difference was found in the expression of ALS1, HWP1, EFG1, CAP1, CAT1, SOD1, LIP3, and SAP1 between the therapies, while no significant difference was detected at the time intervals evaluated for ALS1, HWP1, EFG1, CAP1, and SAP1. Therefore, the topical treatments for DS with aPDT or NYS did not effect the expression of most C. albicans virulence genes evaluated.

Consecutive treatments with photodynamic therapy and nystatin altered the expression of virulence and ergosterol biosynthesis genes of a fluconazole-resistant Candida albicans in vivo.

This investigation assessed the effect of five consecutive daily topical treatments of antimicrobial photodynamic therapy (aPDT), nystatin (NYS), and an association of treatments on a fluconazole-resistant strain of Candida albicans colonizing the tongues of mice. After the last treatments application, colonies of C. albicans were recovered from the tongues and used to determine their fluconazole susceptibility. After 24 hours of the last treatment, the mice tongues were processed to evaluate the expression of C. albicans genes related to the virulence and ergosterol production. The fluconazole susceptibility test yielded a resistance profile similar for all treatment groups and the control group (no treatment). The treatments aPDT, NYS, NYS+aPDT, and aPDT+NYS promoted a reduction in ALS1, EFG1, CAP1, SOD1, SAP1, and LIP3 expression. The expression of HWP1 was higher in the three groups containing nystatin. In contrast, the treatments produced a significative increase in CAT1 gene expression, mainly in the groups in which aPDT was performed. The expression of genes related to ergosterol production was significantly reduced by the treatments evaluated (aPDT, NYS, NYS+aPDT, and aPDT+NYS). Thus, the consecutive topical treatments performed on mice tongues promoted a reduction in the expression of virulence and ergosterol biosynthesis genes of a fluconazole-resistant C. albicans.

A randomized clinical trial evaluating Photodithazine-mediated Antimicrobial Photodynamic Therapy as a treatment for Denture stomatitis.

OBJECTIVE: This randomized clinical trial assessed antimicrobial Photodynamic Therapy (aPDT) mediated by Photodithazine (PDZ) to treat patients with denture stomatitis (DS). METHODOLOGIES: Patients with DS were randomly assigned to the groups: aPDT (n = 30) and nystatin (NYS, n = 35). aPDT patients received 6 aPDT sessions, three times a week for 15 days, which involved PDZ (200 mg/L) topical application (20 min) on the palate and upper denture, followed by LED illumination (660 nm, 50 J/cm²). NYS patients were instructed to rinse one dropper of this medication for one minute, four times a day, for 15 days. Microbiological collections of dentures and palates were performed and cultured on blood agar and CHROMAgar Candida. Microbial viability was determined, and photographs of the palates were taken for clinical evaluation. Data were analyzed by Repeated Measure Linear Model and Bonferroni (p ≤ 0.05). RESULTS: aPDT was more effective to reduce the total microbiota than NYS. At the end of the treatments, aPDT reduced 1.98 from the palate and 1.91 log10 from the denture, while NYS reduced 0.05 and 0.17 log10, respectively. Moreover, aPDT was as effective as NYS to reduce Candida. Reductions of 0.68 and 0.77 log10 were observed in the palate and denture of aPDT group, while reductions of 0.57 and 1.43 log10 were achieved in the NYS group, respectively. Regarding to oral lesion, 53.3 and 54.2 % of the patients from aPDT and NYS groups had clinical improvement. However, the recurrence of DS was observed in both groups. CONCLUSION: PDZ-mediated aPDT is a promising treatment for DS.

Successive applications of Antimicrobial Photodynamic Therapy effects the susceptibility of Candida albicans grown in medium with or without fluconazole.

Antimicrobial Photodynamic Therapy (aPDT) was introduced as a therapy due to resistance that microorganisms have developed to conventional drugs. The study aimed to evaluate the potential of successive applications of aPDT in effecting Candida albicans susceptibility and also whether the presence of fluconazole effected the recovery of the fungi in the culture medium. Planktonic cultures and biofilm were subjected to successive applications of Photodithazine-mediated (25 mg/L) LED-associated aPDT (660 nm, 34 mW/cm2). Plating was performed on Sabouraud Dextrose Agar supplemented or not with fluconazole to recover colony-forming units per milliliter (CFU/mL). Surviving cells were recovered, recultivated, and again exposed to the treatment. The treatments were performed until not enough colonies were available for recultivation and continuation of the protocol. The complete inactivation of the fungus was obtained after three and five applications for planktonic culture and biofilm, respectively. A reduction of 6.3 log10 was observed after third applications in the planktonic cultures grown on medium without fluconazole, while there was a 7 log10 reduction of these cultures grown on fluconazole medium. However, a reduction of 6.1 log10 occurred for biofilms after fifth applications for cultures grown on medium without fluconazole, while a reduction of 6.7 log10 was observed for cultures grown on medium with the antifungal. Thus, aPDT was potentiated by fluconazole. C. albicans in planktonic and biofilm cultures are susceptible to successive applications of PDZ-mediated aPDT, and tolerance to aPDT is higher in the biofilm.

Antimicrobial photodynamic therapy reduces gene expression of Candida albicans in biofilms.

The present study evaluated whether the oxidative stress caused by antimicrobial photodynamic therapy (aPDT) affects the expression of C. albicans genes related to adhesion and biofilm formation (ALS1 and HPW1) and oxidative stress response (CAP1, CAT1, and SOD1). The aPDT was mediated by two photosensitizing agents (PSs) Photodithazine® (PDZ at 100 and 200 mg/L) or Curcumin (CUR at 40 and 80 µM) and LED (37.5 J/cm2 or 50 J/cm2). The quantification of the expression was performed by Reverse Transcription-Quantitative Polymerase Chain Reaction (RT-qPCR) using specific primers for the target genes. The data were analyzed by Analysis of Variance (α = 0.05), followed by Tukey's post-test. It was observed reduction in the expression of ALS1, HWP1, CAP1, CAT1, and SOD1 when aPDT was performed using 200 mg/L PDZ and 80 µM CUR associated to LED (37.7 and 50 J/cm2, respectively) and using 100 mg/L PDZ and 40 µM CUR with LED of 50 J/cm2 (versus control). Also, the expression of CAP1 and SOD1 genes was reduced after aPDT using 100 mg/L PDZ and LED of 37.5 J/cm2. There was a significant reduction in the expression of genes HWP1, CAP1, and SOD1 after aPDT using 40 µM CUR and 37.5 J/cm2 (versus the control group). The application of LED only at 37.5 and 50 J/cm2 promoted down-regulation of ALS1, CAP1, CAT1, and SOD1 genes (versus the control group). Therefore, aPDT mediated by LED -associated PSs PDZ and CUR promoted a reduction in the expression of the five C. albicans genes evaluated.

Antimicrobial Photodynamic Therapy in Combination with Nystatin in the Treatment of Experimental Oral Candidiasis Induced by Candida albicans Resistant to Fluconazole.

BACKGROUND: It has been demonstrated that azole-resistant strains of Candida albicans have a greater resistance to antimicrobial photodynamic therapy (aPDT) when compared to their more susceptible counterparts. For this reason, the present study evaluated the efficacy of aPDT, together with nystatin (NYS), in the treatment of oral candidiasis in vivo. METHODS: Mice were infected with fluconazole-resistant C. albicans (ATCC 96901). To perform the combined therapy, aPDT, mediated by Photodithazine (PDZ) and LED light, was used together with NYS. The efficacy of the treatments was evaluated by microbiological, macroscopic, histopathological and Confocal Scanning Laser Microscopy analyses of the lesions. The expression of p21 and p53, proteins associated with cell death, from the tongues of mice, was also performed. RESULTS: The combined therapy reduced the fungal viability by around 2.6 log10 and decreased the oral lesions and the inflammatory reaction. Additionally, it stimulated the production of p53 and p21. CONCLUSIONS: The combined therapy is a promising alternative treatment for oral candidiasis induced by C. albicans resistant to fluconazole.

Antimicrobial photodynamic therapy reduces adhesion capacity and biofilm formation of Candida albicans from induced oral candidiasis in mice.

BACKGROUND: Antimicrobial photodynamic therapy (aPDT) has been considered an alternative therapeutic modality for the treatment of Candida infections. However, most studies are focused mainly on microorganism's inactivation efficiency. Here, we evaluated the efficacy of aPDT mediated by chloro-aluminum phthalocyanine encapsulated in cationic nanoemulsions (ClAlP-NE) to treat oral candidiasis in vivo and its effect on the adhesion and biofilm formation of Candida albicans. METHODS: For this, mice were immunosuppressed and inoculated with C. albicans to produce oral candidiasis. aPDT and Nystatin were applied for 5 successive sessions. Next, the microbiological evaluation was determined (CFU/ml) and the analyses of virulence factors (adhesion capacity and biofilm formation) were performed. Data were analyzed by Two-way ANOVA (α = 0.05). RESULTS: aPDT was as effective as Nystatin reducing 1.4 and 2.0 log10 of the cell viability (p ≤ 0.0001), respectively. Both treatments reduced the adhesion capacity and biofilm formation of C. albicans (p ≤ 0.0001) CONCLUSION: : ClAlP-NE-mediated aPDT was effective in reducing the virulence factors of C. albicans and also to treat induced oral candidiasis in mice.

Photodithazine-mediated antimicrobial photodynamic therapy against fluconazole-resistant Candida albicans in vivo.

This study evaluated the efficacy of antimicrobial Photodynamic Therapy (aPDT) against fluconazole-resistant Candida albicans in a murine model of oral candidosis. Mice were inoculated with two clinical isolates (R10, R15) and one reference strain (ATCC) of resistant C. albicans to produce oral candidosis. After inoculation, aPDT mediated by Photodithazine® (PDZ) and LED light was performed. The use of PDZ or light only was also investigated. Additional animals were treated with Nystatin (NYS). Untreated or healthy mice were also evaluated. Microbiological evaluation was performed by recovering C. albicans from the tongue via colony-forming units. Animals were killed 24 hours after treatments, and the tongues were removed for histological analysis. Data were analyzed by one-way ANOVA and Tukey test (P < .05). The results demonstrated that all strains showed the same behavior after aPDT and NYS treatment. A significant reduction in C. albicans viability was achieved after both treatments for R15 and ATCC. No significant reduction was verified for C. albicans R10 submitted to aPDT or NYS. The histological analysis revealed that aPDT did not cause side effects on tissues. aPDT was effective for inactivation of two fluconazole-resistant C. albicans of the three strains evaluated.

Antimicrobial Photodynamic Therapy Mediated by Curcumin-Loaded Polymeric Nanoparticles in a Murine Model of Oral Candidiasis.

Antimicrobial photodynamic therapy (aPDT) has been proposed as an alternative method for oral candidiasis (OC), while nanocarriers have been used to improve the water solubility of curcumin (CUR). The aim of this study is to encapsulate CUR in polymeric nanoparticles (NPs) and to evaluate its photodynamic effects on a murine model of OC. Anionic and cationic CUR-NP is synthesized using poly-lactic acid and dextran sulfate and then characterized. Female mice are immunosuppressed and inoculated with Candida albicans (Ca) to induce OC. aPDT is performed by applying CUR-NP or free CUR on the dorsum of the tongue, followed by blue light irradiation for five consecutive days. Nystatin is used as positive control. Afterward, Ca are recovered and cultivated. Animals are euthanized for histological, immunohistochemical, and DNA damage evaluation. Encapsulation in NP improves the water solubility of CUR. Nystatin shows the highest reduction of Ca, followed by aPDT mediated by free CUR, which results in immunolabelling of cytokeratins closer to those observed for healthy animals. Anionic CUR-NP does not show antifungal effect, and cationic CUR-NP reduces Ca even in the absence of light. DNA damage is associated with Ca infection. Consecutive aPDT application is a safe treatment for OC.

Antimicrobial Photodynamic Therapy mediated by Photodithazine® in the treatment of denture stomatitis: A case report.

Antimicrobial Photodynamic Therapy (aPDT) mediated by Photodithazine® (PDZ) has shown efficacy in the inactivation of Candida spp. in in vitro and in vivo studies. This preliminary study reports five clinical cases of patients with denture stomatitis (DS) treated with PDZ-mediated aPDT. Five individuals diagnosed with DS were selected and submitted to aPDT 3 times a week for 15 days (6 sessions). In each session, 200 mg/L of PDZ gel was applied on the upper prostheses and on the palate of the patients for 20 min, then, illuminated by a light emitting diode at 660 nm (50 J/cm2). Microbiological samples from prostheses and palates were also performed and cultured on Sabouraud Dextrose Agar and Blood Agar. The values ​​of colony forming units per milliliter (CFU/mL) were determined. Standardized photographs of the palates were taken prior the treatment (initial), at the end (final) and until 45 days after the completion of treatments. The results demonstrated that the aPDT treatment reduced Candida spp. and the total microbiota viability ​​at the end of the treatment. For most patients, the CFU/mL values obtained in the last microbiological collection (day 45) were lower than those found before the treatment (initial). Three patients presented clinical resolution of DS (no DS signal) after aPDT treatment. One individual demonstrated reduction in palatal inflammation and another one did not show improvement in the oral lesion. Recurrence of DS was observed in all individuals in the follow-up period. PDZ-mediated aPDT may be a promising treatment for DS.

Photoinactivation of single and mixed biofilms of Candida albicans and non-albicans Candida species using Photodythazine® [corrected].

This study evaluated the effectiveness of antimicrobial photodynamic therapy (aPDT) mediated by Photodithazine® (PDZ) formulated in hydrogel, in the inactivation of mono and duo-species biofilms of Candida albicans, Candida glabrata and Candida tropicalis. Standardized suspensions of each strain were prepared and after biofilm formation, mono-species were treated with 150 and 175mg/L of PDZ for 20min (pre-irradiation time), and exposed to LED light at a dose of 37.5J/cm2 (660nm). The duo-species biofilms (C. albicans+C. glabrata and C. albicans+C. tropicalis) were treated with 150mg/L of PDZ and light. Additional samples were treated with PDZ or light only, and the control did not receive any treatment. Next, microbiological evaluation was performed by spreading the cells on Sabouraud Dextrose Agar and CHROMagar Candida for colony forming units (CFU/mL). Moreover, the total biomass of biofilm was verified using the crystal violet staining assay (CV). The data were submitted to ANOVA and Tukey post-hoc (α=0.05). The use of PDZ 150mg/L promoted a reduction of 1.0, 1.2, 1.5 log10 in the viability of C. glabrata, C. albicans and C. tropicalis, respectively. The same concentration reduced in 1.0 log10 the viability of each species grown as duo-species biofilms. The crystal violet assay showed that the use of 150mg/L reduced 24.4%, 39.2% and 43.7% of the total biomass of C. albicans, C. tropicalis and C. glabrata, respectively. aPDT did not reduce the total biomass to the duo-species biofilms. Thus, PDZ-mediated aPDT was more effective in the inactivation of mono-species biofilms of Candida spp. compared with duo-species biofilm.

Treatment of Oral Candidiasis Using Photodithazine®- Mediated Photodynamic Therapy In Vivo.

This study evaluated the effectiveness of antimicrobial photodynamic therapy (aPDT) in the treatment of oral candidiasis in a murine model using Photodithazine® (PDZ). This model of oral candidiasis was developed to allow the monitoring of the infection and the establishment of the aPDT treatment. Six-week-old female mice were immunosuppressed and inoculated with C. albicans to induce oral candidiasis. PDZ-mediated aPDT and nystatin treatment were carried out for 5 consecutive days with one application per day. The macroscopic evaluation of oral lesions was performed. After each treatment, the tongue was swabbed to recover C. albicans cells. Viable colonies were quantified and the number of CFU/ml determined. The animals were sacrificed 24 hours and 7 days after treatment and the tongues were surgically removed for histological analysis and analysis of inflammatory cytokines expression (IL-1, TNF-α and IL-6) by RT-qPCR. Data were analyzed by two-way ANOVA. PDZ-mediated aPDT was as effective as Nystatin (NYS group) in the inactivation of C. albicans, reducing 3 and 3.2 logs10 respectively, 24 h after treatment (p<0.05). Animals underwent PDZ-mediated aPDT showed complete remission of oral lesions, while animals treated with NYS presented partial remission of oral lesions in both periods assessed. Histological evaluation revealed mild inflammatory infiltrate in the groups treated with aPDT and NYS in both periods assessed. The aPDT induced the TNF-α expression when compared with the control (P-L-) (p<0.05), 24 h and 7 days after treatment. In summary, the murine model developed here was able to mimic the infection and PDZ-mediated aPDT was effective to treat mice with oral candidiasis.

Genotoxic effect of photodynamic therapy mediated by curcumin on Candida albicans.

Photodynamic therapy (PDT) is a promising method for localized and specific inactivation of fungi and bacteria. A nontoxic light-sensitive compound is taken up by cells, which are then exposed selectively to light, which activates toxicity of the compound. We investigated the potential of sublethal PDT using light-sensitive curcumin (CUR) in combination with blue (455 nm) light to promote reactive oxygen species (ROS) formation in the form of singlet oxygen and DNA damage of Candida albicans. Surprisingly, CUR-mediated PDT but also light alone caused significantly longer comet tails, an indication of DNA damage of C. albicans when compared with the negative control. The intracellular ROS production was also significantly higher for the group treated only with light. However, PDT compared to blue light alone significantly slowed DNA repair. Comet tails decreased during 30 min visualized as a 90% reduction in length in the absence of light for cells treated with light alone, while comet tails of cells treated with PDT only diminished in size about 45%. These results indicate that complex mechanisms may result in PDT in a way that should be considered when choosing the photosensitive compound and other aspects of the treatment design.

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/cm(2) 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.

Curcumin-mediated photodynamic inactivation of Candida albicans in a murine model of oral candidiasis.

In vitro investigations of curcumin-mediated photodynamic therapy (PDT) are encouraging, but there is a lack of reliable in vivo evidence of its efficacy. This study describes the photoinactivation of Candida albicans in a murine model of oral candidiasis, using curcumin as a photosensitizer. Forty immunosuppressed mice were orally inoculated with C. albicans and after five days, they received topical curcumin (20, 40 and 80 µM) and illumination with LED light. The use of curcumin or light alone were also investigated. Positive control animals did not receive any treatment and negative control animals were not inoculated with C. albicans. The number of surviving yeast cells was determined and analyzed by ANOVA and Tukey's post-hoc test (α = 0.05). Histological evaluation of the presence of yeast and inflammatory reaction was also conducted. All exposures to curcumin with LED light caused a significant reduction in C. albicans viability after PDT, but the use of 80 µM curcumin associated with light was able to induce the highest log10 reduction in colony counts (4 logs). It was concluded that curcumin-mediated PDT proved to be effective for in vivo inactivation of C. albicans without harming the host tissue of mice.

Diametral tensile strength and film thickness of an experimental dental luting agent derived from castor oil.

UNLABELLED: The need to develop new dental luting agents in order to improve the success of treatments has greatly motivated research. OBJECTIVE: The aim of this study was to evaluate the diametral tensile strength (DTS) and film thickness (FT) of an experimental dental luting agent derived from castor oil (COP) with or without addition of different quantities of filler (calcium carbonate - CaCO3). MATERIAL AND METHODS: Eighty specimens were manufactured (DTS N=40; FT N=40) and divided into 4 groups: Pure COP; COP 10%; COP 50% and zinc phosphate (control). The cements were mixed according to the manufacturers' recommendations and submitted to the tests. The DTS test was performed in the MTS 810 testing machine (10 KN, 0.5 mm/min). For FT test, the cements were sandwiched between two glass plates (2 cm²) and a load of 15 kg was applied vertically on the top of the specimen for 10 min. The data were analyzed by means of one-way ANOVA and Tukey's test (α=0.05). RESULTS: The values of DTS (MPa) were: Pure COP- 10.94 ± 1.30; COP 10%- 30.06 ± 0.64; COP 50%- 29.87 ± 0.27; zinc phosphate- 4.88 ± 0.96. The values of FT (µm) were: Pure COP- 31.09 ± 3.16; COP 10%- 17.05 ± 4.83; COP 50%- 13.03 ± 4.83; Zinc Phosphate- 20.00 ± 0.12. One-way ANOVA showed statistically significant differences among the groups (DTS - p=1.01E-40; FT - p=2.4E-10). CONCLUSION: The experimental dental luting agent with 50% of filler showed the best diametral tensile strength and film thickness.

Diametral tensile strength and film thickness of an experimental dental luting agent derived from castor oil

The need to develop new dental luting agents in order to improve the success of treatments has greatly motivated research. OBJECTIVE: The aim of this study was to evaluate the diametral tensile strength (DTS) and film thickness (FT) of an experimental dental luting agent derived from castor oil (COP) with or without addition of different quantities of filler (calcium carbonate - CaCO3). MATERIAL AND METHODS: Eighty specimens were manufactured (DTS N=40; FT N=40) and divided into 4 groups: Pure COP; COP 10 percent; COP 50 percent and zinc phosphate (control). The cements were mixed according to the manufacturers' recommendations and submitted to the tests. The DTS test was performed in the MTS 810 testing machine (10 KN, 0.5 mm/min). For FT test, the cements were sandwiched between two glass plates (2 cm²) and a load of 15 kg was applied vertically on the top of the specimen for 10 min. The data were analyzed by means of one-way ANOVA and Tukey's test (α=0.05). RESULTS: The values of DTS (MPa) were: Pure COP- 10.94±1.30; COP 10 percent- 30.06±0.64; COP 50 percent- 29.87±0.27; zinc phosphate- 4.88±0.96. The values of FT (µm) were: Pure COP- 31.09±3.16; COP 10 percent- 17.05±4.83; COP 50 percent- 13.03±4.83; Zinc Phosphate- 20.00±0.12. One-way ANOVA showed statistically significant differences among the groups (DTS - p=1.01E-40; FT - p=2.4E-10). CONCLUSION: The experimental dental luting agent with 50 percent of filler showed the best diametral tensile strength and film thickness.

Efetividade da terapia fotodinâmica mediada pelo fotossensibilizador Photodithazine® na inativação de Candida albicans in vivo / Efectiveness of photodynamic therapy mediated by Photodithazine ® for C. albicans inactivation in vivo

Este trabalho teve por objetivo avaliar a efetividade da terapia fotodinâmica (PDT) mediada pelo fotossensibilizador (FS) Photodithazine® (PDZ), associado à luz do tipo LED (660nm). Para tanto, foram utilizados 55 camundongos com aproximadamente 6 semanas de vida, os quais foram submetidos a indução de candidose no dorso da língua. Inicialmente os animais foram imunossuprimidos e no dia seguinte se realizou a inoculação de C. albicans na língua dos mesmos por meio de swabs embebidos na suspensão (107 Ufc/mL). Para a realização da terapia fotodinâmica o FS foi avaliado nas concentrações de 75, 100, 125 e 150mg/L. Tais grupos experimentais foram denominados de (P+L+ 75mg/L, P+L+ 100mg/L, P+L+ 125mg/L, P+L+ 150mg/L) associados a uma dose de luz de 37,5 J/cm2 . Para a verificação apenas do efeito da PDZ, a mesma foi aplicada na língua dos animais, sem iluminação (grupos denominados de P+L- 75mg/L, P+L- 100mg/L, P+L- 125mg/L, P+L- 150mg/L). O efeito da luz foi avaliado por meio da iluminação das línguas com dose de luz de 37,5J/cm2 , (grupo denominado de P-L+ 37,5J/cm2 ). Um grupo recebeu apenas inoculação por Candida (grupo PL-, controle positivo), outro grupo não recebeu nenhum tratamento e nem inoculação fúngica (grupo CN ­ controle negativo). Após os experimentos realizou-se a recuperação de C. albicans das línguas dos animais por meio de swabs que foram esfregados sobre as mesmas durante 1 minuto. Esses swabs foram embebidos em tubos de ensaio com 1mL de solução salina, e diluições seriadas foram realizadas e colocadas em placas de petri com SDA. Após 48 horas de incubação a 37º C as células fúngicas foram quantificadas e o número de Ufc/mL foi determinado e analisado pelo teste ANOVA (P<.05). Os camundongos foram sacrificados e tiveram as línguas removidas cirurgicamente para realização da análise histológica. Os resultados demonstraram que a PDT foi efetiva na redução da viabilidade celular da C. albicans coletadas das línguas dos animais nas concentrações de 100, 125 e 150mg/L de FS, quando comparados com os animais do grupo controle positivo (P-L-) (P<0.05). Entretanto não houve diferença significativa entre os grupos que receberam PDT (P+L+100, P+L+125 e P+L+150mg/L). De acordo com os resultados pode-se concluir que a PDT não causou efeitos adversos nos tecidos das línguas dos animais. Dessa forma, concluiu-se que a PDT foi efetiva na inativação de C. albicans sem causar qualquer dano aos tecidos das línguas dos animais

The aim of this investigation was to evaluate the effectiveness of photodynamic therapy (PDT) mediated by photossensitizer Photodithazine® (PDZ) associated with LED light (660nm) for the photoinactivation of C. albicans in a murine model of oral candidosis. Fifty-five 6-week-old female Swiss mice were immunossuppressed and in the next day small cotton pads were soaked in a C. albicans cell suspension (107 CFU/mL) and swabbed in the oral cavity of mice. PDT was performed and the PS was applicated topically on the dorsum of the tongue of mice at concentrations 75, 100, 125 and 150mg/L (P+L+75, P+L+100, P+L+125 and P+L+150mg/L) associated with LED at a fluence of 37,5J/cm2 . The effect of PS only was tested by application of PDZ for the same period of pre-irradiation time and irradiation at the same concentration as that for the P+L+ group, without the LED illumination (P+L-75, P+L-100, P+L-125 and P+L-150mg/L). To verify the effect of the light only, the group was exposed to the same LED dose mentioned previously (P-L+ 37,5J/cm2 ), 1 group). The positive control did not receive any PS or light (P-L-). The negative control group (CN) of animals was evaluated and mice did not receive any treatment. After treatment the dorsum of the tongue was swabbed for 1 minute with a cotton pad to recover C. albicans cells and the microbiological evaluation was performed. The yeast colony counts were quantified and the number of CFU/mL was determined and analyzed by ANOVA test (P<.05). Animals were killed 24 hours after treatment and the tongue of all mice were surgically removed for histological analysis. The results of this investigation demonstrated that PDT was effective in reducing C. albicans recovered from the tongue of mice at concentrations 100, 125 and 150mg/L of PS when compared with the animals from the positive control group (P-L-) (P<0.05). There was no difference between these concentrations. Histological analyze was performed and no adverse effect on the tongue tissue was induced by PDT. In conclusion, PDT was effective for inactivation of C. albicans without causing any harming effects on tissues