Biofilms of Candida albicans and Streptococcus sanguinis and their susceptibility to antimicrobial effects of photodynamic inactivation.

This study evaluated the effects of photodynamic inactivation (PDI) on single and multi-species biofilms, compounds by Candida albicans and Streptococcus sanguinis. Biofilms were formed, on microplate of 96 wells, by suspensions of C. albicans (ATCC 18804) and S. sanguinis (ATCC 7073) adjusted in 107 cells/mL, followed by incubation of 48 h (with 5% CO2). The effects of the photosensitizer erythrosine (ER) at 400 µM for 5 min and green light-emitting diode (LED - 532 ±â€¯10 nm) for 3 min, alone and conjugated, were evaluated. After normality test, results was analysed by Tukey´s test (P < 0.05). PDI group promoted reductions of 1.07 and 0.39 log10, respectively, in biofilms of C. albicans alone and in association with S. sanguinis. Biofilms of S. sanguinis alone were more sensitive, with reduction of 4.48 log10. When in association with the yeast, S. sanguinis have a decrease of 2.67 log10. SEM analysis revealed a decrease in bacterial and fungal structures of biofilms treated with PDI. In conclusion PDI promoted significant microbial reductions in both species of microorganisms grown on mixed biofilms. This study is one of the pioneers to evaluate the antimicrobial action of PDI on biofilms of S. sanguinis and C. albicans, demonstrating a way to control these microorganisms of clinical importance.

Photodynamic inactivation in the expression of the Candida albicans genes ALS3, HWP1, BCR1, TEC1, CPH1, and EFG1 in biofilms.

The objective of this study was to evaluate the effects of photodynamic inactivation (PDI) on Candida albicans biofilms, evaluating its effects on gene expression of ALS3, HWP1, BCR1, TEC1, CPH1, and EFG1 by yeast. Three samples of C. albicans were used in this study: a clinical sample from a patient with HIV (39S), a clinical sample from a patient with denture stomatitis lesion (Ca30), and a standard strain ATCC 18804. The quantification of gene expression was related to the production of those genes in the samples referred above using quantitative polymerase chain reaction (qPCR) assay in real time. The photosensitizer methylene blue at 300 uM and erythrosine at 400 uM, sensitized with low-power laser (visible red, 660 nm) and green LED (532 nm), respectively, were used for PDI. Four groups of each sample and PDI protocol were evaluated: (a) P+L+: sensitization with the photosensitizer and irradiation with light, (b) P+L-: only treatment with the photosensitizer, (c) P-L+: only irradiation with light, and (d) P-L-: without sensitization with the dye and absence of light. The results were analyzed by t test, with a significance level of 5%. The photodynamic inactivation was able to reduce the expression of all genes for both treatments, laser and LED. The fold-decrease for the genes ALS3, HWP1, BCR1, TEC1, CPH1, and EFG1 were 0.73, 0.39, 0.77, 0.71, 0.67, and 0.60 for laser, respectively, and 0.66, 0.61, .050, 0.43, 0.54, and 0.66 for LED, respectively. It could be concluded that PDI showed a reduction in the expression of C. albicans genes, suggesting its virulence decrease.

Bacterial adhesion on conventional and self-ligating metallic brackets after surface treatment with plasma-polymerized hexamethyldisiloxane.

INTRODUCTION:: Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion. METHODS:: Hexamethyldisiloxane (HMDSO) polymer films were deposited on conventional (n = 10) and self-ligating (n = 10) stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD) radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM) analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region) and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI) and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test. RESULTS:: Significant statistical differences (p< 0.05) for surface roughness and bacterial adhesion reduction were observed on conventional brackets after surface treatment and between conventional and self-ligating brackets; no significant statistical differences were observed between self-ligating groups (p> 0.05). CONCLUSION:: Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film.

Bacterial adhesion on conventional and self-ligating metallic brackets after surface treatment with plasma-polymerized hexamethyldisiloxane

ABSTRACT Introduction: Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion. Methods: Hexamethyldisiloxane (HMDSO) polymer films were deposited on conventional (n = 10) and self-ligating (n = 10) stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD) radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM) analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region) and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI) and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test. Results: Significant statistical differences (p< 0.05) for surface roughness and bacterial adhesion reduction were observed on conventional brackets after surface treatment and between conventional and self-ligating brackets; no significant statistical differences were observed between self-ligating groups (p> 0.05). Conclusion: Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film.

RESUMO Introdução: a deposição de filme de polímero a plasma foi criada para modificar as propriedades de superfície dos braquetes ortodônticos metálicos, com o intuito de inibir a adesão bacteriana. Métodos: filmes finos de polímero de hexametildisiloxano (HMDSO) foram depositados em braquetes ortodônticos de aço inoxidável convencionais (n = 10) e autoligáveis (n = 10), utilizando a técnica de radiofrequência PECVD (Plasma-Enhanced Chemical Vapor Deposition). As amostras foram divididas em dois grupos, de acordo com o tipo de braquete, e dois subgrupos após o tratamento de superfície. A microscopia eletrônica de varredura (MEV) foi realizada para avaliar a presença de adesão bacteriana sobre as superfícies das amostras (região de ranhura horizontal e aletas) e a integridade da camada de filme. A Interferometria Confocal (CI) avaliou a rugosidade, e a molhabilidade superficial foi avaliada por goniometria. Para análise de adesão bacteriana, as amostras foram expostas durante 72 horas a uma solução de Streptococcus mutans, para formação de biofilme. Os valores obtidos para a rugosidade da superfície foram analisados pelo teste de Mann-Whitney, enquanto a adesão do biofilme foi avaliada pelos testes de Kruskal-Wallis e SNK. Resultados: observaram-se diferenças estatisticamente significativas (p <0,05) para a rugosidade superficial e redução da adesão bacteriana em braquetes convencionais após o tratamento da superfície, e entre braquetes convencionais e autoligáveis. Não foram observadas diferenças estatísticas significativas entre os grupos autoligáveis (p> 0,05). Conclusão: a deposição de polímero a plasma só foi efetiva na redução da rugosidade superficial e adesão bacteriana em braquetes convencionais. Observou-se, também, que os braquetes convencionais apresentaram menor adesão ao biofilme do que os braquetes autoligáveis, apesar da ausência de filme.

Influence of sucrose on growth and sensitivity of Candida albicans alone and in combination with Enterococcus faecalis and Streptococcus mutans to photodynamic therapy.

This study has evaluated the effects of photodynamic inactivation (PDI) using erythrosine as photosensitizer and green light-emitting diode (LED) on biofilms of Candida albicans alone and in combination with Enterococcus faecalis and Streptococcus mutans. We have also evaluated the effect of sucrose on biofilm formation and bacterial growth and sensitivity to PDI. Biofilms were formed in suspension of 106 cells/ml on plates before being grown in broth culture with and without sucrose and incubated for 48 h. Next, the treatment was applied using erythrosine at a concentration of 400 µM for 5 min and green LED (532 ± 10 nm) for 3 min on biofilms alone and in combination. The plates were washed and sonicated to disperse the biofilms, and serial dilutions were carried and aliquots seeded in Sabouraud agar before incubation for 48 h. Next, the colony-forming units per milliliter (CFU/ml; log10) were counted and analyzed statistically (ANOVA, Tukey test, P ≤ 0.05). Results show that S. mutans favors the growth of C. albicans in biofilms with sucrose, with treatment not being effective. However, when the biofilm was grown without sucrose, we found a reduction in biofilm formation and a significant decrease in the PDI treatment (P < 0.0001). In conclusion, both growth and sensitivity to PDI in biofilms of C. albicans are strongly influenced by bacterial combination, and the presence of sucrose affected directly the growth and sensitivity of the biofilm to PDI as sucrose is the substrate for construction of the exopolysaccharide matrix.

Antibiofilm activity in vitro of Rosmarinus officinalis and Syzygium cumini glycolic extracts on Staphylococcus spp. of dentistry interest / Atividade antibiofilme in vitro dos extratos glicólicos de Rosmarinus officinalis e Syzygium cumini em Staphylococcus spp. de interesse odontológico

Objectives: The aim of this study was to identify the slime production and evaluate the effects of Rosmarinus officinalis (rosemary) and Syzygium cumini (jambolan) glycolic extracts, and 0.12% chlorhexidine (CHX) in biofilms formed by strains of coagulase-positive Staphylococcus - CPS and coagulase negative Staphylococcus - CNS isolated from the oral cavity. Material and Methods: Slime production was evaluated by two methods: the color of colony presented in Congo red agar, and through the amount of slime adhered to polystyrene. Biofilms were grown in acrylic resin discs immersed in broth, inoculated with microbial suspension (106 cells/ml) and incubated at 37°C/48 h. After formation, the biofilms were exposed for 5 minutes to glycol extracts, CHX or saline solution. The viability of biofilms was determined by counting the colony-forming units per milliliter (CFU/ml) in agar, and analyzed statistically by Tukey test (p< 0.05). Results: The strains S. aureus, S. schleiferi and S. epidermidis obtained the highest values of slime adhered to polystyrene. R. officinalis promoted reductions ranging from 12.1% to 78.7% in biofilms formed by isolates of CPS, and 9.2% to 73.7% in the biofilms of CNS. S. cumini reduced 12% to 55.7% in biofilms of CPS, and 7.9% to 71.5% in biofilms of CNS. With exception of S. saprophyticus, glycol extracts produced significant reductions in biofilms. For five isolates studied, R. officinalis produced greater reductions than CHX. Conclusion: R. officinalis and S. cumini showed effective antibiofilm activity against isolates that showed slime production.(AU)

Objetivos: O objetivo deste estudo foi identificar a produção de slime e avaliar os efeitos dos extratos glicólicos de Rosmarinus officinalis (alecrim), Syzygium cumini (jambolão) e 0,12% de clorexidina (CLX) em biofilmes formados por cepas de Staphylococcus coagulase positivo (SCP) e Staphylococcus coagulase negativo (SCN) da cavidade oral. Material e Métodos: A produção de slime foi avaliada por dois métodos: a cor da colônia apresentada em ágar vermelho Congo e pela quantidade de slime aderido ao poliestireno. Os biofilmes foram crescidos em discos de resina acrílica imersos em caldo, inoculados com suspensão microbiana (106 células/ml) e incubados a 37°C/48h. Após a formação, os biofilmes foram expostos durante 5 minutos aos extractos glicólicos, CLX ou solução salina. A viabilidade dos biofilmes foi determinada pela contagem das unidades formadoras de colônias por mililitro (UFC/ml) em ágar e analisada estatisticamente pelo teste de Tukey (p< 0,05). Resultados: As cepas S. aureus, S. schleiferi e S. epidermidis obtiveram os maiores valores de aderência ao poliestireno. R. officinalis promoveu reduções variando de 12,1% a 78,7% em biofilmes formados por isolados de SCP e 9,2% a 73,7% nos biofilmes de SCN. S. cumini reduziu de 12% a 55,7% nos biofilmes de SCP, e 7,9% a 71,5% nos biofilmes de SCN. Com exceção de S. saprophyticus, os extratos glicólicos produziram reduções estatísticas nos biofilmes. Para cinco isolados estudados, R. officinalis produziu maiores reduções do que CLX. Conclusão: R. officinalis e S. cumini mostraram atividade antibiofilme efetiva contra isolados que apresentaram produção de slime.(AU)

Candida/Candida biofilms. First description of dual-species Candida albicans/C. rugosa biofilm.

Denture liners have physical properties that favour plaque accumulation and colonization by Candida species, irritating oral tissues and causing denture stomatitis. To isolate and determine the incidence of oral Candida species in dental prostheses, oral swabs were collected from the dental prostheses of 66 patients. All the strains were screened for their ability to form biofilms; both monospecies and dual-species combinations were tested. Candida albicans (63 %) was the most frequently isolated microorganism; Candida tropicalis (14 %), Candida glabrata (13 %), Candida rugosa (5 %), Candida parapsilosis (3 %), and Candida krusei (2 %) were also detected. The XTT assay showed that C. albicans SC5314 possessed a biofilm-forming ability significantly higher (p < 0.001) than non-albicans Candida strains, after 6 h 37 °C. The total C. albicans CFU from a dual-species biofilm was less than the total CFU of a monospecies C. albicans biofilm. In contrast to the profuse hyphae verified in monospecies C. albicans biofilms, micrographies showed that the C. albicans/non-albicans Candida biofilms consisted of sparse yeast forms and profuse budding yeast cells that generated a network. These results suggested that C. albicans and the tested Candida species could co-exist in biofilms displaying apparent antagonism. The study provide the first description of C. albicans/C. rugosa mixed biofilm.

Production of virulence factors in Candida strains isolated from patients with denture stomatitis and control individuals.

The aim of this study was to evaluate the production of virulence factors in Candida isolates from the oral cavities of 50 patients with different degrees of denture stomatitis (DS, type I, II and III) and 50 individuals without signs of DS. We evaluated the enzymatic and hemolytic activities, the biofilm formation, and the cell surface hydrophobicity (CSH) in all isolates. Germ tube (GT) production was also evaluated in Candida albicans and Candida dubliniensis isolates. In C. albicans and C. dubliniensis the secretion of hemolysin and GT production was significantly different between isolates from patients with DS and individuals without DS. No significant difference was observed in the production of virulence factors by Candida glabrata isolates. Candida isolates expressed a wide range of virulence factors. However, in the majority of isolates from the type III lesions, the production of the virulence factors was higher than for the other groups.

Photodynamic inactivation of virulence factors of Candida strains isolated from patients with denture stomatitis.

Candida species are major microorganisms isolated in denture stomatitis (DS), an inflammatory process of the mucosa underlying removable dental prostheses, and express a variety of virulence factors that can increase their pathogenicity. The potential of Photodynamic inactivation (PDI) in planktonic culture, biofilms and virulence factors of Candida strains was evaluated. A total of 48 clinical Candida isolates from individuals wearing removable maxillary prostheses with DS were included in the study. The effects of erythrosine (ER, 200 µM) and a green LED (λ 532 ± 10 nm, 237 mW/cm(2) and 42.63 J/cm(2)) in a planktonic culture were evaluated. The effect of the addition of ER at a concentration of 400 µM together with a green LED was evaluated in biofilms. The virulence factors of all of the Candida strains were evaluated before and after the PDI process in cells derived from biofilm and planktonic assays. All of the Candida species were susceptible to ER and green LED. However, the biofilm structures were more resistant to PDI than the planktonic cultures. PDI also promoted slight reductions in most of the virulence factors of C. albicans and some of the Candida tropicalis strains. These results suggest that the addition of PDI is effective for reducing yeasts and may also reduce the virulence of certain Candida species and decrease their pathogenicity.

The antimicrobial effects of Citrus limonum and Citrus aurantium essential oils on multi-species biofilms.

The aim of this study was to evaluate the effects of Citrus limonum and Citrus aurantium essential oils (EOs) compared to 0.2% chlorhexidine (CHX) and 1% sodium hypochlorite (NaOCl) on multispecies biofilms formed by Candida albicans, Enterococcus faecalis and Escherichia coli. The biofilms were grown in acrylic disks immersed in broth, inoculated with microbial suspension (106 cells/mL) and incubated at 37°C / 48 h. After the biofilms were formed, they were exposed for 5 minutes to the solutions (n = 10): C. aurantium EO, C. limonum EO, 0.2% CHX, 1% NaOCl or sterile saline solution [0.9% sodium chloride NaCl)]. Next, the discs were placed in sterile 0.9% NaCl and sonicated to disperse the biofilms. Tenfold serial dilutions were performed and the aliquots were seeded onto selective agar and incubated at 37°C / 48 h. , the number of colony-forming units per milliliter was counted and analyzed statistically (Tukey test, p ≤ 0.05). C. aurantium EO and NaOCl inhibited the growth of all microorganisms in multi-species biofilms. C. limonum EO promoted a 100% reduction of C. albicans and E. coli, 49.3% of E. faecalis. CHX was less effective against C. albicans and E. coli, yielding a reduction of 68.8% and 86.7%, respectively. However, the reduction of E. faecalis using CHX (81.7%) was greater than that obtained using C. limonum EO. Both Citrus limonum and Citrus aurantium EOs are effective in controlling multi-species biofilms; the microbial reductions achieved by EOs were not only similar to those of NaOCl, but even higher than those achieved by CHX, in some cases.

The antimicrobial effects of Citrus limonum and Citrus aurantium essential oils on multi-species biofilms

The aim of this study was to evaluate the effects of Citrus limonum and Citrus aurantium essential oils (EOs) compared to 0.2% chlorhexidine (CHX) and 1% sodium hypochlorite (NaOCl) on multi-species biofilms formed by Candida albicans, Enterococcus faecalis and Escherichia coli. The biofilms were grown in acrylic disks immersed in broth, inoculated with microbial suspension (106 cells/mL) and incubated at 37°C / 48 h. After the biofilms were formed, they were exposed for 5 minutes to the solutions (n = 10): C. aurantium EO, C. limonum EO, 0.2% CHX, 1% NaOCl or sterile saline solution [0.9% sodium chloride (NaCl)]. Next, the discs were placed in sterile 0.9% NaCl and sonicated to disperse the biofilms. Tenfold serial dilutions were performed and the aliquots were seeded onto selective agar and incubated at 37°C / 48 h. Next, the number of colony-forming units per milliliter was counted and analyzed statistically (Tukey test, p ≤ 0.05). C. aurantium EO and NaOCl inhibited the growth of all microorganisms in multi-species biofilms. C. limonum EO promoted a 100% reduction of C. albicans and E. coli, and 49.3% of E. faecalis. CHX was less effective against C. albicans and E. coli, yielding a reduction of 68.8% and 86.7%, respectively. However, the reduction of E. faecalis using CHX (81.7%) was greater than that obtained using C. limonum EO. Both Citrus limonum and Citrus aurantium EOs are effective in controlling multi-species biofilms; the microbial reductions achieved by EOs were not only similar to those of NaOCl, but even higher than those achieved by CHX, in some cases.

Comparison of the effect of rose bengal- and eosin Y-mediated photodynamic inactivation on planktonic cells and biofilms of Candida albicans.

Candida albicans is an opportunistic yeast that can cause oral candidosis through the formation of a biofilm, an important virulence factor that compromises the action of antifungal agents. The objective of this study was to compare the effect of rose bengal (RB)- and eosin Y (EY)-mediated photodynamic inactivation (PDI) using a green light-emitting diode (LED; 532 ± 10 nm) on planktonic cells and biofilms of C. albicans (ATCC 18804). Planktonic cultures were treated with photosensitizers at concentrations ranging from 0.78 to 400 µM, and biofilms were treated with 200 µM of photosensitizers. The number of colony-forming unit per milliliter (CFU/mL) was compared by analysis of variance and Tukey's test (P ≤ 0.05). After treatment, one biofilm specimen of the control and PDI groups were examined by scanning electron microscopy. The photosensitizers (6.25, 25, 50, 200, and 400 µM of EY, and 6.25 µM of RB or higher) significantly reduced the number of CFU/mL in the PDI groups when compared to the control group. With respect to biofilm formation, RB- and EY-mediated PDI promoted reductions of 0.22 log10 and 0.45 log10, respectively. Scanning electron microscopy showed that the two photosensitizers reduced fungal structures. In conclusion, EY- and RB-mediated PDI using LED irradiation significantly reduced C. albicans planktonic cells and biofilms.

Opportunistic microorganisms in individuals with lesions of denture stomatitis.

The aim of this study was to isolate, quantify, identify, and compare opportunistic microorganisms (Candida and Staphylococcus genera and Enterobacteriaceae/Pseudomonadaceae families) from prosthesis-fitting surfaces, the hard palate, and mouth rinses of individuals wearing removable maxillary prosthesis with (50) and without (50) lesions of denture stomatitis (DS). The strains were collected and identified using phenotypic, biochemical and molecular tests. The counts of microorganisms were significantly higher in the group of individuals with DS (P < 0.05). C. albicans was the most frequently isolated yeast species in both groups, following by C. tropicalis and C. glabrata. Six isolates were identified as C. dubliniensis. S. aureus and S. epidermidis were the most frequent Staphylococcus species in both groups. Klebsiella pneumoniae was the predominant species in both groups. The association between Candida spp. and bacteria isolated in this study with DS suggests that these microorganisms may play important roles in the establishment and persistence of this disease.

Photodynamic inactivation of Streptococcus mutans and Streptococcus sanguinis biofilms in vitro.

The purpose of this study was to evaluate specific effects of photodynamic inactivation (PDI) using erythrosine (ER) and Rose Bengal (RB) photosensitizers and a blue light-emitting diode (LED) on the viability of Streptococcus mutans and Streptococcus sanguinis biofilms. Biofilms were grown in acrylic disks immersed in broth to production of biofilms, inoculated with microbial suspension (10(6) cells/mL) and incubated for 48 h. After the formation of biofilms, the effects of the photosensitizers ER and RB at a concentration of 5 µM for 5 min and blue LED (455 ± 20 nm) for 180 s, photosensitizers alone and conjugated were evaluated. Next, the disks were placed in tubes with sterile physiological solution (0.9 % sodium chloride) and sonicated for to disperse the biofilms. Tenfold serial dilutions were carried and aliquots seeded in brain heart infusion agar which were then incubated for 48 h. Then the numbers colony-forming units per milliliter (CFU/mL; log10) were counted and analyzed statistically (ANOVA, Tukey test, P ≤ 0.05). Significant decreases in the viability of all microorganisms were observed for biofilms exposed to PDI mediated by both photosensitizers. The reductions with RB and ER were, 0.62 and 0.52 log10 CFU mL(-1) for S. mutans biofilms (p=0.001), and 0.95 and 0.88 log10 CFU mL(-1) for S. sanguinis biofilms (p=0.001), respectively. The results showed that biofilms formed in vitro by S. mutans and S. sanguinis, were sensitive to PDI using a blue LED associated with photosensitizers ER or RB, indicating its use in the control of caries and periodontal diseases.

Effect of erythrosine- and LED-mediated photodynamic therapy on buccal candidiasis infection of immunosuppressed mice and Candida albicans adherence to buccal epithelial cells.

OBJECTIVE: This study evaluated the effects of photodynamic therapy (PDT) on buccal candidiasis in mice and on the adherence of yeast to buccal epithelial cells (BECs) in vitro. STUDY DESIGN: A total of 56 immunosuppressed mice with buccal candidiasis were subjected to PDT, consisting of treatment with erythrosine (400 µmol/L) followed by exposure to a green LED (14.34 J cm(-2)). After treatment, the yeasts recovered from the mice were quantified (CFU/mL) and analyzed for the effects of PDT on their adherence to BECs. The data were analyzed using ANOVA, the Tukey test, Kruskal-Wallis test and Student t test. RESULTS: PDT significantly reduced the amount of yeast present in the lesions by 0.73 log(10) (P = .018) and reduced C. albicans adherence to BECs by 35% without damaging adjacent tissues (P = .045). CONCLUSIONS: Photodynamic therapy exhibited antifungal effects against C. albicans biofilms formed in vivo and reduced the capacity of C. albicans to adhere to BECs in vitro.

Morphology and bacterial colonisation of tooth/ceramic restoration interface after different cement excess removal techniques.

OBJECTIVES: To evaluate the influence of different protocols for resin cement removal during cementation on biofilm formation. METHODS: Twenty-eight ceramic blocks, which were injected under pressure, were placed over enamel blocks obtained from freshly extracted bovine incisors. The ceramic blocks were cemented to the enamel blocks using a dual-cured resin cement and the excess resin was removed according to the experimental group: TS: Teflon spatula; BR: brush; BR+: brush and polishing; SB+: scalpel blade and polishing. After autoclaving, the samples were colonised by incubation in a sucrose broth suspension standardised with Streptococcus mutans in microaerophilic stove. Specimens were quantitatively analysed for bacterial adherence at the adhesive interface using confocal laser scanning microscopy and counting the colony forming units, and qualitatively analysed using SEM. The roughness (Ra/Rz/RSm) was also analysed. Data were analysed by 1-way ANOVA and Tukey's test (5%). RESULTS: The roughness values ranged from 0.96 to 1.69 µm for Ra (p>0.05), from 11.59 to 22.80 µm for Rz (p=0.02<0.05) and from 293.2 to 534.3 µm for RSm (p=0.00). Bacterial adhesion varied between 1,974,000 and 2,814,000 CFU/ml (p=0.00). Biofilm mean thickness ranged from 0.477 and 0.556 µm (p>0.05), whilst the biovolume values were between 0.388 and 0.547 µm(3)/µm(2) (p=0.04). Lower values for roughness, bacterial adhesion, biofilm thickness and biovolume were found with BR, whilst TS presented the highest values for most of the parameters. SEM images confirmed the quantitative values. CONCLUSIONS: The restoration margin morphology and interface roughness affects bacterial accumulation. The brush technique promoted less bacterial colonisation at the adhesive interface than did the other removal methods. CLINICAL SIGNIFICANCE: The brush technique seems to be a good option for removing the excess resin cement after adhesive cementation in clinical practice, as indicated by its better results with lower bacterial colonisation.

The effects of rose bengal- and erythrosine-mediated photodynamic therapy on Candida albicans.

The aim of this study was to evaluate the effects of photodynamic therapy (PDT) using rose bengal or erythrosine with light emitting diode (LED) on Candida albicans planktonic cultures and biofilms. Seven C. albicans clinical strains and one standard strain (ATCC 18804) were used. Planktonic cultures and biofilms of each C. albicans strain were submitted to the following experimental conditions: (a) treatment with rose bengal and LED (RB+L+); (b) treatment with erythrosine and LED (E+L+); and (c) control group, without LED irradiation or photosensitiser treatment (P-L-). After irradiation of the planktonic cultures and biofilms, the cultures were seeded onto Sabouraud dextrose agar (37 °C at 48 h) for counting of colony-forming units (CFU ml(-1) ) followed by posterior anova and Tukey's test analyses (P < 0.05). The biofilms were analysed using scanning electron microscopy (SEM). The results revealed a significant reduction of planktonic cultures (3.45 log(10) and 1.97 log(10) ) and of biofilms (<1 log(10) ) for cultures that were subjected to PDT mediated using either erythrosine or rose bengal, respectively. The SEM data revealed that the PDT was effective in reducing and destroying of C. albicans blastoconidia and hyphae. The results show that erythrosine- and rose bengal-mediated PDT with LED irradiation is effective in treating C. albicans.

Antimicrobial activity of Calendula officinalis, Camellia sinensis and chlorhexidine against the adherence of microorganisms to sutures after extraction of unerupted third molars.

OBJECTIVE: The objective of this study was to compare the antimicrobial effect of mouthwashes containing Calendula officinalis L., Camellia sinensis (L.) Kuntze and 0.12% chlorhexidine digluconate on the adherence of microorganisms to suture materials after extraction of unerupted third molars. MATERIAL AND METHODS: Eighteen patients with unerupted maxillary third molars indicated for extraction were selected (n=6 per mouthwash). First, the patients were subjected to extraction of the left tooth and instructed not to use any type of antiseptic solution at the site of surgery (control group). After 15 days, the right tooth was extracted and the patients were instructed to use the Calendula officinalis, Camellia sinensis or chlorhexidine mouthwash during 1 week (experimental group). For each surgery, the sutures were removed on postoperative day 7 and placed in sterile phosphate-buffered saline. Next, serial dilutions were prepared and seeded onto different culture media for the growth of the following microorganisms: blood agar for total microorganism growth; Mitis Salivarius bacitracin sucrose agar for mutans group streptococci; mannitol agar for Staphylococcus spp.; MacConkey agar for enterobacteria and Pseudomonas spp., and Sabouraud dextrose agar containing chloramphenicol for Candida spp. The plates were incubated during 24-48 h at 37ºC for microorganism count (CFU/mL). RESULTS: The three mouthwashes tested reduced the number of microorganisms adhered to the sutures compared to the control group. However, significant differences between the control and experimental groups were only observed for the mouthwash containing 0.12% chlorhexidine digluconate. CONCLUSIONS: Calendula officinalis L. and Camellia sinensis (L.) Kuntze presented antimicrobial activity against the adherence of microorganisms to sutures but were not as efficient as chlorhexidine digluconate.

Antimicrobial activity of Calendula officinalis, Camellia sinensis and chlorhexidine against the adherence of microorganisms to sutures after extraction of unerupted third molars

OBJECTIVE: The objective of this study was to compare the antimicrobial effect of mouthwashes containing Calendula officinalis L., Camellia sinensis (L.) Kuntze and 0.12 percent chlorhexidine digluconate on the adherence of microorganisms to suture materials after extraction of unerupted third molars. MATERIAL AND METHODS: Eighteen patients with unerupted maxillary third molars indicated for extraction were selected (n=6 per mouthwash). First, the patients were subjected to extraction of the left tooth and instructed not to use any type of antiseptic solution at the site of surgery (control group). After 15 days, the right tooth was extracted and the patients were instructed to use the Calendula officinalis, Camellia sinensis or chlorhexidine mouthwash during 1 week (experimental group). For each surgery, the sutures were removed on postoperative day 7 and placed in sterile phosphate-buffered saline. Next, serial dilutions were prepared and seeded onto different culture media for the growth of the following microorganisms: blood agar for total microorganism growth; Mitis Salivarius bacitracin sucrose agar for mutans group streptococci; mannitol agar for Staphylococcus spp.; MacConkey agar for enterobacteria and Pseudomonas spp., and Sabouraud dextrose agar containing chloramphenicol for Candida spp. The plates were incubated during 24-48 h at 37ºC for microorganism count (CFU/mL). RESULTS: The three mouthwashes tested reduced the number of microorganisms adhered to the sutures compared to the control group. However, significant differences between the control and experimental groups were only observed for the mouthwash containing 0.12 percent chlorhexidine digluconate. CONCLUSIONS: Calendula officinalis L. and Camellia sinensis (L.) Kuntze presented antimicrobial activity against the adherence of microorganisms to sutures but were not as efficient as chlorhexidine digluconate.

Susceptibility of Candida albicans and Candida dubliniensis to erythrosine- and LED-mediated photodynamic therapy.

The effect of erythrosine- and LED-mediated photodynamic therapy (PDT) on planktonic cultures and biofilms of Candida albicans and Candida dubliniensis was evaluated. Planktonic cultures of standardized suspensions (10(6)cells/mL) of C. albicans and C. dubliniensis were treated with erythrosine concentrations of 0.39-200 µM and LEDs in a 96-well microtiter plate. Biofilms formed by C. albicans and C. dubliniensis in the bottom of a 96-well microtiter plate were treated with 400 µM erythrosine and LEDs. After PDT, the biofilms were analysed by scanning electron microscopy (SEM). The antimicrobial effect of PDT against planktonic cultures and biofilms was verified by counting colony-forming units (CFU/mL), and the data were submitted to analysis of variance and the Tukey test (P<0.05). C. albicans and C. dubliniensis were not detectable after PDT of planktonic cultures with erythrosine concentrations of 3.12 µM or higher. The CFU/mL values obtained from biofilms were reduced 0.74 log(10) for C. albicans and 0.21 log(10) for C. dubliniensis. SEM revealed a decrease in the quantity of yeasts and hyphae in the biofilm after PDT. In conclusion, C. albicans and C. dubliniensis were susceptible to erythrosine- and LED-mediated PDT, but the biofilms of both Candida species were more resistant than their planktonic counterparts.