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.

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)

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.

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 planktonic cultures of Streptococcus mutans to photodynamic therapy with a light-emitting diode

The objective of this study was to evaluate the effect of photodynamic therapy with erythrosine and rose bengal using a light-emitting diode (LED) on planktonic cultures of S. mutans. Ten S. mutans strains, including nine clinical strains and one reference strain (ATCC 35688), were used. Suspensions containing 10(6) cells/mL were prepared for each strain and were tested under different experimental conditions: a) LED irradiation in the presence of rose bengal as a photosensitizer (RB+L+); b) LED irradiation in the presence of erythrosine as a photosensitizer (E+L+); c) LED irradiation only (P-L+); d) treatment with rose bengal only (RB+L-); e) treatment with erythrosine only (E+L-); and f) no LED irradiation or photosensitizer treatment, which served as a control group (P-L-). After treatment, the strains were seeded onto BHI agar for determination of the number of colony-forming units (CFU/mL). The results were submitted to analysis of variance and the Tukey test (p < 0.05). The number of CFU/mL was significantly lower in the groups submitted to photodynamic therapy (RB+L+ and E+L+) compared to control (P-L-), with a reduction of 6.86 log10 in the RB+L+ group and of 5.16 log10 in the E+L+ group. Photodynamic therapy with rose bengal and erythrosine exerted an antimicrobial effect on all S. mutans strains studied.

Ação antimicrobiana in vitro de extratos glicólicos de Psidium guajava L., Syzygium cumini L e Pimpinella anisum L / In vitro antimicrobial action of extracts glicolics of Psidium guajava L., Syzygium cumini L and Pimpinella anisum L

Várias pesquisas vêm sendo desenvolvidas e direcionadas no descobrimento de novos agentes antimicrobianos provenientes de plantas, para serem aplicados em produtos farmacêuticos. O objetivo deste estudo foi avaliar in vitro a propriedade antimicrobiana de extratos glicólicos (75%) de Psidium guajava L. (goiabeira), Syzygium cumini L. (jambolão) e Pimpinella anisum L. (erva-doce) sobre cepas padrão de Candida albicans, Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans, Escherichia coli e Bacillus atrophaeus (esporos). Foi determinada a concentração inibitória mínima (CIM) pelo método de microdiluição em caldo, seguindo-se de subcultivos e magar para determinar a concentração microbicida mínima (CMM). Os extratos apresentaram as seguintes CIM e CMM, respectivamente: goiabeira 25% e 50% para C. albicans, E. faecalis e E. coli; 12,5% e 25% para S. mutans, e, 3,12% e 6,25% para S. aureus; jambolão 25% e 50% para C. albicans, 12,5% e 25% para E. faecalis e S. aureus, e, 6,25% e 12,5% para E. coli e S. mutans; erva-doce 12,5% e 25% para C. albicans e S. mutans, 6,25% e 12,5% para E. faecalis e S. aureus, e 3,12% e 6,25% para E. coli. Conclui-se que, apesar da resistência apresentada por B. atrophaeus, os extratos utilizados demonstraram potencial antimicrobiano sobre os demais micro-organismos.

Atividade antifúngica dos extratos glicólicos de Rosmarinus officinalis Linn. e Syzygium cumini Linn. sobre cepas clínicas de Candida albicans, Candida glabrata e Candida tropicalis / Antifungal activity of glycolics extracts of Rosmarinus officinalis Linn. and Syzygium cumini Linn. on clinical strains of Candida albicans, Candida glabrata and Candida tropicalis

O objetivo deste estudo consiste em avaliar in vitro o potencial antifúngico dos extratos glicólicos de Rosmarinus officinalis Linn. (alecrim) e Syzygium cumini Linn. (jambolão) sobre cepas clínicas de Candida albicans (n = 14), Candida glabrata (n = 8) e Candida tropicalis (n = 8). A Concentração Inibitória Mínima (CIM) foi determinada por meio de diluições seriadas dos extratos (100 a 3,125 mg.mL­1) em caldo Sabouraud, que foram posteriormente inoculados com suspensões fúngicas (106 células.mL­1). Estes ensaios permaneceram incubados a 37 °C, por 24 horas. Após o período de incubação, os ensaios que não apresentaram crescimento no caldo foram semeados em ágar Sabouraud e incubados a 37 °C por 48 horas, para determinar a Concentração FungicidaMínima (CFM). Para a maioria das cepas estudadas, a CIM do extrato de Rosmarinus officinalis Linn. foi similar ao extrato de Syzygium cumini Linn., correspondendo a 25 mg.mL­1 para C. albicans, 25 mg.mL­1 para C. glabrata e 12,5 mg.mL­1 para C. tropicalis. Os valores de CFM dos extratos de Rosmarinus officinalis Linn. e Syzygium cumini Linn. foram, respectivamente, 25 e 50 mg. mL­1 para C. albicans, 50 mg.mL­1 para C. glabrata e 25 mg.mL­1 para C. tropicalis. Conclui-se que os extratos glicólicos de Rosmarinus officinalis Linn. e Syzygium cumini Linn. apresentaram potencial antifúngico para todas as cepas de Candida estudadas, sendo que as cepas de C. tropicalis demonstraram-se mais sensíveis aos extratos em relação a C. albicans e C. glabrata.

The aim of this study was to evaluate in vitro antifungal potential of extracts glycolics Rosmarinus officinalis Linn. (rosemary) and Syzygium cumini Linn. (jambolan) on clinical strains of Candida albicans (n = 14), Candida tropicalis (n = 8) and Candida glabrata (n = 8). The minimal inhibitory concentration (MIC) was determined by serial dilution of the extracts (100 to 3125 mg. mL­1) in Sabouraud broth, which were then inoculated with fungical suspensions (106 cells.mL­1) and incubated at 37 °C / 24 hours. After the incubation period, the assays of theprevious test which showed no growth in broth were planted in Sabouraud agar and incubated at 37 °C / 48 hours to determine the Minimal Fungicidal Concentration (MFC). For most strains studied,the MIC of the extract of Rosmarinus officinalis Linn. was similar to the extract of Syzygium cumini Linn., corresponding to 25 mg.mL­1 for C. albicans, 25 mg.mL­1 for C. glabrata and 12.5 mg.mL­1 for C. tropicalis. The MFC of extract of Rosmarinus officinalis Linn. and Syzygium cumini Linn. was, respectively, 25 and 50 mg.mL?1 for C. albicans, 50 mg.mL­1 for C. glabrata and 25 mg.mL­1 for C. tropicalis. It concluded that the extracts of glycolics Rosmarinus officinalis Linn. and Syzygiumcumini Linn. showed potential antifungal for all strains of Candida studied, and the strains of C. tropicalis shown to be more sensitive to extracts in relation to C. albicans and C. glabrata.