A utilização de implantes osseointegráveis e componentes protéticos tornaram-se recursos muito viáveis à resolução de casos simples e complexos na odontologia reabilitadora. No entanto, a junção implante componente pode apresentar problemas, tais como a presença de um microgap entre essas partes constituintes. Assim, vários materiais tem sido testados na tentativa de obstruir esse espaço, com resultados controversos. O objetivo deste estudo foi avaliar in vitro o comportamento de um adesivo anaeróbico (Loctite® 510, Henkel Ltda) monocomponente, de alta resistência e inerte, na vedação do microgap impedindo a passagem bacteriana do meio externo para o interno do conjunto. Foram utilizados 90 implantes de conexão externa hexagonal (n = 30), conexão interna hexagonal (n = 30) e conexão interna cônica (n = 30), divididos em Grupo Controle (n = 45) e Grupo Teste (n = 45). Os implantes foram abertos em fluxo laminar e cada unidade recebeu 3l de BHI estéril internamente. Sobre cada unidade era parafusado um componente protético especifico para cada marca e com torques recomendados pelos fabricantes com torquímetro digital. Os conjuntos Teste receberam ainda uma fina camada de adesivo que era aplicada com microbrush entre as partes; e todas as unidades dos grupos Controle e Teste foram vedados com material obturador provisório na sua porção mais coronal. Cada conjunto foi então imerso em 75 l de Enterococcus faecalis (ATCC 29212) em minitubos até o limite entre a junção implante/componente protético. Todas as amostras foram incubadas em estufa bacteriológica por 7, 14 e 28 dias a 37oC antes de serem reabertas. Após o período proposto, o conteúdo interno dos implantes foi coletado com cones de papel estéreis, diluído e semeado em placas de Petri, incubadas por 48 horas. Houve diferença significante entre o grupo teste e controle no grupo de conexão externa hexagonal, em todos os tempos (Teste de Fischer e Qui-quadrado, p 0.05). O adesivo anaeróbico testado funciona como barreira, não permitindo a migração de bactérias para o meio interno do conjunto implante/componente protético. / The use of dental implants and prosthetic components have become very feasible resources to solve simple and complex cases in rehabilitation dentistry. However, the implant component junction may present problems, such as the presence of a microgap between these components parts.Therefore, several materials have been tested in an attempt to obstruct this space, with controversial results. The objective of this study was to evaluate in vitro the behavior of an anaerobic monocomponent adhesive (Loctite® 510, Henkel Ltda), high resistance and inert characteristics, in the microgap seal preventing bacterial passage from the external side to the inner side of the assembly. A total of 90 implants were used, with hexagonal external connection (n = 30), internal hexagonal connection (n = 30) and internal conical connection (n = 30) divided into Control Group (n = 45). Implants were opened in laminar flow cabinet and each unit received 3l of sterile BHI internally. On each unit a specific prosthetic component was screwed in for each brand and with torques recommended by the manufacturers with digital torque wrench. The sets of Test also received a thin layer of adhesive that was applied with microbrush between the parts; and all units of the Control and Test groups were sealed with provisional obturator material in their most coronal portion. Each set was immersed in 75 l of Enterococcus faecalis (ATCC - 29212) in mini-tubes to the limit between the implant / prosthetic component junction. All samples were incubated in a bacteriological incubator for 7, 14 and 28 days at 37oC before being reopened. After the proposed period, the internal contents of the implants were collected with sterile paper cones, diluted and seeded in Petri dishes, incubated for 48 hours. There was a significant difference between the test and control groups in the hexagonal external connection group at all times (Fischer and Chi-square test, p 0.05). The anaerobic adhesive tested works as a barrier, not allowing the migration of bacteria into the internal environment of the implant / prosthetic component assembly.

O objetivo do presente estudo foi avaliar o efeito antibacteriano do laser diodo com diferentes comprimentos de onda em blocos de dentina infectados com Enterococcus faecalis, por meio de análise microbiológica com espectrofotometria e alterações ultraestruturais por meio de microscópio eletrônico de varredura. Treze dentes unirradiculares foram seccionados de forma a obter 100 blocos de dentina intrarradicular. Inicialmente, os blocos foram imersos por 5 minutos em EDTA 17% e em seguida lavados por 5 minutos com água destilada, e então autoclavados por 30 minutos a 120&deg;C. As amostras de dentina foram inoculadas com 1mL de suspensão de E. faecalis em 5mL de BHI (Brain Heart Infusion) e incubadas a 37&deg;C por cinco dias. Após a contaminação, os espécimes foram distribuídos em dez grupos (n=10) de acordo com tratamento de superfície: GI - 5 mL NaOCl 2,5%, GII - 5 mL NaOCl 2,5% + diodo 808nm, GIII - 5 mL NaOCl 2,5% + diodo 970nm, GIV - diodo 808nm, GV - diodo 970nm, GVI - CHX 2%, GVII - CHX 2% + diodo 808nm, GVIII - CHX 2% + diodo 970nm, GIX - controle positivo e GX controle negativo. O crescimento bacteriano foi analisado pela turbidez e densidade óptica do meio de cultura por espectrofotometria (nm). Em seguida, os espécimes foram preparados para análise das alterações ultraestruturais da superfície dentinária em MEV. Os dados foram submetidos ao teste ANOVA um fator e evidenciaram que o GI (77,5 ± 12,1), GII (72,5 ± 12,2), GIII (68,7 ± 8,7), GV (68,3 ± 8,7), GVI (62,0 ± 5,5) e GVII (67,5 ± 3,3) foram semelhantes entre si e diferente estatisticamente dos grupos GIV (58,8 ± 25,0), GVIII (59,2 ± 4,0) e grupos controles (p<0,05). A análise em MEV evidenciou uma matriz orgânica amorfa e derretimento da dentina intertubular quando submetidos à irradiação do laser diodo 970nm, e erosão da dentina intertubular quando irradiada com laser 808nm, sendo que ao associar NaOCl 2,5% ao laser com diferentes comprimentos de onda, observou-se maior erosão intertubular. Conclui-se que todos os protocolos terapêuticos foram capazes de reduzir o contingente bacteriano dos blocos de dentina e ao associar o laser diodo e soluções não houve melhora significativa na redução do contingente bacteriano. / The objective of this study was to evaluate the disinfection degree of dentin blocks contaminated by Enterococcus faecalis caused by different diode laser wavelengths through microbiological analysis with spectrophotometry and ultrastructural alterations by scanning electron microscope. Thirteen uniradicular teeth were sectioned into 100 dentin Intraradicular blocks. Initially, the blocks were immersed for 5 minutes in 17% EDTA and then washed for 5 minutes with distilled water, and then esterilized for 30 minutes at 120&deg;C. The dentin samples were inoculated with 1mL of E. faecalis suspension in 5mL BHI (Brain Heart Infusion) and incubated at 37&deg;C for five days. After contamination, the specimens were distributed into ten groups (n = 10) according to surface treatment: GI - 5 mL NaOCl 2.5%, GII - 5 mL NaOCl 2.5% + diode 808nm, GIII - 5 mL NaOCl 2.5% + diode 970nm, GIV - diode 808nm, GV - diode 970nm, GVI - CHX 2%, GVII - CHX 2% + diode 808nm, GVIII - CHX 2% + diode 970nm, GIX - positive control and GX - Negative control. Bacterial growth was analyzed by turbidity and optical density of the culture medium by spectrophotometry (nm). Afterwards, the specimens were processed for analysis of the ultrastructural changes of the dentin surface in SEM. The data was subject to the One-way ANOVA test and showed that GI (77,5 ± 12,1), GII (72,5 ± 12,2), GIII (68,7 ± 8,7), GV (68,3 ± 8,7) and GVII (67,5 ± 3,3) were statistically similar and statistically different from GIV (58,8 ± 25,0), GVIII (59,2 ± 4,0) and control groups (p <0.05). SEM analysis showed a modified organic matrix layer with an amorphous, intertubular dentin melting when dentin samples were irradiated with 970nm diode laser, erosion of the intertubular dentin in blocks submitted to 808nm diode laser, and a increased erosion of the intertubular dentin when associating NaOCl 2,5% to the laser with different wavelengths. All the therapeutic protocols were able to reduce the bacterial contingent in dentin blocks with the association of laser diode and solutions did not significantly improve the reduction of the bacterial contingent.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-04-01T14:52:45Z No. of bitstreams: 1 cristianeferreiraalfenas.pdf: 2237269 bytes, checksum: de6cc845b64194029dea071db9814d80 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T03:17:20Z (GMT) No. of bitstreams: 1 cristianeferreiraalfenas.pdf: 2237269 bytes, checksum: de6cc845b64194029dea071db9814d80 (MD5) / Made available in DSpace on 2016-04-24T03:17:20Z (GMT). No. of bitstreams: 1 cristianeferreiraalfenas.pdf: 2237269 bytes, checksum: de6cc845b64194029dea071db9814d80 (MD5) Previous issue date: 2012-03-22 / O propósito do presente estudo foi avaliar, in vitro, a atividade antimicrobiana da Terapia Fotodinâmica (PDT) no sistema de canais radiculares, utilizando diferentes concentrações do fotossensibilizante azul de toluidina e doses do laser, sobre biofilme de Enterococcus faecalis, ATCC 51299. Foram utilizados 42 dentes extraídos de humanos, unirradiculares e os canais foram devidamente preparados, instrumentados pela técnica de instrumentação rotatória. Os dentes foram autoclavados e os canais inoculados com uma suspensão conhecida de Enterococcus faecalis foram incubados por 21 dias. Os espécimes submetidos à PDT, utilizando combinações com diferentes concentrações do fotossensibilizante azul de toluidina (TBO) (0.5, 5 e 10μg/ml) e tempos de irradiação (60, 120, 300 e 600s) equivalentes a doses de energia 6, 12, 30 e 60J, utilizando uma fibra óptica intracanal e irradiação com o laser de diodo (AsGaAl) a 100mW. Os controles, positivo e negativo, não receberam nenhum tipo de tratamento. Amostras do conteúdo intracanal foram coletadas com cone de papel esterilizado, antes e após os respectivos tratamentos e submetidos à cultura contendo ágar BHI. Para determinar o número de unidades formadoras de colônias por mL (UFC/mL). Os dados obtidos na análise microbiológica (UFC/mL) foram analisados por meio da análise de variância e teste de Tukey. E para confirmar a formação de biofilme, dois espécimes de cada grupo foram selecionados e analisados ao microscópio eletrônico de varredura (MEV). As combinações de TBO 0.5μg/ml e 600s e 5μg/ml e 10μg/ml em todos os tempos de irradiação testados resultaram em significativa redução dos micro-organismos, sendo que a combinação TBO 5μg/ml e 600s apresentou significantemente a maior porcentagem de redução. Foi possível concluir que a utilização da PDT com o fotossensibilizante TBO e irradiação com laser de baixa potência apresenta ação antibacteriana significativa sobre biofilme de Enterococcus faecalis, sendo uma terapia promissora frente aos micro-organismos persistentes ao tratamento endodôntico convencional. / The purpose of this study was to evaluate in vitro antimicrobial activity of Photodynamic Therapy (PDT) in the root canal system, using different concentrations of photosensitizer toluidine blue (TBO) and laser doses on biofilms of Enterococcus faecalis, ATCC 51299. Used 42 extracted human teeth, single-rooted and the canals prepared to rotary instrumentation. The teeth were autoclaved and canals inoculated with a suspension Enterococcus faecalis in brain heart infusion and were incubated for 21 days. The specimens were subjected to PDT using combinations with different concentrations of the photosensitizer TBO (0.5, 5 and 10μg/ml) and irradiation times (60, 120, 300 and 600s) equivalent to doses of energy 6, 12, 30 and 60J, using an optical fiber intracanal and irradiation with diode laser (GaAlAs) to 100mW. The controls groups no treatment. Before and after the respective treatments the canal contents were sampled with sterilized paper points, the sample was dispersed in transport medium, serially diluted and culture on blood agar to determine the number of colony forming units per mL (CFU / mL). The data obtained in the microbiological analysis (CFU / mL) were analyzed by analysis of variance and Tukey test. And to confirm biofilm formation, two specimens of each group were selected and analyzed by scanning electron microscopy (SEM). Combinations of TBO 0.5μg/ml and 600s and TBO 5μg/ml, 10μg/ml and in all irradiation times tested resulted in significant reduction of micro-organisms but the combination TBO 5μg/ml and 600s showed significantly higher percentage of reduction. It was concluded that the use of PDT with the photosensitizer TBO and laser irradiation low power presents significant antibacterial action on biofilm of Enterococcus faecalis, is a promising therapy in the face of persistent micro-organisms to conventional endodontic treatment.

Alexandre Augusto ZaiaOrientador: / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-22T16:52:01Z (GMT). No. of bitstreams: 1 Suzuki_ClaudiaLealSampaio_M.pdf: 1692911 bytes, checksum: 11c9ab9ff10af76a78f2989485f0ed25 (MD5) Previous issue date: 2013 / Resumo: O objetivo do estudo foi avaliar se as bactérias Streptococcus mutans, Enterococcus faecalis e Porphyromonas gingivalis alteram a secreção de colágeno tipo ? por fibroblastos 3T3 e odontoblastos MDPC-23 em cultura celular; e, havendo alteração, se é dependente do contato célula/bactéria ou apenas dos subprodutos bacterianos. Fibroblastos 3T3 e odontoblastos MDPC-23 foram cultivados e incubados com as bactérias Streptococcus mutans, Enterococcus faecalis e Porphyromonas gingivalis (MOI 1:1) nos períodos de 2, 4 e 8 horas. As bactérias ficaram em contato direto com as células, e em contato indireto através do uso de inserts de 0.4?m. A produção de colágeno tipo I secretado pelas células foi quantificada pelo Ensaio de Imunoabsorbância Ligado à Enzima (Enzyme-Linked Immunosorbent Assay, ELISA), e sua organização estrutural (birrefringência) foi visualizada em microscopia de polarização após coloração com picrosirus. Assim, pode-se concluir que a infecção com S. mutans, E. faecalis e P. gingivalis estimularam um aumento nos níveis de colágeno tipo I nos períodos de 2 e 4 horas em cultura de odontoblastos MDCP-23, e um aumento progressivo nos níveis de colágeno tipo I entre 2 e 8 horas em cultura de fibroblastos 3T3. Também se observou que o estímulo para o aumento na produção de colágeno se deve a ação dos subprodutos liberados pelas bactérias e não pelo contato célula/bactéria / Abstract: The aim of the study was to evaluate whether the bacteria Streptococcus mutans, Enterococcus faecalis and Porphyromonas gingivalis alter the secretion of type I collagen by 3T3 fibroblasts and MDPC-23 odontoblast-like cells in cell culture, and, with change, if it is dependent on the contact cell/bacteria or only bacterial by-products. 3T3 fibroblasts and MDPC-23 odontoblast-like cells were cultured and incubated with the bacteria S. mutans, E. faecalis and P. gingivalis (MOI 1:1) for the periods of 2, 4 and 8 hours. The bacteria were in direct contact with the cells, and indirect contact through the use of inserts 0.4 ?m. The production of type I collagen secreted by cells was quantified by Enzyme-Linked Immunosorbent Assay (ELISA), and its structural organization (birefringence) was visualized in polarized light microscopy after staining with picrosirus. Thus, it can be concluded that infection with S. mutans, E. faecalis and P. gingivalis stimulated an increase in the levels of type I collagen in periods 2 and 4 hours in cultured MDPC-23 odontoblast-like cells, and a progressive increase in the levels of type I collagen between 2 and 8 hours in cultured 3T3 fibroblasts. It was noted that the stimulus for the increase in collagen production is due to the action of the by-products released by bacteria and not by contact cell/bacteria / Mestrado / Endodontia / Mestra em Clínica Odontológica

Objetivo: Avaliar, in vitro, a efetividade da terapia fotodinâmica, com e sem o uso da fibra óptica intracanal diante de diferentes períodos de irradiação, na redução de Enterococcus faecalis em canais radiculares. Método: Foram utilizados sessenta dentes unirradiculares humanos, preparados e divididos em seis grupos (n=10), de acordo com o tratamento a ser realizado: G1, azul de metileno 0,01% (t=5min) e irradiação com laser de diodo por meio de fibra óptica intracanal (P=90mW), por um minuto e trinta segundos; G2, azul de metileno 0,01% (t=5min) e irradiação do mesmo modo que o G1, por três minutos; G3, azul de metileno 0,01% (t=5min) e irradiação sem fibra óptica intracanal (P=100mW), por um minuto e trinta segundos; G4, azul de metileno 0,01% (t=5min) e irradiação do mesmo modo que o G3 por três minutos; G5, hipoclorito de sódio 1% (t=15min); e G6, sem tratamento. Todas as amostras foram coletadas por meio de cones de papel esterilizados, antes e após os respectivos tratamentos e submetidas à cultura em placas de Petri contendo ágar BHI, em duplicata. Após 24 horas de incubação, promoveu-se a contagem das unidades formadoras de colônia (UFC/mL). Resultados: A aplicação de todos os tratamentos resultou em significativa redução dos microrganismos, apresentando-se em ordem decrescente de redução G5>G2>G4>G1>G3. Observou-se diferença estatisticamente significante entre os grupos G1 X G5 e G3 X G5. Conclusões: Os parâmetros utilizados nos diferentes grupos proporcionaram reduções intracanais significativas e semelhantes de E. faecalis; a utilização de potências máximas permitiu a redução do tempo de irradiação sem interferir a ação antimicrobiana; e o emprego da fibra óptica intracanal não influenciou de forma significativa nos resultados quando comparado ao uso da peça de mão. / Objective: To evaluate in vitro the effectiveness of photodynamic therapy on the reduction of Enterococcus faecalis in root canals, with and without use of the optical fiber into the canal in front of different period of time irradiation. Method: Sixty human single-root teeth were prepared and divided into six groups, in accordance with the treatment: G1, methylene blue 0,01% (t=5min) and irradiation by diode laser with intracanal optic fiber (P=90mW) for one minute and thirty seconds; G2, methylene blue 0,01% (t=5min) and irradiation the same way that G1, for three minutes; G3, methylene blue 0,01% (t=5min) and irradiation without optic fiber (P=100mW) for one minute and thirty seconds; G4, methylene blue 0,01% (t=5min) and irradiation the same way that G3 for three minutes; G5, 1% sodium hypochlorite (t=15min); and G6, without treatment. All the samples were collected by sterilized paper points, before and after respective treatments, and submitted to microbiological culture plated on BHI ágar duplicated. After 24 hours of incubation, it was performed the evaluation of colony-forming units (CFU/mL). Results: The application of all treatments resulted in significant reduction of microorganismsviability, showing in reductions decreasing order: G5>G2>G4>G1>G3. Significant statistical differences were observed among the groups G1 X G5 and G3 X G5. Conclusions: All the parameters used in the groups afforded significant and similar numerical reduction of E. faecalis; the use the maxim powers allowed a reduction of the irradiation time without compromise the antimicrobial effect; and the use of the intracanal optic fiber didnt influence the results when compared with the use of hand peace.

Orientador: Carlos Henrique Ribeiro Camargo / Coorientadora: Marcia Carneiro Valera Garakis / Banca: Cláudio Antonio Talge Carvalho / Banca: Flaviana Bombarda de Andrade / Resumo: O objetivo deste estudo foi avaliar, in vitro, a capacidade antimicrobiana da N-Acetilcisteína (NAC) e da terapia fotodinâmica (PDT) utilizando LASER diodo (LD) de baixa intensidade, sobre o Enterococcus faecalis, comparados ao uso do hidróxido de cálcio [Ca(OH)2] como medicação intracanal. Oitenta dentes humanos extraídos tiveram o diâmetro dos canais radiculares padronizados por meio do preparo com lima K#30. As raízes foram contaminadas com E. faecalis por 21 dias e divididas em cinco grupos de acordo com a medicação intracanal e/ou tratamento antimicrobiano a ser utilizada: 1) PDT+NAC; 2) NAC; 3) PDT; 4) Ca(OH)2 e 5) Solução salina. Sendo que 50 dentes foram avaliados por cultura microbiológica (UFC/mL), 10 por microscopia eletrônica de varredura (MEV) e 20 por microscopia confocal de varredura a LASER (CLSM). Para UFC/mL foram feitas 3 coletas do conteúdo o canal radicular: a) após 21 dias de contaminação (coleta de confirmação - Sc); b) após PBM (S1); c) após 14 dias com as medicações intracanais (S2). UFC/mL não mostrou diferença estatística entre os grupos de PDT+NAC, NAC e Ca(OH)2, porém foram significantemente diferentes dos grupos da PDT, e solução salina. A análise ilustrativa por MEV mostrou resultados semelhantes à análise microbiológica (UFC/mL). No CLSM, todos os grupos avaliados foram efetivos contra E. faecalis, com a diferençando significantemente do grupo controle. Concluímos que NAC pode eliminar E. faecalis com ou sem PDT, sendo considerado como medicaçã... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this study was to evaluate in vitro the antimicrobial capacity of N-Acetylcysteine (NAC) and photodynamic therapy (PDT) using low intensity LASER diode (LD) on Enterococcus faecalis, compared to the use of calcium hydroxide Ca(OH)2, as intracanal medication. Eighty extracted human teeth had their root canal diameters steardized by preparation with K 30 file. The roots were contaminated with E. faecalis for 21 days and divided into five groups according to the intracanal medication and/or antimicrobial treatment to be used. 1) PDT + NAC; 2) NAC; 3) PDT; 4) Ca(OH)2; 5) Saline solution. Fifty teeth were evaluated by microbiological culture (CFU/mL), 10 by scanning electron microscopy (SEM), and 20 by confocal LASER scanning microscopy (CLSM). The root canal was collected 3 times a) after 21 days of contamination (confirmation collection) (Sc); b) after biomechanical preparation S1; c) after 14 days with intracanal medications. CFU/mL showed no statistical difference between the PDT+NAC, NAC e Ca(OH)2 groups, but were significantly different from the PDT groups, and saline. The illustrative SEM analysis showed similar results to the analysis (CFU / mL). In CLSM, all evaluated groups were effective against E. faecalis, with a significant difference with the control group. We conclude that NAC can eliminate E. faecalis with or without PDT, being considered as a complementary medication in clinical practice / Mestre

Philosophiae Doctor - PhD / The Black soldier fly (BSF) is an environmentally friendly and sustainable insect utilised in the decomposition of organic waste. This is due to its voracious consumption capability, disruptive functions and economic importance. The sustained global increase in commercial BSF farming has resulted in an expanded waste generation from its carcases to which beneficial uses ought to be developed. This study focused on the beneficial use of the generated waste by extracting chitosan from waste pupae and commercially reared BSF adult carcases. The study also considered the conversion of the extracted chitosan to nanofibres and nanoparticles for application in adsorption of inorganic Pb2+ or Cd2+ and antimicrobial studies, respectively. To achieve the aim of this study, the optimal extraction conditions of chitin and chitosan from both pupal exuviae and adult BSF waste materials were attained after a series of experiments. The extraction process involved three stages which were demineralisation, deproteination and deacetylation. The extracted adult and pupal chitin and chitosan were characterised using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction studies (XRD), high resolution scanning electron microscopy (HRSEM) and solid-state carbon nuclear magnetic resonance spectroscopy (13C NMR). Additionally, the adult (ACH20_9) and pupal (PCH21_9) chitosan samples, due to their solubility, were further characterised to determine their molecular weight, fat and water binding capacities, solubility and ash contents. / 2021-09-30

Enterococcus faecalis est une bactérie commensale du microbiote intestinal humain. Inoffensive chez l'homme sain, E. faecalis est aussi un pathogène opportuniste. En conditions de dysbiose post-antibiotique, E. faecalis peut devenir une espèce dominante, traverser la barrière intestinale avant de disséminer. E. faecalis se classe désormais comme la troisième cause d'infections nosocomiales dans le monde. La pathogénie de E. faecalis est un processus multifactoriel dont les mécanismes cellulaires de son interaction avec l'hôte sont encore mal compris. À l'aide de modèles cellulaires d'infection et de modèles in vivo, nous avons entrepris de caractériser le rôle du facteur de virulence ElrA pendant l'infection cellulaire.Notre objectif était également de déterminer si FHL2, un partenaire eucaryote de ElrA, était impliqué dans l'infection par E. faecalis et de determiner l'impact de l'interaction ElrA-FHL2. Nous avons démontré que ElrA agit comme une cape d'invisibilité permettant à E. faecalis de ne pas être détecté par des macrophages. Nous avons également montré que FHL2 est impliqué dans la défense de l’hôte contre l'infection par E. faecalis, mais ce rôle implique partiellement ElrA. Parallèlement, nous avons montré pour la première fois que E. faecalis est capable de se multiplier dans les hepatocytes. En conclusion, ce travail apporte de nouvelles perspectives sur les interactions de E. faecalis avec son hôte. / Enterococcus faecalis is a core member of the human gut microbiota. Harmless for healthy humans, it is able to cause disease in susceptible patients under antibiotic-induced microbiota alteration. Nowadays, E. faecalis ranks as the third cause of nosocomial infections worldwide. E. faecalis pathogenicity is a multifactorial process but the cellular mechanisms of its interaction with the host remain poorly understood. Using cellular models of infection and in vivo models, we aimed to characterize the role of the virulence factor ElrA during cellular infection. Our goal was also to determine if FHL2, an ElrA eukaryotic partner, was implicated in E. faecalis infection and the impact of ElrA-FHL2 interaction. We have demonstrated that ElrA acts as an invisibility cloak allowing E. faecalis to avoid macrophage recognition. Also, we have shown that FHL2 is implicated in the defense against E. faecalis infection, involving partially ElrA. In parallel, we showed that intracellular replication of E. faecalis in hepatic cells. Altogether, our work provides new insights in E. faecalis interactions with the host cell.

Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: Microbial biofilms have been shown to be a cause of persistent endodontic infections. It is more resistant than planktonic bacteria to host immune defenses and antimicrobials. Studies indicate that photodynamic light therapy (PDT), which involves using light at specific wavelengths, has a potent antibacterial effect on bacterial biofilm. PDT is an antimicrobial strategy that involves the use of a nontoxic photosensitizer (PS) along with a light source. The excited PS reacts with molecular oxygen to produce highly reactive oxygen species, which induce injury or death to microorganisms. PSs have a high degree of selectivity for inhibiting microorganisms without negatively affecting host mammalian cells. PDT has been suggested as an adjuvant to conventional endodontic treatment. Studies at IUSD have shown that blue light at 380 nm to 440 nm has the ability to inactivate Streptococcus mutans biofilm without any exogenous PS. Objective: The objective of this study was to determine the effectiveness of blue light at 380 nm to 440 nm to reduce adherence of Enterococcus faecalis biofilm after NaOCl irrigation at various concentrations. Materials and Methods: E. faecalis biofilm was established for 72 hours in 96- well flat-bottom microtiter plates using Tryptic Soy Broth supplemented with 1.0-percent sucrose (TSBS). Biofilm was irradiated with blue light for 5 minutes before exposure to various concentrations of NaOCl for 30 seconds. A crystal violet biofilm assay was used to determine relative density of the biofilm. Data were analyzed with two-way ANOVA and Sidak-adjusted multiple comparisons using a 5.0-percent significance level. Null Hypothesis: Blue light and NaOCl will not have an effect against E. faecalis biofilm adherence. Results: Overall, there was a significant effect (p < 0.05) for NaOCl and a significant effect for blue light. The effects of the combination of NaOCl and blue light were also significant. Conclusion: We reject the null hypothesis and accept the alternative hypothesis that blue light when used in conjunction with NaOCl will reduce adherence of E. faecalis biofilm.

Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: One of the main objectives of endodontic therapy is to reduce microbes and remove inflamed pulpal tissue within the root canal system (RCS). This is accomplished through chemomechanical debridement of the RCS using hand and rotary instrumentation along with an antimicrobial irrigant. Today, the most commonly used irrigant is sodium hypochlorite (NaOCl), often at concentrations toxic to human cells. The use of ozone as an endodontic irrigant is a novel technique that has been proven to be antimicrobial against several microorganisms. However, independent research is lacking on ozone’s efficacy against an established endodontic biofilm. If ozone’s efficacy against biofilms is confirmed, the use of toxic and potentially dangerous sodium hypochlorite could be replaced in some clinical situations (i.e., regeneration, immature teeth, resorption) with a safer and effective alternative. Objective: The aim of the current study was to evaluate the anti-biofilm activity of different concentrations of ozonated water compared to various concentrations of NaOCl against an established endodontic biofilm of Enterococcus faecalis in root canal treated teeth in vitro. Materials and Methods: The crowns of similarly sized, maxillary anterior teeth were removed, and the roots cut to a standard length (12 mm). All root canals were instrumented to a standard size. Specimens were sterilized and then inoculated with E. faecalis, which were allowed to grow for two weeks to form an established biofilm. There were six treatment groups: 1) 6% NaOCl; 2) 1.5% NaOCl; 3) 16µg/mL ozonated water; 4) 25µg/mL ozonated water; 5) 50µg/mL ozonated water, and 6) saline. Following treatment, samples were collected, plated, and incubated for two days. The number of CFU/mL were determined, and samples visualized using confocal imaging. The effect of treatment group on bacterial counts was made using one-way ANOVA followed by pair-wise comparisons. Null Hypothesis: Endodontically treated teeth irrigated with ozonated water will not demonstrate a statistically significant decrease in the E. faecalis biofilm compared to those treated with sodium hypochlorite Results: CFUs were converted to log10 and compared using Fisher’s Exact tests or one-way ANOVA followed by pair-wise tests. In all observations utilizing NaOCl irrigation, no colonies formed following treatment. The two NaOCl groups, with 0 CFU/mL, were significantly different than the other four groups (p=0.009). Saline showed a trend towards higher CFU/mL than 50 µg/ml O3 (p=0.068). None of the other comparisons approached statistical significance (p=0.453 25 µg/ml O3, p=0.606 16 µg/ml O3, p=0.999 25 µg/ml O3 vs 50 µg/ml O3, p=0.990 16 µg/ml O3 vs 50 µg/ml O3, p=1.000 16 µg/ml O3 vs 25 µg/ml O3). Confocal imaging helped illustrate effects of irrigation and confirm CFU findings. Conclusion: The results of this study failed to reject the null hypothesis. There was a statistically significant difference in the E. faecalis biofilm remaining in the groups treated with ozonated water compared to those treated with NaOCl. However, there was a trend towards higher CFU/mL in the saline group compared to the 50µg/mL ozonated water group. According to this finding, future studies should evaluate the effects of higher concentrations of ozonated water against an established E. faecalis biofilm. In addition, other follow-up studies might include ozonated water’s effect on human cells, such as the stem cells of the apical papilla that are so critical to the success of regenerative endodontic procedures. Due to university and laboratory closures caused by the COVID-19 pandemic, this project was stopped short and an insufficient sample size did not allow for proper statistical power. Additional occasions should be run upon the university’s re-opening to allow for proper statistical power.