Recent Updates on Microbial Biofilms in Periodontitis: An Analysis of In Vitro Biofilm Models.

The development of oral biofilm models has been extremely important to study the specific role of most microbial species at the early stages of periodontitis. The current knowledge on monospecies or multispecies biofilms originates mainly from the observation of in vitro dynamic or static biofilm model systems, which were engineered to mimic clinical oral conditions. In the last few decades, mounting evidence has confirmed that biofilms are the major form of bacterial lifestyle, and more importantly, that microorganisms dwelling in sessile mixed-species aggregates display completely different phenotypes and physiological characteristics than when living in planktonic pure cultures. Interspecies interactions within these communities, mediated by chemical communication systems, have been shown to affect biofilm physiology and increase antimicrobial resistance by up to 1000 fold. These aspects reinforce the importance of developing multispecies biofilm models to better understand and control biofilms. Literature reports demonstrate that while monospecies models are still most commonly used in caries research, authors have used different multispecies models to study periodontal diseases. Periodontitis is a polymicrobial biofilm-dependent disease mainly associated with Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola. Interestingly, these species hardly adhere to substrates commonly used for biofilm formation, which makes multispecies models essential for an accurate analysis of periodontitis-related biofilms. The multispecies models currently available are generally composed of 6-10 species, but a more recent 34-species model was developed to better examine the dynamics within oral biofilms. The complexity of such polymicrobial biofilm models mimics more consistently the oral microbiome and different aspects of the oral environment. Collectively, the evidence on multispecies biofilm models described herein may support future studies on the use of antimicrobials for biofilm control as well as provide research opportunities to expand the current knowledge on interspecies interactions. The present manuscript reviews the most recent updates on in vitro biofilm model systems for periodontitis.

Comparison of results from two different leakage models to evaluate the apical sealing of endodontic materials

Introduction: The methods used to evaluate the apical sealing of root canal filling materials have some limitations and great variability of results can be observed. Aim: The aim of this study was to compare, in an ex vivo apexification model, the results from bacterial and glucose leakage tests, which were applied in mineral trioxide aggregate (MTA) apical plugs. Materials and Methods: Sixty root segments (12mm) were randomly divided into 2 experimental groups (n=30): G1) MTA; G2) MTA + phosphate-buffered saline intracanal. Half of the specimens in each group were submitted to bacterial leakage test with E. faecalis for 70 days. The other half was submitted to the glucose leakage test under pressure (103KPa) for 60 min. The results from the two tests were compared based on the number of specimens presenting leakage. Data were analyzed by Fisher's test (p < 0.05). Results: There was no significant difference between tests for both groups analyzed (p > 0.05).Conclusion: The results of the present ex vivo study demonstrated that there was no difference between glucose and bacteria leakage evaluation methods, within the parameters of the present study and regardless

Strategies to Reduce Biofilm Formation in PEEK Materials Applied to Implant Dentistry-A Comprehensive Review.

Polyether-ether-ketone (PEEK) has emerged in Implant Dentistry with a series of short-time applications and as a promising material to substitute definitive dental implants. Several strategies have been investigated to diminish biofilm formation on the PEEK surface aiming to decrease the possibility of related infections. Therefore, a comprehensive review was carried out in order to compare PEEK with materials widely used nowadays in Implant Dentistry, such as titanium and zirconia, placing emphasis on studies investigating its ability to grant or prevent biofilm formation. Most studies failed to reveal significant antimicrobial activity in pure PEEK, while several studies described new strategies to reduce biofilm formation and bacterial colonization on this material. Those include the PEEK sulfonation process, incorporation of therapeutic and bioactive agents in PEEK matrix or on PEEK surface, PEEK coatings and incorporation of reinforcement agents, in order to produce nanocomposites or blends. The two most analyzed surface properties were contact angle and roughness, while the most studied bacteria were Escherichia coli and Staphylococcus aureus. Despite PEEK's susceptibility to biofilm formation, a great number of strategies discussed in this study were able to improve its antibiofilm and antimicrobial properties.

Effect of γ-lactones and γ-lactams compounds on Streptococcus mutans biofilms.

Considering oral diseases, antibiofilm compounds can decrease the accumulation of pathogenic species such as Streptococcus mutans at micro-areas of teeth, dental restorations or implant-supported prostheses. OBJECTIVE: To assess the effect of thirteen different novel lactam-based compounds on the inhibition of S. mutans biofilm formation. MATERIAL AND METHODS: We synthesized compounds based on γ-lactones analogues from rubrolides by a mucochloric acid process and converted them into their corresponding γ-hydroxy-γ-lactams by a reaction with isobutylamine and propylamine. Compounds concentrations ranging from 0.17 up to 87.5 µg mL-1 were tested against S. mutans. We diluted the exponential cultures in TSB and incubated them (37°C) in the presence of different γ-lactones or γ-lactams dilutions. Afterwards, we measured the planktonic growth by optical density at 630 nm and therefore assessed the biofilm density by the crystal violet staining method. RESULTS: Twelve compounds were active against biofilm formation, showing no effect on bacterial viability. Only one compound was inactive against both planktonic and biofilm growth. The highest biofilm inhibition (inhibition rate above 60%) was obtained for two compounds while three other compounds revealed an inhibition rate above 40%. CONCLUSIONS: Twelve of the thirteen compounds revealed effective inhibition of S. mutans biofilm formation, with eight of them showing a specific antibiofilm effect.

Effect of γ-lactones and γ-lactams compounds on Streptococcus mutans biofilms

Abstract Considering oral diseases, antibiofilm compounds can decrease the accumulation of pathogenic species such as Streptococcus mutans at micro-areas of teeth, dental restorations or implant-supported prostheses. Objective To assess the effect of thirteen different novel lactam-based compounds on the inhibition of S. mutans biofilm formation. Material and methods We synthesized compounds based on γ-lactones analogues from rubrolides by a mucochloric acid process and converted them into their corresponding γ-hydroxy-γ-lactams by a reaction with isobutylamine and propylamine. Compounds concentrations ranging from 0.17 up to 87.5 μg mL-1 were tested against S. mutans. We diluted the exponential cultures in TSB and incubated them (37°C) in the presence of different γ-lactones or γ-lactams dilutions. Afterwards, we measured the planktonic growth by optical density at 630 nm and therefore assessed the biofilm density by the crystal violet staining method. Results Twelve compounds were active against biofilm formation, showing no effect on bacterial viability. Only one compound was inactive against both planktonic and biofilm growth. The highest biofilm inhibition (inhibition rate above 60%) was obtained for two compounds while three other compounds revealed an inhibition rate above 40%. Conclusions Twelve of the thirteen compounds revealed effective inhibition of S. mutans biofilm formation, with eight of them showing a specific antibiofilm effect.

Pesquisa a serviço da sociedade: área de concentração de Implantodontia do PPGO/UFSC / Scientific research for social benefits: oral Implantology at the PPGO/UFSC

Este manuscrito descreve as atividades desenvolvidas na PPGO/UFSC, concentradas em três linhas de pesquisa: 1) neoformação óssea peri-implantar; 2) engenharia tecidual; e 3) microbiologia aplicada à Implantodontia. Na linha um, diversos métodos analíticos quantitativos e qualitativos (SEM, AFM, FTIR, OCP, EIS, FEG-SEM) têm sido usados para investigação de diferentes intensidades de corrente elétrica na superfície do Ti-cp e Ti-6Al-4V, quando imersos em meios fisiológicos simulados, na adsorção de proteínas, proliferação celular com fibroblastos, queratinócitos e osteoblastos. Na linha dois, o desenvolvimento in vitro de um arcabouço poroso de PLGA e cerâmica bifásica, incorporado com sinvastatina, sera testado in vivo na resposta de fibroblastos gengivais provenientes de cultura primaria, em meio de cultura com plasma rico em plaquetas (PRP), depositado sobre matriz dérmica acelular e matriz de celulose bacteriana (BC). A linha três concentra a atuação com dois centros internacionais (Belgica e EUA) para a incorporação de compostos antibiofilme em polímeros biocompatíveis, e verificação da eficiência de um método de liberação prolongada de antibióticos incorporados em superfícies nanoestruturadas. Estes projetos devem resultar em melhoria de saúde aos pacientes e no desenvolvimento econômico e social da comunidade.

This paper describes the activities developed at PPGO/UFSC divided into three research lines: 1) peri-implant bone neoformation; 2) tissue engineering, and 3) microbiology applied to implant dentistry. On the first line, several quantitative and qualitative (SEM, AFM, FTIR, OCP, EIS, FEG-SEM) analytical methods have been used to investigate the different electric current intensities on Ti c.p. and Ti6Al4V implant surfaces when immersed into simulated physiological media, protein adsorption, cell proliferation with fibroblasts, keratinocytes, and osteoblasts. On the second line, the in vitro development of a 3D PLGA and biphasic ceramic, simvastatin-incorporated scaffold will be tested in vivo for gingival fibroblast response from primary culture in platelet-rich plasma (PRP) enriched vehicle over an acellular dermal (Sure- Derm) and bacterial cellulose matrix (BC). For line three, two international research centers (Belgium and USA) joined common efforts to incorporate polymer anti-biofi lm compounds and to verify the efficiency of a prolonged release method for antibiotics attached to nanostructured surfaces. All those projects must result in better health conditions and social and economic development of our community.