Estudio del efecto antimicrobiano de diferentes soluciones y extractos de origen natural en un modelo in vitro de biofilm subgingival multiespecies

Las periodontitis son enfermedades multifactoriales, crónicas, de origen inflamatorio, asociadas a un biofilm dental disbiótico, caracterizada por la destrucción progresiva de los tejidos periodontales de suporte. Los biofilms dentales subgingivales se caracterizan por ser comunidades bacterianas, estructuradas en matrices de polisacáridos extracelulares organizados adheridas, en la cavidad oral, a las superficies, en un medio líquido. Los dientes, al no sufrir descamación, permiten el desarrollo de biofilms bacterianos complejos, que pueden incluir varios centenares de especies bacterianas diferentes. Debido a los problemas asociados al uso de antimicrobianos, incluida la creciente preocupación con las resistencias bacterianas frente a antimicrobianos, existe en la actualidad un creciente interés en el estudio de los productos de origen natural para el tratamiento y prevención de diferentes enfermedades, incluidas las enfermedades periodontales. Entre estos productos potencialmente útiles como compuestos antibacterianos alternativos, se encuentran sustancias como los polifenoles y los ácidos grasos. Hoy en día, la evidencia científica que estudia el efecto de dichas sustancias frente a patógenos orales es escasa y la mayoría de la información disponible estudia sus efectos frente a bacterias en estado planctónico o en biofilms mono especie. Así, este trabajo se propone evaluar dichas sustancias en un modelo in vitro de biofilm subgingival multiespecies, previamente validado. Objetivos: Evaluar la capacidad antimicrobiana de los diferentes productos y/o extractos de origen natural analizados en cada uno de los tres estudios que forman parte del presente trabajo, en un modelo in vitro de biofilm subgingival multiespecies..

Diagnóstico e tratamento de mordidas cruzadas unilaterais com aparatologia removível : avaliação de um caso clínico e estudo sobre a prevalência de mordidas

As mordidas cruzadas posteriores são das más oclusões mais prevalentes na dentição primária e mista. Estas manifestam-se mais frequentemente de forma unilateral. Apesar disso, aquando da manipulação da mandíbula, em relação cêntrica observa-se que em grande parte das situações existe um comprometimento bilateral. Dessa forma, o conhecimento das características patognomónicas destes tipos de más oclusões é essencial de forma a se obter um diagnóstico preciso que distinga eficazmente se a afeção é unilateral ou bilateral. Um diagnostico precoce e um plano de tratamento adequado mostra-se de especial importância neste tipo de más oclusões dado que uma intervenção precoce, com a correção de fatores etiológicos e/ou intervenção ativa, pode travar a evolução, melhorar o prognostico ou até mesmo corrigi-la definitivamente. Está também descrito que maxilas desadequadamente estreitas reduzem o espaço para a correta erupção dentária. Além disso, a atividade dos músculos temporal e masséter estão alteradas o que faz com que pacientes com este tipo de patologia sejam mais suscetiveis de desenvolver desordens cranio-mandibulares Nesta dissertação é abordado o diagnostico diferencial e hipóteses de tratamento. É também mostrado um caso clinico de mordida cruzada unilateral tratada com aparatologia removível e um estudo transversal de prevalência de mordidas cruzadas em crianças do agrupamento de escolas de Mundão, Viseu, Portugal.The posterior crossbites are some of the most prevailing malocclusions in primary and mixed dentition. These are more frequently seen in unilateral form. Besides that, when the mandible is manipulated we observe that in most of the situations exists a bilateral compromising. Thereby the knowledge of the pathognomonic features of these types of malocclusions is essential in order to obtain an accurate diagnosis that effectively distinguishes if the affection is unilateral or bilateral. An early diagnosis and an appropriate treatment plan proves to be of special importance in this type of malocclusion since early intervention, with the correction of etiologic factors, and/or active intervention can halt the progress, improve the prognosis or even correct it definitely. It’s also described that inadequately narrow jaws reduce the space for proper tooth eruption. Furthermore, the activity of the masseter and temporalis muscles is altered which means that patients with this type of pathology are more likely to develop craniomandibular disorders. In this dissertation are addressed diagnoses, treatment hypotheses and differentiation between them. It’s also shown a clinical case of unilateral crossbite treated with removable appliances and a cross-sectional study of prevalence of crossbites in children attending the school cluster of Mundão, Viseu, Portugal

Relevance of Biofilm Models in Periodontal Research: From Static to Dynamic Systems

Microbial biofilm modeling has improved in sophistication and scope, although only a limited number of standardized protocols are available. This review presents an example of a biofilm model, along with its evolution and application in studying periodontal and peri-implant diseases. In 2011, the ETEP (Etiology and Therapy of Periodontal and Peri-Implant Diseases) research group at the University Complutense of Madrid developed an in vitro biofilm static model using representative bacteria from the subgingival microbiota, demonstrating a pattern of bacterial colonization and maturation similar to in vivo subgingival biofilms. When the model and its methodology were standardized, the ETEP research group employed the validated in vitro biofilm model for testing in different applications. The evolution of this model is described in this manuscript, from the mere observation of biofilm growth and maturation on static models on hydroxyapatite or titanium discs, to the evaluation of the impact of dental implant surface composition and micro-structure using the dynamic biofilm model. This evolution was based on reproducing the ideal microenvironmental conditions for bacterial growth within a bioreactor and reaching the target surfaces using the fluid dynamics mimicking the salivary flow. The development of this relevant biofilm model has become a powerful tool to study the essential processes that regulate the formation and maturation of these important microbial communities, as well as their behavior when exposed to different antimicrobial compounds

New Evidences of Antibacterial Effects of Cranberry Against Periodontal Pathogens

The worrying rise in antibiotic resistances emphasizes the need to seek new approaches for treating and preventing periodontal diseases. The purpose of this study was to evaluate the antibacterial and anti-biofilm activity of cranberry in a validated in vitro biofilm model. After chemical characterization of a selected phenolic-rich cranberry extract, its values for minimum inhibitory concentration and minimum bactericidal concentration were calculated for the six bacteria forming the biofilm (Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans). Antibacterial activity of the cranberry extract in the formed biofilm was evaluated by assessing the reduction in bacteria viability, using quantitative polymerase chain reaction (qPCR) combined with propidium monoazide (PMA), and by confocal laser scanning microscopy (CLSM), and anti-biofilm activity by studying the inhibition of the incorporation of different bacteria species in biofilms formed in the presence of the cranberry extract, using qPCR and CLSM. In planktonic state, bacteria viability was significantly reduced by cranberry (p 0.05)). Conversely, cranberry significantly (p < 0.001 in all cases) interfered with the incorporation of five of the six bacteria species during the development of 6 h-biofilms, including P. gingivalis, A. actinomycetemcomitans, and F. nucleatum. It was concluded that cranberry had a moderate antibacterial effect against periodontal pathogens in biofilms, but relevant anti-biofilm properties, by affecting bacteria adhesion in the first 6 h of development of biofilms

The Antimicrobial Activity of Curcumin and Xanthohumol on Bacterial Biofilms Developed over Dental Implant Surfaces

In search for natural products with antimicrobial properties for use in the prevention and treatment of peri-implantitis, the purpose of this investigation was to evaluate the antimicrobial activity of curcumin and xanthohumol, using an in vitro multi-species dynamic biofilm model including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of curcumin (5 mM) and xanthohumol (100 μM) extracts, and the respective controls, were evaluated with 72-h biofilms formed over dental implants by their submersion for 60 seconds. The evaluation was assessed by quantitative polymerase chain reaction (qPCR), confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). For the data analysis, comparisons were tested applying ANOVA tests with post-hoc Bonferroni corrections to evaluate the antimicrobial activity of both extracts. With qPCR, statistically significant reductions in bacterial counts were observed for curcumin and xanthohumol, when compared to the negative control. The results with CLSM and SEM were consistent with those reported with qPCR. It was concluded that both curcumin and xanthohumol have demonstrated antimicrobial activity against the six bacterial species included in the dynamic in vitro biofilm model used

Estudio del efecto biocida de un nuevo material inorgánico sobre la formación de un biofilm oral in vitro

Introducción y objetivos: Las enfermedades periodontales tienen una naturaleza inflamatoria e infecciosa. Las bacterias presentes en estas patologías presentan fenotipos distintos de acuerdo con su organización planctónica o en biofilm. El biofilm se forma gracias a la adhesión y a la coagregacion entre microorganismos sobre una superficie. El uso de implantes dentales es una práctica odontológica muy difundida al día de hoy. Una posible línea de investigación para la prevención de las enfermedades periimplantarias seria el estudio de nuevos materiales que fueran capaces de inhibir la formación y el crecimiento del biofilm bacteriano. El objetivo de este trabajo fue comprobar el efecto biocida del recubrimiento de Ecovidrio G3 sobre un modelo de biofilm subgingival in vitro de seis bacterias. Material y métodos: Las cepas bacterianas seleccionadas, Streptococcus oralis (So), Actinomyces naeslundii (An), Veillonella parvula (Vp), Fusobacterium nucleatum (Fn), Aggregatibacter actinomycetemcomitans (Aa) y Porphyromona gingivalis (Pg), se pusieron sobre la superficie de los discos de un material compuesto cerámicocerámico nanocomposite Z10Ce recubierto Ecovidrio G3 (A1) (con efecto biocida) y de los discos control de hidroxiapatita (HA). Se depositaron en una placa de cultivo celular tres discos de cada material, y se cubrieron con 1.5 mL de inóculo con las cepas bacterias seleccionadas. Las placas se incubaron en condiciones de anaerobiosis durante 24, 48 y 72 horas, a 37ºC. Los recuentos bacterianos se realizaron en placas de Agar Sangre suplementado y medio Dentaid-1. El biofilm se analizó mediante microscopía Láser Confocal (CLSM) para observar su estructura tridimensional y la viabilidad bacteriana. La comparación de cada bacteria en ambos discos en cada tiempo de estudio se realizó mediante comparación de medias (t de student). Para el estudio de la evolución en el tiempo de cada especie en ambos discos se realizó el análisis de la variancia (ANOVA). Resultados: En este trabajo se encontraron algunas diferencias estadísticamente significativas en los recuentos bacterianos. El numero de unidades formadoras de colonias (UFC)/mL de F. nucleatum en el material A1 en el tiempo de incubación de 24h, y de A. actinomycetemcomitans en el material A1 en el tiempo de incubación de 48h, han sido menores que en HA siendo la diferencia estadísticamente significativa. Mediante Microscopia Láser Confocal (CLSM) se observaron diferencias estructurales en el desarrollo del biofilm en el material A1 en comparación con el control. Conclusiones: Este estudio demuestra que el recubrimiento con Ecovidrio G3, altera el desarrollo del biofilm bacteriano. Los cambios estructurales son visibles por Microscopia Laser Confocal observandose también diferencias significativas en algunos de los recuentos bacterianos. Son resultados preliminares, y se necesita aumentar el numero de experimentos para confirmar estos resultados

The Impact of <i>Candida albicans</i> in the Development, Kinetics, Structure, and Cell Viability of Biofilms on Implant Surfaces—An In Vitro Study with a Validated Multispecies Biofilm Model

This study aimed to evaluate the impact of Candida albicans on subgingival biofilm formation on dental implant surfaces. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to compare biofilm structure and microbial biomass in the presence and absence of the fungus after periods of 24, 48, and 72 h. Quantitative polymerase chain reaction (qPCR) was used to quantify the number of viable and total micro-organisms for each of the biofilm-forming strains. A general linear model was applied to compare CLSM and qPCR results between the control and test conditions. The biofilm developed with C. albicans at 72 h had a higher bacterial biomass and a significantly higher cell viability (p C. albicans, there was a significant increase in counts of Fusobacterium nucleatum and Porphyromonas gingivalis and in the cell viability of Streptococcus oralis, Aggregatibacter actinomycetemcomitans, F. nucleatum, and P. gingivalis. Using a dynamic in vitro multispecies biofilm model, C. albicans exacerbated the development of the biofilm grown on dental implant surfaces, significantly increasing the number and cell viability of periodontal bacteria

The Antimicrobial Activity of Curcumin and Xanthohumol on Bacterial Biofilms Developed over Dental Implant Surfaces

In search for natural products with antimicrobial properties for use in the prevention and treatment of peri-implantitis, the purpose of this investigation was to evaluate the antimicrobial activity of curcumin and xanthohumol, using an in vitro multi-species dynamic biofilm model including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of curcumin (5 mM) and xanthohumol (100 &mu;M) extracts, and the respective controls, were evaluated with 72-h biofilms formed over dental implants by their submersion for 60 seconds. The evaluation was assessed by quantitative polymerase chain reaction (qPCR), confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). For the data analysis, comparisons were tested applying ANOVA tests with post-hoc Bonferroni corrections to evaluate the antimicrobial activity of both extracts. With qPCR, statistically significant reductions in bacterial counts were observed for curcumin and xanthohumol, when compared to the negative control. The results with CLSM and SEM were consistent with those reported with qPCR. It was concluded that both curcumin and xanthohumol have demonstrated antimicrobial activity against the six bacterial species included in the dynamic in vitro biofilm model used