Alejandro Donohue-Cornejo

Antimicrobial Properties of Biofunctionalized Silver Nanoparticles on Clinical Isolates of Streptococcus mutans and Its Serotypes

(1) Background: Streptococcus mutans (S. mutans) is the principal pathogen involved in the formation of dental caries. Other systemic diseases have also been associated with specific S. mutans serotypes (c, e, f, and k). Silver nanoparticles (SNP) have been demonstrated to have good antibacterial effects against S. mutans; therefore, limited studies have evaluated the antimicrobial activity of biofunctionalized SNP on S. mutans serotypes. The purpose of this work was to prepare and characterize coated SNP using two different organic components and to evaluate the antimicrobial activity of SNP in clinical isolates of S. mutans strains and serotypes; (2) Methods: SNP with bovine serum albumin (BSA) or chitosan (CS) coatings were prepared and the physical, chemical and microbiological properties of SNP were evaluated; (3) Results: Both types of coated SNP showed antimicrobial activity against S. mutans bacteria and serotypes. Better inhibition was associated with smaller particles and BSA coatings; however, no significant differences were found between the different serotypes, indicating a similar sensitivity to the coated SNP; (4) Conclusion: This study concludes that BSA and CS coated SNP had good antimicrobial activity against S. mutans strains and the four serotypes, and this study suggest the widespread use of SNP as an antimicrobial agent for the inhibition of S. mutans bacteria.

Dose-Dependent Antimicrobial Activity of Silver Nanoparticles on Polycaprolactone Fibers against Gram-Positive and Gram-Negative Bacteria

The adhesion ability and adaptability of bacteria, coupled with constant use of the same bactericides, have made the increase in the diversity of treatments against infections necessary. Nanotechnology has played an important role in the search for new ways to prevent and treat infections, including the use of metallic nanoparticles with antibacterial properties. In this study, we worked on the design of a composite of silver nanoparticles (AgNPS) embedded in poly-epsilon-caprolactone nanofibers and evaluated its antimicrobial properties against various Gram-positive and Gram-negative microorganisms associated with drug-resistant infections. Polycaprolactone-silver composites (PCL-AgNPs) were prepared in two steps. The first step consisted in the reduction in situ of Ag+ ions using N,N-dimethylformamide (DMF) in tetrahydrofuran (THF) solution, and the second step involved the simple addition of polycaprolactone before electrospinning process. Antibacterial activity of PCL-AgNPs nanofibers against E. coli, S. mutans, K. pneumoniae, S. aureus, P. aeruginosa, and B. subtilis was evaluated. Results showed sensibility of E. coli, K. pneumoniae, S. aureus, and P. aeruginosa, but not for B. subtilis and S. mutans. This antimicrobial activity of PCL-AgNPs showed significant positive correlations associated with the dose-dependent effect. The antibacterial property of the PCL/Ag nanofibers might have high potential medical applications in drug-resistant infections.

Periimplantitis: Revisión de la Literatura

El uso de implantes ha tomado un gran auge en los ultimos anos, sin embargo asi como se ha visto un aumento en la demanda tambien se ha visto un incremento en el fracaso de los mismos, existen multiples razones que intervienen para esto como son; deficiencias en la cantidad y calidad de hueso, patologias oseas preexistentes, mala tecnica quirurgica, implante inadecuado, habito tabaquico, entre otras. La mucositis periimplantaria y la periimplantitis son las primeras causas de complicaciones en los implantes, los pacientes con enfermedades cronico degenerativas, fumadores y con mala higiene son considerados pacientes de riesgo para presentar periimplantitis. La literatura ofrece tratamientos quirurgicos y no quirurgicos los cuales van enfocados a la eliminacion de microorganismos y a la desinfeccion de la superficie del implante, el tratamiento quirurgico como la debridacion y curetaje tienen la finalidad de eliminar la placa bacteriana, desinfectar la superficie del implante asi como retirar el tejido danado por el proceso inflamatorio, el realizar una adecuada historia clinica y valoracion previa, permitira identificar a los pacientes con mayor o menor riesgo de desarrollar periimplantitis, las citas de mantenimiento ayudan a detectar oportunamente posibles complicaciones.

Attention to Rhotacism Language Problem by Oral Surgery and Vibrostimulatory Therapy: A Case Report

La anquiloglosia puede evitar que la lengua entre en contacto con la region anterior del paladar, lo que promueve una deglucion infantil y dificultan la adecuada deglusion en el adulto. Esto tambien puede dar lugar a una mordida abierta y en algunos casos, estar asociada con prognatismo mandibular y problemas de lenguaje como el rotacismo, que se describen como la incapacidad o dificultad para pronunciar el sonido / r /. La exsicion quirurgica del tejido que conecta frenillo de la lengua a la mandibula (frenectomia) y el tratamiento rehabilitador del lenguaje con dispositivos orales funcionales, representan una alternativa de tratamiento para este problema. Un nino de 11 anos de edad, con problemas de lenguaje, malposicion dental y diagnostico de anquiloglosia, fue sometido a frenectomia y tratamiento de rehabilitacion dellenguaje mediante dispositivos orales funcionales durante seis meses. El diagnostico del lenguaje se llevo a cabo en tres periodos de tiempo: antes de la cirugia, cuatro semanas despues de la cirugia y seis meses mas tarde. La combinacion de tratamiento quirurgico y funcionales demostraron ser una alternativa mejor que la terapia quirurgica por si sola. Las terapias combinadas aumentaron la capacidad del habla, asi como funciones de deglucion, por lo tanto, la autoestima del paciente.

Antiadherence and Antimicrobial Properties of Silver Nanoparticles against Streptococcus mutans on Brackets and Wires Used for Orthodontic Treatments

White spot lesions (WSLs) are very frequent alterations during orthodontic treatments causing demineralization of the dental enamel. Various dental treatments have been developed to prevent WSLs; the prevalence and incidence of these lesions remain significantly high. Although silver nanoparticles (AgNPs) have demonstrated good inhibitory effects against several microorganisms, more studies about antiadherence activity on different orthodontic appliance surfaces are necessary. To determine the inhibitory effect and antiadherence activity of AgNPs on the adhesion of S. mutans on surfaces of brackets and wires for orthodontic therapies, two sizes of AgNPs were prepared and characterized. The evaluation of S. mutans adhesion was performed with microbiological assays on surfaces of brackets and orthodontic modules in triplicate. Topographic characteristics of orthodontic brackets and wires were made by scanning electron and atomic force microscopies. All AgNP samples inhibited S. mutans adhesion; however, the smaller AgNPs had better inhibition than the larger ones. The presence of the module influenced the adhesion of S. mutans but not in the activity of AgNPs. The AgNPs used in this study showed to have good antimicrobial and antiadherence properties against S. mutans bacteria determining its high potential use for the control of WSLs in orthodontic treatments.