Genotoxicity in oral epithelial cells in children caused by nickel in metal crowns.

The micronucleus (MN) assay evaluates the effects of low doses of genotoxic carcinogens and can detect structural lesions that survive mitotic cycles. The objective of this study was to determine both the genotoxicity of nickel (Ni) in buccal epithelial cells and the urinary excretion of Ni in children with metal crowns. This was a prospective longitudinal study based on 37 patients selected at the Facultad de Odontología de la Universidad Autónoma de Coahuila. MN assays were performed using buccal cells from the 37 patients, and Ni levels were determined from urine samples using inductively coupled plasma mass spectrometry at 1 (basal value), 15, and 45 days following the placement of crowns in each patient. Ni urinary excretion levels increased from 2.12 ± 1.23 to 3.86 ± 2.96 mg Ni/g creatinine (P < 0.05) and the frequency of exposed micronuclei increased from 4.67 ± 0.15 to 6.78 ± 0.167/1000 cells (P < 0.05) between 1 and 45 days post-crown placement. These results suggest that odontological exposure to metal crowns results in genotoxic damage at the cellular level of the oral mucosa and an increase in the urinary excretion of Ni within 45 days of exposure.

Zein as biodegradable material for effective delivery of alkaline phosphatase and substrates in biokits and biosensors.

A biodegradable material, zein, is proposed as a reagent delivery platform for biokits and biosensors based on alkaline phosphatase (ALP) activity/inhibition in the presence of phosphatase substrates. The immobilization and release of both the substrate and/or the active ALP, in a biodegradable and low-cost material such as zein, a prolamin from maize, and in combination with glycerol as plasticizer have been investigated. Three zein-based devices are proposed for several applications: (1) inorganic phosphorus estimation in water of different sources (river, lake, coastal water and tap water) with a detection limit of 0.2mg/L - compared to at least 1mg/L required by legislation, (2) estimation of ALP in saliva and (3) chlorpyrifos control in commercial preparations. The single-use kits developed are low cost, easy and fast to manufacture and are stable for at least 20 days at -20°C, so the zein film can preserve and deliver both the enzyme and substrates.

Antibacterial Activity Analysis of Hydroxyapatite Based Materials with Fluorine and Silver / Análisis de la Actividad Antibacteriana de Materiales a Base de Hidroxiapatita con Flúor y Plata

ABSTRACT This investigation aims to evaluate the antibacterial activity of nanostructured hydroxyapatite based materials doped with silver and fluorine, to be used as a biomaterial with antibacterial activity. Four different formulations were prepared by combustion method: hydroxyapatite, hydroxyapatite-fluorine, hydroxyapatite-silver-fluorine and hydroxyapatite-silver, with 2% of the doping agents. X-ray diffraction technique was used to determine the mineralogy, identifying the presence of Ca5(PO4)3OH, Ca2P2O7, Ag3PO4, AgCa10(PO4)7 Ca5(PO4)3F and CaF2 phases for the studied samples. Scanning electron microscopy was used to study the morphological structure and it showed homogeneous crystallization of the hydroxyapatite and the inclusion of dopant agents. The antibacterial activity was determined using a modified inhibition test zone to observe if the bacteria (E. faecalis) was susceptible to the antimicrobial agent by the appearance of the zone of inhibition on the agar plate. Both the hydroxyapatite-silver and the hydroxyapatite-silver-fluorine materials generated an inhibition zone. It was possible to determine the minimum inhibitory concentration needed to kill most viable organisms after 48 hours of incubation using the broth microdilution method, resulting in 75 µg/ml and 200 µg/ml for the hydroxyapatite-silver and the hydroxyapatite-silver-fluorine formulation, respectively. These materials could be used for the development of new biomaterials that can be used in dental applications.

RESUMEN El objetivo de esta investigación es analizar la actividad antibacteriana de materiales nanoestructurados a base de hidroxiapatita con iones de flúor y plata que le confieran características particulares para que pueda ser utilizado como un biomaterial con actividad antimicrobiana. Se realizaron cuatro formulaciones distintas: hidroxiapatita, hidroxiapatita-flúor, hidroxiapatita-plata-flúor e hidroxiapatita-plata con un 2% de los agentes dopantes. La síntesis del material se realizó a través del método de combustión. La caracterización mineral se realizó a través de difracción de rayos X identificando las siguientes fases en las diversas formulaciones: Ca5(PO4)3OH, Ca2P2O7, Ag3PO4, AgCa10(PO4)7 Ca5(PO4)3F and CaF2. La estructura morfológica se analizó a través de microscopía electrónica de barrido que muestra la formación de estructuras compactas, presencia de cristales y la incrustación de flúor y plata. Se analizó la actividad antimicrobiana utilizando una prueba modificada para la observación del halo de inhibición, encontrándose solamente que los materiales que contenían plata-flúor y plata generaron dicho halo de inhibición. Por otra parte, usando la prueba de microdilución en pozo se encontró que la concentración mínima inhibitoria para el material de HA-Ag fue de 75 μg/ml y para el material de HA-Ag-F fue de 200 μg/ml, después de 48 horas de incubación utilizando E. faecalis.

Development of a polydimethylsiloxane-thymol/nitroprusside composite based sensor involving thymol derivatization for ammonium monitoring in water samples.

This report describes a polydimethylsiloxane (PDMS)-thymol/nitroprusside delivery composite sensor for direct monitoring of ammonium in environmental water samples. The sensor is based on a PDMS support that contains the Berthelot's reaction reagents. To prepare the PDMS-thymol/nitroprusside composite discs, thymol and nitroprusside have been encapsulated in the PDMS matrix, forming a reagent release support which significantly simplifies the analytical measurements, since it avoids the need to prepare derivatizing reagents and sample handling is reduced to the sampling step. When, the PDMS-thymol/nitroprusside composite was introduced in water samples spontaneous release of the chromophore and catalyst was produced, and the derivatization reaction took place to form the indothymol blue. Thus, qualitative analysis of NH4(+) could be carried out by visual inspection, but also, it can be quantified by measuring the absorbance at 690 nm. These portable devices provided good sensitivity (LOD<0.4 mg L(-1)) and reproducibility (RSD <10%) for the rapid detection of ammonium. The PDMS-NH4(+) sensor has been successfully applied to determine ammonium in water samples and in the aqueous extracts of particulate matter PM10 samples. Moreover, the reliability of the method for qualitative analysis has been demonstrated. Finally, the advantages of the PDMS-NH4(+) sensor have been examined by comparing some analytical and complementary characteristics with the properties of well-established ammonium determination methods.

Pyodermatitis-pyostomatitis vegetans: report of a case and review of the literature.

Pyodermatitis-pyostomatitis vegetans is a benign, rare disorder characterized by a pustular eruption in the oral mucosa and vegetating plaques involving the groin and axillary folds. Its association with inflammatory bowel disease is well established. We report the case of a 49-year-old-white man with ulcerative colitis who manifested a vegetating, annular plaque in the left inguinal region of 2 months' duration. Oral examination disclosed an erythematous mucosa with multiple painful pustules involving the labial and gingival mucosa. Histopathologic study demonstrated epidermal hyperplasia and an inflammatory infiltrate composed mostly of neutrophils and eosinophils, grouped into microabscesses within the epidermis and with a bandlike configuration in the upper dermis. Results of direct and indirect immunofluorescence studies were negative. We discuss the differential diagnosis between pyodermatitis-pyostomatitis vegetans and pemphigus vegetans.

Adherence inhibition of Streptococcus mutans on dental enamel surface using silver nanoparticles.

The aim of this ex vivo study was to evaluate the adherence capacity of Streptococcus mutans after being exposed to three different sizes of silver nanoparticles on healthy human dental enamel. Three different sizes of silver nanoparticles (9.3, 21.3 and 98 nm) were prepared, characterized and an adherence testing was performed to evaluate their anti-adherence activity on a reference strain of S. mutans on healthy dental enamel surfaces. Colony-Forming Unit count was made for adherence test and light microscopy, atomic force microscopy and scanning electron microscopy were used to compare qualitative characteristics of S. mutans. 9.3 nm and 21.3 nm groups did not show differences between them but statistical differences were found when 9.3 nm and 21.3 nm groups were compared with 98 nm and negative control groups (p<0.05). Microscopy analysis shows a better inhibition of S. mutans adherence in 9.3 nm and 21.3 nm groups than the 98 nm group when compared with control group. Silver nanoparticles showed an adherence inhibition on S. mutans and the anti-adherence capacity was better when silver nanoparticles were smaller.

Functional maintenance of arch-length.

This article discussed on overall concept of the etiology of arch-length loss, general indications and contraindications for Functional Space Maintenance and described in detail the methods for constructing a Fixed Functional Space Maintainer utilizing stainless steel crowns for abutments and pontics.

Mechanical assessment of interocclusal clearance.

Appropriate design considerations for pediatric or adult appliances are a part of diagnosis as well as therapy. These include occlusal factors. The occlusal considerations warrant accurately accommodating the cast metal framework or wire elements of a removable appliance. A gauge measurement can be accomplished utilizing the device we describe.

Cinta vaginal libre de tensión modificado, asociado a cirugía vaginal en el tratamiento de la incontinencia de orina de esfuerzo / Modified tension free vaginal tape, associated to vaginal surgery in the treatment of the stress urinary incontinence

El objetivo principal de este trabajo es introducir una nueva técnica quirúrgica para la corrección de la incontinencia urinaria de la pacientes ginecológica. Se describe la técnica del TVT (tensión-free vaginal tape) y sus modificaciones. El estudio, incluyó 23 pacientes portadoras de Incontinencia de Orina de Esfuerzo (IOE), la mayoría de ellas asociadas a prolapso genital, que fueron operadas en Clínica Dávila entre Septiembre de 1999 y Julio de 2001. En todas las pacientes se realizó sling suburetral con malla de polypropyleno (TVT modificado), asociado a plastia vaginal anterior y posterior en 16 y a histerectomía vaginal en 9. La anestesia empleada fue espinal o epidural. El porcentaje de curación es de 95,7 por ciento, con un período de seguimiento promedio de 10 meses con un rango de 1 a 22 meses. La sonda Foley se usó por 12 horas en 19 pacientes (95 por ciento), fue necesaria por 72 horas en un caso (5 por ciento) y en 3 no se usó (13 por ciento). Una paciente necesitó cateterización vesical en la segunda semana. Una paciente presentó hematoma en el espacio de Retzius, no hubo perforaciones vesicales. Basados en estos resultados, concluimos que el TVT simultáneo a otras cirugías vaginales, es una alternativa eficaz y segura en el tratamiento de la IOE, asociado a la relajación del piso pélvico