Alma Blásida Concepción Elizaur Benitez Catirse

The influence of mouthrinses and simulated toothbrushing on the surface roughness of a nanofilled composite resin

The aim of this study was to determine the influence of mouthrinses on the surface roughness of a nanofilled composite resin after toothbrushing. One hundred nanofilled composite resin specimens were prepared and randomly distributed into two groups-brushed and non-brushed-and then assigned to five subgroups, according to the mouthrinse solutions (n = 10): Colgate Plax Fresh Mint, Oral B, Cepacol, Colgate Plax, and artificial saliva. Each sample was immersed in 20 mL of the mouthrinses for 1 minute, 5 days per week, twice a day, for a 3-week period. The control group used in the study was one in which the specimens were not subjected to brushing and remained only in artificial saliva. Toothbrushing was performed once a week for 1 minute, for 3 weeks. Surface roughness measurements (Ra) were performed after the immersion period and toothbrushing, by means of a profilometer. Data were analyzed by two-way ANOVA and Tukeys test. Analysis revealed that the association between toothbrushing and Colgate Plax Fresh Mint produced the lowest surface roughness (p < 0.05). All other groups tested (Oral B, Cepacol, Colgate Plax, artificial saliva) exhibited no statistically significant differences between surfaces, whether subjected to toothbrushing or not (p < 0.05). It was concluded that the surface roughness of the nanofilled composite resin tested can be influenced by the mouthrinse associated with toothbrushing.

A Singular Method to Compare Dental Radiographic Films Used to Study Maxillofacial Structures

El objetivo de este articulo es presentar un metodo singular y practico para comparar roentgenogramas, referentes a la densidad optica y al contraste. Este metodo se indica especificamente para la investigacion con el penetrometro stepwedge y el fotodensitometro

Influence of fluoride-containing solutions on the translucency of flowable composite resins

The aim of this study was to evaluate the influence of fluoride-containing solutions on the translucency of flowable composite resins, with respect the immersion time. Flow-It! (FI) and Natural Flow (NF) composite resins and three commercial brands of fluoride-containing solutions (Fluordent, Fluorgard and Oral B) were used. Specimens were prepared and stored in the solutions at 37°C, until the measurements were made after the following treatments: T1 - after 1 hour in relative humidity; T2 - after 1 h in solution; T3 - 24 h; T4 - 48 h; T5 - after a week; from T9, the measurements were accomplished weekly, up to 30-day immersion. To obtain translucency values an electrophoresis equipment was employed. Data were submitted to ANOVA and Tukey tests. The results disclosed that NF showed highest values of translucency and was statistically different from FI (p< 0.001). As regards the solutions, Fluordent and Oral B presented similar values and were statistically superior to Fluorgard (p< 0.05). Concerning the immersion time, similar results were observed for the different evaluation periods. It may be concluded that the fluoride-containing solutions affected the translucency of the composite resins, independently of the materials used. Among the tested resins, NF presented the best performance.

Surface roughness of composite resins subjected to hydrochloric acid.

The purpose of this study was to determine the influence of hydrochloric acid on surface roughness of composite resins subjected to brushing. Sixty samples measuring 2 mm thick x 6 mm diameter were prepared and used as experimental units. The study presented a 3x2 factorial design, in which the factors were composite resin (n=20), at 3 levels: microhybrid composite (Z100), nanofilled composite (FiltekTM Supreme), nanohybrid composite (Ice), and acid challenge (n=10) at 2 levels: absence and presence. Acid challenge was performed by immersion of specimens in hydrochloric acid (pH 1.2) for 1 min, 4 times per day for 7 days. The specimens not subjected to acid challenge were stored in 15 mL of artificial saliva at 37 oC. Afterwards, all specimens were submitted to abrasive challenge by a brushing cycle performed with a 200 g weight at a speed of 356 rpm, totaling 17.8 cycles. Surface roughness measurements (Ra) were performed and analyzed by ANOVA and Tukey test (p≤0.05). Surface roughness values were higher in the presence (1.07±0.24) as compared with the absence of hydrochloric acid (0.72±0.04). Surface roughness values were higher for microhybrid (1.01±0.27) compared with nanofilled (0.68 ±0.09) and nanohybrid (0.48±0.15) composites when the specimens were not subjects to acid challenge. In the presence of hydrochloric acid, microhybrid (1.26±0.28) and nanofilled (1.18±0,30) composites presents higher surface roughness values compared with nanohybrid (0.77±0.15). The hydrochloric acid affected the surface roughness of composite resin subjected to brushing.

EFECTO TÓXICO DEL IÓN CADMIO SOBRE LA GLÁNDULA SUBMANDIBULAR DE RATA ADULTA

El estudio tuvo por objetivo investigar histometricamente los efectos toxicos de la exposicion al ion cadmio sobre la glandula submandibular en rata adulta. Ratas machos, de peso aproximado a 170 g, recibieron, en el bebedero, una solucion de 300 mg de cloruro de Cd/l de agua, durante 6 meses. Otro grupo de animales, despues del tratamiento, permanecio en recuperacion durante un periodo adicional de 6 meses. El parenquima de las glandulas submandibulares mostro marcada diferencia entre los animales tratados y controles. Los acinos de las glandulas de las ratas intoxicadas con Cd, eran menores, de forma irregular y con celulas degeneradas. Los nucleos variaron de tamano pero no de forma. Los ductos estriados, granulosos y excretores estaban desorganizados, mostrando nucleos menores. El cuadro histologico de la glandula submandibular de las ratas sometidas, a recuperacion de la intoxicacion, durante 6 meses fue semejante al de los controles. Este resultado fue confirmado mediante el estudio histometrico. Basados en la literatura, los autores afirman que la metalotioneina actua como agente desintoxicante uniendose al Cd y que la disminucion de su sintesis aumenta la concentracion de Cd libre, provocando danos al ADN e inhibiendo la sintesis proteica, como fue observado en el presente trabajo

Densidad ósea bilateral comparativa del ángulo de la mandíbula

El objetivo de este estudio fue realizar una comparacion bilateral de la densidad de mandibula en pacientes jovenes de ambos sexos con computadora densitometrica osea. Fueron obtenidas 50 radiografias panoramicas de pacientes jovenes entre 18 y 23 anos de edad (Grupo A = 25 femenino y el grupo B = 25 masculino), utilizando el mismo equipo de radiografia (Siemens, 1 OKvp, 7mA). Se escaneo con una resolucion de 282,110 pixels, transfiriendose luego a un computador para el estudio por medio del programa SIDEXIS (Sirona, USA) para analizar el desempeno densitometrico de hueso. Los sitios bilaterales fueron estandarizados con el objetivo de medir la densidad de hueso. Los datos obtenidos fueron registrados y sometidos a analisis estadistico. Las medias y los desvios padron fueron obtenidos en pixels, para el lado derecho y el lado izquierdo, respectivamente: Grupo A = 154,36±36,90 y 186,12±31,41, grupo B = 162,07±34,94 y 180,15±30,96. Estos valores muestran la diferencia estadistica entre lados y grupos diferentes (p<0,05), con una densidad mas alta de hueso en el lado izquierdo en ambos grupos, especialmente en grupo A

Evaluación de la dureza superficial en amalgamas en función de tipos de aleaciones, momentos y tipos de pulimentos

The aim of this study was to analyze in vitro surface hardness (micro-indentation tester Wolpert) of different types of amalgam alloys varying the technique and polishing time. Tested were the amalgam: Velvalloy, Permite e Dispersalloy. For each material, 2 polishing techniques were accomplished: T1 (bladed finishing burs + abrasive rubber points + pumice-water slurry in Robinson polishing brush) and; T2 (abrasive rubber points + pumice-water slurry in Robinson polishing brush), at 2 periods of time: P1 (immediately - 15 min after condensation) and P2 (after 24 h). For each experimental condition, 5 samples were prepared. For each sample, 2 indentations were taken and the average was determined. Were made analysis using ANOVA and Tukey test. Were concluded that: a) using the Permite alloy with polishing after 24 h the surface hardness of restoration will be higher; b) the technique T2 enhances the hardness of dental amalgams and c) alloy Permite with polished immediately were statisticaly equal than Velvalloy polished after 24 h.