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Objetivo: El conocimiento sobre las propiedades mecánicas de los materiales dentales es fundamental para una correcta indicación y funcionamiento en la cavidad oral, permitiéndole al profesional optar por el que presente mejor comportamiento durante la masticación. El objetivo de este estudio fue evaluar la resistencia a la compresión de Ionofil Molar® y Vitremer®, según tiempo de exposición en saliva artificial. Materiales y Métodos: Se prepararon 5 muestras para cada material evaluadas a los tiempos 0, 168 y 504 horas en saliva artificial a 37° C, según las especificaciones propuestas por la norma ANSI/ADA n°66. La resistencia a la compresión se determinó sometiendo las muestras a cargas en un equipo de ensayo de fuerzas Instron® a una velocidad de carga de 1 mm/min. Se realizó una prueba de homogeneidad de varianzas, la normalidad se determinó mediante Kolmogorov-Smirnov, y posteriormente un ANOVA. Se realizó el test de Tukey para determinar si existió diferencia significativa entre variables. Resultados: La resistencia compresiva de Vitremer no presentó diferencias estadísticamente significativas en el tiempo (p=0.282), a diferencia de Ionofil Molar, que sí presentó diferencias entre los distintos tiempos (p=0.011). Además en las muestras sin sumergir, no hubo diferencia estadísticamente significativa entre materiales (p=0.091), en cambio sí existió diferencia al cabo de una y tres semanas de exposición (p=0). Conclusión: El vidrio ionómero Vitremer presenta mayor resistencia compresiva a lo largo del tiempo, sin presentar alteraciones significativas en el tiempo al ser inmerso en saliva, a diferencia del Ionofil Molar que disminuyó significativamente su resistencia en las mismas condiciones.

Objective: Understanding the mechanical properties of dental materials is essential for proper indication and a correct functioning in the oral cavity, as it allows the dentist to choose the material that presents better performance during mastication. The aim of this study was to evaluate the compressive strength of Ionofil Molar and Vitremer, according to the exposure time in artificial saliva. Materials: 5 samples were prepared for each material evaluated at 0, 168 and 504 hours in artificial saliva at 37º Celsius, according to the specifications suggested by ANSI/ADA specification No 66. The compressive strength was determined by subjecting the samples to an Instron strength-testing machine at a load speed of 1 mm/min. A test of homogeneity of variance was conducted; normality was determined by Kolmogorov-Smirnov, and ANOVA. Tukey’s test was performed to determine if significant differences existed between variables. Results: Vitremer compressive strength did not show statistically significant differences over time (p=0.282), unlike Ionofil Molar, which did present differences between times (p=0.011). Besides, there were no statistically significant differences in the samples without submerging (p=0.091), unlike after one to three weeks of exposure, were a difference did exist (p=0). Conclusion: Vitremer has greater compressive strength over time, without showing significant changes in time after being immersed in saliva, unlike Ionofil Molar, whose resistance decreased significantly under the same conditions.

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Piglets appear to be neurologically sensitive to intrapartum asphyxia. Our aim was to investigate the short-term neurophysiologic consequences of intrapartum asphyxia in piglets. We studied 10 piglets suffering intrapartum asphyxia and 10 control piglets. Glucose and blood gas levels, tympanic membrane temperature, and body weight were measured within the first 2 min after birth. Animals were followed up for a 5-day period. As surrogated markers of piglets' neurological function, a viability score and the time elapsed from birth to the first contact with the maternal udder were recorded. In the control group, temperature and blood pH levels at birth were significantly higher (p < or = .001), whereas calcium, lactate and PCO2 levels were statistically lower (p < or = .05) than in the piglets experiencing intrapartum asphyxia. Lower temperature and blood pH levels as well as higher blood PCO2 and lactate levels were observed in piglets with lower viability scores and in piglets with prolonged times until first udder contact. At the end of the study, asphyxiated piglets weighed on average 200 g less (p = .023) than control piglets. In conclusion, intrapartum asphyxia in spontaneously born piglets was associated with signs of acute neurological dysfunction and lower weight gain, supporting the hypothesis that they may be used as a naturalistic model for the study of asphyxia in newborns.

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A DNA vaccine, using a pCl-neo plasmid encoding the glycoprotein gene of a Mexican isolate of rabies virus, was developed to induce long-lasting protective immunity against rabies virus in dogs. The aim of this work was to evaluate the intranasal (IN) vaccination route in mice and dogs. Mice and dogs were immunized via the intramuscular (IM) and IN routes. Mice received 50 microg of DNA vaccine, a booster on day 30, using the same doses and routes, and on day 90 they were challenged. Dogs received 100 microg of DNA vaccine, with a booster on day 180, and immune responses were studied on day 210. Virus-neutralizing antibodies were detected in blood sera (up to 0.5 IU) in animals immunized via the IN route and when the animals were submitted to a booster, the levels of neutralizing antibodies increased. Animals vaccinated via the IM route presented higher neutralizing antibody titres than those vaccinated IN. Control groups lacked anti-rabies antibodies. On day 90, mice were challenged. From these, a 100 % of the IM vaccinated mice, and an 80 % of the IN vaccinated mice survived the challenge. No animals from the control group survived. Dogs revealed significant virus-neutralizing antibody titres (up to 0.5 IU) on day 30 and, after booster, on day 210 neutralizing antibody titre was higher than 1.8 IU. The main advantage of using DNA vaccines over traditional live ones is that there is no contamination with viruses that could be disseminated in the environment and reproduced in susceptible animals. This study demonstrated that pGQH was succesful when administrated via the IN route. IN vaccination seems attractive due to its easy application and mucosal protection. This form of vaccination could also be advantageous in domestic animal vaccination campaigns, for it is less stressful than the parenteral route (no painful shots).

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A new biliary-enteric derivation was used in one group of mongrel puppies to avoid reflux and its complications. A Y-en-Roux derivation in one pared group of puppies was used also. There was a substantial complications decrease in the first puppies, but do not stop at all contamination in the bile duct tree and liver.

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In order to investigate the possible unwanted late effects of vessel cicatrization during growth, especially after the section and terminal-terminal arterial anastomosis, a study was carried out in 28 piglets using three different surgical anastomosis techniques as well as three different types of sutures. Results show that the smaller the diameter of the vessel and when for its surgical correction suture techniques using separate and combined stitches are used, in addition to non absorbent material, a greater amount of suppression is seen at the site of anastomosis during arterial growth. Less suture material is recommended (of lesser thickness) as well as continuous suture techniques as the diameter of the vessels to be sutured decrease.

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