• Comparación in vitro de la alteración dimensional del modelo definitivo según el tiempo de vaciado de la silicona por condensación

      Pagán Yábar, Luis Antonio; Ramírez Necochea, Dreyci Mildred (Universidad Peruana de Ciencias Aplicadas (UPC)PE, 01/12/2014)
      Materials and methods: 36 impressions were taken to a stainless steel model with condensation silicone Oranwash Zetaplus and divided into 3 groups according to the emptying time (0, 0.5 and 72 hours). To determine the dimensional alteration of the final models compared to the master model, 8 specific locations were measured with a specialized coordinate machine, model Contura G2 with ZEISS Scanning contact technology. Results: The non-parametric test of Wilcoxon was used for this study. It was found that only 6 of 8 locations had statistically significant differences: A, C, D, E, F y G. We found there´s more dimensional changes in models poured at 0 and 72 hours. However, it´s important to say that each location is independent from the other, each one with different values as shown in the master model, so that could be related to the fact that 2 of these 8 locations don’t have statistically significant results because in prosthetic works cause each of these locations is a critical point in the adaptation and cannot be taken as one. Conclusions: Despite of being a material with excellent reproduction properties, silicones condensation present bigger dimensional alteration when models are emptied long after taking the impression, which means the more time you wait to pour the models, the more dimensional alteration you will have. So, we can conclude that it´s recommended to make the casting with plaster 0.5 h after we´ve taken the impression because if we wait more time, we´ll find more distortion in the final design of the model, the same as if we pour them immediately, cause the impression material also needs time to recover elastically and be more stable.
      Acceso abierto
    • Comparación in vitro del desgaste compensatorio de tres instrumentos de acceso (Gates Glidden, IntroFile FlexMaster® y SX ProTaper®) utilizados en endodoncia

      Vertiz Falla, Augusto Rensso; Vargas Mateos, Shiovan Yamileth (Universidad Peruana de Ciencias Aplicadas (UPC)PE, 01/12/2014)
      Objective: This in vitro study aimed to compare preflaring of three instruments of access with Gates Glidden, IntroFile FlexMaster® and SX ProTaper® used in endodontic treatment. Materials and methods: The preflaring was performed over 30 plastic upper molars (VDW, Germany) standardized which were divided into three groups of ten. Teeth were divided and implemented with Gates Glidden, IntroFile FlexMaster® and SX ProTaper® . This procedure was done by a single trained operator. For measuring the root canals, crowns of teeth were cut transversely to UCA level with a fine diamond disc. Measures corresponding to 5 anatomical references were evaluated: remaining mesial of mesiobuccal canal, vestibular of mesiobuccal canal, mesial of distobuccal canal, vestibular of distal canal and distance between wall of distal of mesiobuccal canal with wall of mesial of distalbuccal canal. The results were analyzed in microns (µm) through a stereomicroscope with a Leica Microsystems 56D software. Results: Statistically significant differences between experimental groups were found. Introfile limes produce minor discrepancy of compensatory attrition. The main discrepancy was found in group 1 (Gates Glidden) unlike the other instruments. Conclusions: The IntroFile FlexMaster® limes present lower cutting angle which produce a conservative preflaring in comparison to Gates Glidden strawberries which produce a more aggressive preflaring.
      Acceso abierto
    • Evaluación in vitro del efecto antibacteriano de cinco propóleos peruanos sobre cepas de Streptococcus mutans (ATCC 25175) y Streptococcus sanguinis (ATCC 10556)

      Mayta Tovalino, Frank Roger; Del Valle Mendoza, Juana Mercedes; Jara Muñoz, Rocío del Pilar (Universidad Peruana de Ciencias Aplicadas (UPC)PE, 01/12/2014)
      El objetivo fue evaluar in vitro el efecto antibacteriano de cinco propóleos peruanos sobre cepas de Streptococcus mutans (ATCC 25175) y Streptococcus sanguinis (ATCC 10556) teniendo un diseño de estudio experimental in vitro, realizado en el laboratorio de Microbiología de la Universidad Peruana de Ciencias Aplicadas. Materiales y métodos: se comparó el efecto antibacteriano de cuatro marcas comerciales de propóleo Tintura de propóleo Farmagel, Tintura de propóleo Max, Madre Natura, Kaita® y un extracto metanólico de propóleo de Oxapampa, el cual se elaboró en el laboratorio de Bioquímica de la UPC, como control (+) la clorhexidina al 0.12%. Para este estudio se utilizó 10 pocillos por cada extracto de propóleo, para el Streptococcus mutans y para el Streptococcus sanguinis individualmente. Se desarrolló con la técnica “Agar overlay interference test”, para lo cual se utilizó 200ml de Agar BHI homogenizado con las bacterias de manera independiente (un frasco por bacteria). Se distribuyó este agar en las placas, una vez solidificado se realizaron los pocillos con 150μL de los distintos tipos de propóleo y para el grupo control, se utilizó clorhexidina al 0.12%. Terminado este proceso se colocó en la cámara de anaerobiosis a 37°C, durante 72 horas. Por último, se realizó la medición del halo inhibitorio con una regla Vernier. Resultados: El extracto metanólico de propóleo de Oxapampa presentó halos de inhibición de mayor tamaño con una media de 33.15 + 3.26 mm frente a las cepas de Streptococcus mutans (ATCC 25175), para el Streptococcus sanguinis (ATCC 10556) su media fue de 23.23 + 0.82 mm. En el caso de los 4 extractos de propóleo comerciales, sólo 3 de ellos (Tintura de propóleo Farmagel, Madre Natura y Kaita®), tuvieron actividad antibacteriana frente a las cepas estudiadas, en todos los casos la actividad antibacteriana es menor que el control (+). Conclusiones: El extracto metanólico de propóleo de Oxapampa elaborado en el laboratorio tiene mayor actividad antibacteriana que los extractos comerciales frente a las cepas Streptococcus mutans (ATCC 25175) y Streptococcus sanguinis (ATCC 10556). De los 4 propóleos comerciales evaluados en el estudio, Tintura de propóleo Farmagel, Kaita®, Madre Natura y Tintura de propóleo Max, sólo tres de ellos tiene actividad antibacteriana frente a las cepas de Streptococcus mutans (ATCC 25175) y Streptococcus sanguinis (ATCC 10556).
      Acceso abierto