Examinando por Materia "In vitro study"

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Acceso abierto
Comparative in vitro study of the resistance to fracture in two types of bis-acrylic resin, Lima – Peru 2021
(Universidad Privada Norbert Wiener, 2021-10-21) Perez Acosta, Josefina; Rojas Ortega, Raúl Antonio
The present study, titled "In vitro comparative study of fracture resistance in two types of bis-acrylic resins, Lima – Peru 2021," aimed to compare the fracture resistance of two types of bis-acrylic resins, Acrytemp® and Protemp 4™. A hypothetical-deductive method was used, with a quantitative, applied, cross-sectional, prospective, experimental approach, and a post-test experimental design. A sample of 36 bis-acrylic resin cylinders (Acrytemp® and Protemp 4™) was studied, divided into two groups of 18. These analysis units had dimensions of 4 mm in diameter by 8 mm in height and were subjected to compression using the CMT-5L LG universal testing machine. Results: The fracture resistance of Acrytemp® resin showed a mean of 150.9544 MPa, while Protemp 4™ resin showed a mean of 272.5817 MPa. Hypothesis testing using the Student's t-test yielded a p-value of 0.000, which is less than the significance level of p≤0.05, thus accepting the alternate hypothesis. Conclusion: There is a statistically significant difference in fracture resistance between the two types of bis-acrylic resins.
Acceso abierto
Volumetric variation of two silicones by condensation SPEEDEX and ZETAPLUS when polymerizing over time
(Universidad Privada Norbert Wiener, 2021-10-21) Dominguez Ruiz, Yamyr; Llerena Meza De Pastor, Verónica
Objective: To compare in vitro the volumetric differences of two condensation silicones (Speedex and Zetaplus) at 5 and 30 minutes, 1, 24, and 48 hours. Materials and Methods: A total of 24 samples were obtained from two brands of heavy condensation silicones (Speedex and Zetaplus) in a 5cc³ matrix. The materials were activated and subsequently weighed on a sensitive digital scale at different times following activation. The volumes of the samples were calculated from the weights obtained and then compared. Results: Non-parametric Friedman's test and Student's t-test for independent groups were performed. The mean volumetric variation in the Zetaplus group was -0.00012 with a standard deviation of 0.00001, while the Speedex group showed a mean of -0.00009 with a standard deviation of 0.00002. Statistically significant differences were found between the two groups (p<0.05). At 30 minutes, volumetric variations were smaller but still significantly different between the silicones. Conclusions: Speedex heavy silicone exhibited significantly lower volumetric variation than Zetaplus silicone at 5 and 30 minutes, but not at later times. Both condensation silicones, Speedex and Zetaplus, showed significant volumetric variations at 5 and 30 minutes, 1 hour, 24 hours, and 48 hours.