Examinando por Materia "Estudio in vitro"

Mostrando 1 - 3 de 3

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.
Acceso abierto
Whitening effectiveness of three commercial dentifrices for the removal of extrinsic dental stains. in vitro study, Lima-2020
(Universidad Privada Norbert Wiener, 2020-11-30) Julca Huaman, Lisseth; Aguirre Morales, Anita Kori
Objective: This in vitro study determined the effectiveness of three commercial whitening toothpastes in removing extrinsic dental stains. Materials and Methods: Thirty human premolars were sectioned mesio-distally to obtain two segments, resulting in 60 enamel surfaces, which were divided into four groups (G1, G2, G3, G4). G1 served as the negative control group using conventional fluoride toothpaste, while G2 used Colgate® Luminous White, G3 used Oral-B 3D White Perfection, and G4 used Sensodyne Whitening. All samples were immersed in black tea for seven days. Color changes in the samples were measured using a Vita Easyshade® 4.0 digital spectrophotometer after black tea staining and after brushing on the first, seventh, and fourteenth days. Results: The four groups were compared over three time points, with significant differences observed only at T3 (p > 0.05). At this stage, only two toothpastes proved effective: Oral-B 3D White Perfection (6.82 ± 5.61) and Colgate Luminous White (5.53 ± 5.03). Conclusions: It was concluded that only two whitening toothpastes, Oral-B 3D White Perfection and Colgate Luminous White, are effective in removing extrinsic dental stains.