Examinando por Materia "Resistencia a la flexión"

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Acceso abierto
Comparison of the flexural resistance of a resin for polymethylmethacrylate prostheses versus one improved with graphene oxide, Lima – Peru, 2023
(Universidad Privada Norbert Wiener, 2023-12-11) Cunya Criollo, Ceneida; Menacho Angeles, Gregorio Lorenzo
The base material for denture prostheses made of PMMA has been used for decades without significant improvements in composition. It has been demonstrated that adding various fillers enhances some properties of acrylic resins. Recent studies have shown that the incorporation of graphene into resin-based dental materials can improve their mechanical properties and even reduce shrinkage during the polymerization process. The objective of this study was to compare the flexural strength values of a polymethyl methacrylate (PMMA) resin versus one enhanced with graphene. Materials and Methods: Thirty heat-cured rectangular samples were fabricated and divided into two groups (n = 15/group): Group 1, PMMA; Group 2, G-PMMA. The samples were subjected to a three-point bending test using a universal testing machine. All specimens were loaded until fracture, and the value in megapascals (MPa) was recorded using software connected to the testing machine to assess the flexural strength. RF data were statistically analyzed using the independent samples t-test to compare the two groups. Results: Compared to the PMMA samples, each G-PMMA sample showed significantly higher RF values (p-value < 0.0001). The PMMA resin showed a flexural strength of 83.15 MPa, while the graphene oxide-enriched resin showed a flexural strength of 93.77 MPa. Conclusions: It is concluded that the graphene-enriched polymer (G-PMMA) proved to be a promising material for prosthetic purposes. This is evidenced by a significant increase in flexural strength.
Acceso abierto
In vitro evaluation of resistance to bending on three types of poles fiberglass of different brands, refor post (ángelus), fiber post (maquira) and medical micro (simplex), Lima 2022
(Universidad Privada Norbert Wiener, 2023-10-03) Vásquez Melgarejo, Leidy; Rojas Ortega, Raúl Antonio
The aim of this research was to compare the flexural strength of three brands of fiberglass posts: Fiber Post (Maquira), Refor Post (Ángelus), and Micro Medica (Simplex). An in vitro, comparative, prospective, and cross-sectional study was conducted with 30 fiberglass posts from three brands: Fiber Post (Maquira), Refor Post (Ángelus), and Micro Medica (Simplex), divided into three subgroups, each consisting of 10 fiberglass posts. Flexural strength was determined using a universal testing machine. Numerical values were collected using a data collection form, and the data was analyzed using the SPSS version 22.0 statistical software. The results showed that the flexural strength of the Refor Post fiberglass post had an average of 887.49 MPa, followed by Fiber Post and Micro Medica with averages of 798.91 MPa and 607.75 MPa, respectively. In conclusion, the Refor Post fiberglass post showed superior resistance compared to the Fiber Post and Micro Medica brands.