Examinando por Materia "Flexural strength"

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Comparative study of the flexural resistance of photocured Bulk Fill composite resins with two Led Photoactivation units
(Universidad Privada Norbert Wiener, 2022-01-07) Melendrez Camizan, Hilda; Rojas Ortega, Raúl Antonio
The present research titled "Comparative Study of Flexural Strength of Bulk Fill Composite Resins Photocured with Two LED Curing Units" aimed to compare the flexural strength of bulk fill composite resins when photocured with LED curing units. A hypothetical-deductive research method was used with a quantitative approach, applied, cross-sectional, prospective, experimental, and post-test experimental design. The sample consisted of 80 bulk fill resin bodies in bar form (2mm x 2mm x 10mm), from the Z350 XT, One Bulk Fill, Tetric Bulk Fill, Aura Bulk Fill, and Opus Bulk Fill groups, divided into groups of 16, 8 of which were photocured with Elipar™ DeepCure-L - 3M and the other 8 with Woodpecker® iLED. The results showed that the photoactivation with Elipar™ DeepCure-L- 3M presented an average of 148.2993 MPa, and the photoactivation with Woodpecker® iLED presented an average of 152.17172 MPa. In the hypothesis test, Levene's test was used for variance equality, and a p-value of 0.596 was obtained, which is p>0.05. Therefore, it was concluded that there is no significant difference between the flexural strengths of bulk fill composite resins when photocured with LED curing units.
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
Comparison of the flexural strength of a nanohybrid resin and a Bulk Fill type resin. In Vitro Study. Lima - Peru 2021.
(Universidad Privada Norbert Wiener, 2022-05-05) Cruz Huaman, Iris; Vásquez Rodrigo, Hernán
Two resins were used, a microhybrid (Filtek™ Z250XT – 3M Espe) and a bulk fill type (Filtek™ Z250XT – 3M Espe). These resins were used to form resin bars of 60 mm in length, 10 mm in width, and 2 and 4 mm in thickness. The resin bars were formed with the help of two metal molds of the specified dimensions, differing only in thickness, one mold with 2 mm thickness and the other with 4 mm thickness. In the 2 mm thickness mold, the resin bars were formed with 2 mm increments until the resin bar was completed, while in the 4 mm thickness mold, the resin bars were formed with 4 mm increments. Once the resin bars were formed, they were taken to the mechanical testing laboratory for the flexural strength test, where each resin bar was individually placed on a metal structure with two equidistant supports at the base. A metal piece was then lowered at the center of the resin bar to test its flexion under compressive load, advancing at 1 mm/min until the material fractured, with data recorded electronically by the same equipment. Results: The results showed that the flexural strength of the nanohybrid resin with 4 mm increments was 113.89 ± 27.94 Megapascals. This was followed by the bulk fill resin with 2 mm increments (109.69 ± 75.60 Megapascals), then the nanohybrid resin with 2 mm increments (93.87 ± 15.97 Megapascals), and lastly, the bulk fill resin with 4 mm increments (75.60 ± 5.88 Megapascals). Conclusion: The highest flexural strength of the resins was found in the microhybrid resin Filtek™ Z250XT with 4 mm increments, followed by the flexural strength of the Filtek™ Bulk Fill resin with 2 mm increments. This was followed by the flexural strength of the Filtek™ Z250XT resin with 2 mm increments, and lastly, the Filtek™ Bulk Fill resin with 4 mm increments.
Acceso abierto
Flexural resistance in fiberglass poles with different structural form, in vitro - Lima study 2021
(Universidad Privada Norbert Wiener, 2023-06-21) Vilca Huallpa, Dayana Pamela; Guevara Sotomayor, Juan César
The objective of this research was to compare the flexural strength between the fiberglass posts White Post DC - Fgm #0.5, Reforpost - Angelus #1, and Endodontic Over Post - Over Fibers #1, in an in vitro study conducted in Lima, 2021. This was a descriptive study with a quantitative approach, experimental design, and a cross-sectional comparative approach. The sample consisted of 30 fiberglass posts, divided into three groups of 10 units each: group 1: Reforpost, group 2: Whitepost, and group 3: Over Post. The posts were digitally calibrated according to ISO 14125 standards, and flexural strength tests were performed using the Microtensile OM100 semi-universal testing machine at a crosshead speed of 0.8mm/min and a load angle of 90°. The results showed that the average flexural strength of the Whitepost - FGM fiberglass was 758.45 Mpa, Reforpost - Angelus fiberglass was 1066.26 Mpa, and Over Post - Over Fibers fiberglass was 961.82 Mpa, with a p-value > 0.05. Conclusion: Comparing the flexural strength of the fiberglass posts White Post DC - Fgm #0.5, Reforpost - Angelus #1, and Endodontic Over Post - Over Fibers #1 provides sufficient statistical evidence to conclude that they are different. It is noteworthy that Reforpost fiberglass had the highest flexural strength.
Acceso abierto
Flexural resistance of Ivoclar Vivadent Triplex Hot heat-cured acrylic using two polymerisation methods for the manufacture of dental prostheses: in vitro study. Lima, Peru 2021
(Universidad Privada Norbert Wiener, 2023-11-24) Lazarte Melgarejo, Claudio Gabriel; Adrianzen Acurio, César Augusto
Objective: To determine the flexural strength of Ivoclar Vivadent Triplex Hot thermocured acrylic using two polymerization methods for the fabrication of dental prostheses. Methodology: A total of 24 Triplex Hot acrylic bars were used, divided into 2 groups. The first group consisted of 12 bars of acrylic made by the conventional heat method, and the second group consisted of 12 bars made using the microwave method. A constant downward force of 1 mm/min was applied at the center of the length of each acrylic bar until fracture occurred. Results: The flexural strength of Ivoclar Vivadent Triplex Hot thermocured acrylic using the conventional polymerization method was 100.08 ± 4.60 MPa, while the flexural strength using the microwave polymerization method was 103.28 ± 3.28 MPa. Conclusion: No statistical disparity was found between the results (p > 0.05), with the largest difference in flexural strength between the conventional polymerization method and the microwave method being 3.2 MPa.
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.