Examinando por Materia "Resinas compuestas"

Mostrando 1 - 10 de 10

Acceso abierto

(Universidad Privada Norbert Wiener, 2012) Gálvez Saldaña, Santos; Galvez Ramirez, Carlos Michell
The purpose of this study was to determine the degree of microleakage in composite resins in relation to the cavity preparation surface finish of class II cavities with a right-angle and bevel angle in dental pieces. The in vitro study was experimental, analytical, cross-sectional, prospective, and applicative in nature. Sample: 60 human teeth. Class II cavities were prepared in all, with 30 having a right-angle surface finish and 30 with a bevel-angle surface finish. All samples were filled with composite resin. They were hydrated in 0.9% sodium chloride for one week, and the apices were sealed with acrylic resin. A total of 250 thermocycling cycles at temperatures of 5°C and 55°C were performed. The samples were then immersed in 2% methylene blue for one week. Vertical, horizontal, and coronal cuts were made to evaluate all walls involved in this research, and then observed under an optical microscope at 10x magnification. As a result, in the vertical cut, the three respective degrees of microleakage showed average differences of 30%, 10%, and 20%. In the horizontal cut, the three degrees of microleakage showed average differences of 40%, 10%, and 40%. In the coronal cut, the four degrees of microleakage showed average differences of 20%, 57%, 27%, and 50%, all favoring the bevel-angle restorations. In conclusion, restorations with a bevel-angle cavity preparation surface finish exhibited less microleakage compared to restorations with a right-angle surface finish.
Acceso abierto
Chromatic stability of Palfique lx5 and Filtek z350 composite resins against chicha morada, green tea and Cocacola, in vitro comparative study. Lima 2018
(Universidad Privada Norbert Wiener, 2021-10-23) Misajel Aquino, Carlos Darwin; Girano Castaños, Jorge Alberto
The purpose of this study was to evaluate the color stability of two composite resins exposed to different staining agents. A total of 56 composite resin samples were prepared, with 28 samples of Filtek Z350 and 28 of Palfique LX5. Each resin group was divided into subgroups of 8 samples for each staining substance: chicha, Coca-Cola, and tea, and 4 samples for the control group. Color stability was analyzed using Photoshop software, providing mean values on a grayscale. Data were analyzed using ANOVA and Student's t-test for hypothesis testing of differences. Results: The control group had the highest mean value (144.23±1.67) within the Filtek Z350 resin group, showing a significant difference compared to the staining agent groups (p<0.05). In the Palfique LX5 resin group, the control group and Coca-Cola showed the highest values, significantly differing from the tea (p<0.05) and chicha (p<0.05) groups. Significant differences were found between both resin groups within each staining agent and control group (p<0.05). Conclusion: The effect of pigments on color stability was lower in the control group for Filtek Z350 resin. However, for Palfique LX5 resin, the greatest color effects were observed in the control and Coca-Cola groups, followed by tea, with chicha showing the lowest value.
Acceso abierto
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
Effect of pigmenting beverages on the color stability of composite resins. In vitro study. Lima - Peru. 2021
(Universidad Privada Norbert Wiener, 2021-10-26) Huarcaya Cahuana, Marialejandra; Huamani Caquiamarca, Yuliana Esther
The aim of this research was to determine the effect of pigmented beverages on the color stability of composite resins. Three pigmented beverages (Coca-Cola, red wine, and Red Bull) were used to induce color variation in resins, which were previously molded into discs with a 10mm diameter and 2mm thickness. The initial color of the discs was identified using a visual method and a Vita Classical colorimeter, which has a numerical scale to assess each color tone, ranging from 1 to 16, representing the color scale from B1 to C4. Once the colors of each resin disc were identified, they were separated into groups, and each group was immersed in a container with a different pigmented beverage. The resin discs remained in the containers for 15 days, with the beverage being replaced every 24 hours with an identical one. After 15 days, the resin discs were removed, rinsed with plenty of water, and dried with air before their color was recorded again using the visual method. The data were tabulated and processed using ANOVA statistical analysis. The results showed that the composite resin Tetric N-Flow varied 3.3 ± 1.83 with Coca-Cola, 5 ± 0.0 with Red Bull, and 10.7 ± 2.5 with red wine. The composite resin Tetric N-Ceram varied 0.7 ± 1.83 with Coca-Cola, 1.4 ± 0.84 with Red Bull, and 10.4 ± 2.8 with red wine. Finally, the composite resin Filtek Bulk Fill varied 1.0 ± 0.0 with Coca-Cola, 0.7 ± 0.48 with Red Bull, and 7.8 ± 3.22 with red wine. It was concluded that red wine caused the greatest color variation compared to the other pigmented beverages.
Acceso abierto
Evaluation of the compressive strength of a composite resin inserted directly incrementally versus block insertion and with pre-photopolymerized resin: in vitro study, 2021
(Universidad Privada Norbert Wiener, 2024-06-06) Sobrevilla Alarcón, Anai Yesenia; Arauzo Sinchez, Carlos Javier
One of the major disadvantages of composite resins is their post-photopolymerization shrinkage effect when incremented by more than 2mm in thickness. Due to this, alternative options such as Bulk Fill resins, which allow for an increase of up to 5mm in thickness, and the use of previously photopolymerized resins, are available in the market. Objective: To determine which composite resin insertion technique in proximal cavities has greater compressive strength. Methodology: 45 resin samples were made using acrylic tooth cavities measuring 4x10mm, which were replicated through condensation silicone impressions. The resin samples were from the 3M ESPE brand and divided into three groups: G1: n=15 (Filtek Z350 XT Resin); G2: n=15 (Filtek Bulk Fill Resin); G3: n=15 (Filtek Z350 Resin with Z350 XT Flowable Resin). The resin insertion techniques for G1 used an incremental technique of 2mm thickness; G2 used a block technique with a single 5mm increment; and G3 used a mixed technique with flowable resin and pre-photopolymerized resins. The samples were calibrated and measured using a caliper and periodontal probe. Once the samples were obtained, they were subjected to a compressive strength test using a mechanical testing machine and a Digital Vernier (LG-CMT-5L Mitutoyo-200mm). Results: The compressive strength was 994.88 Newtons using the block technique, 1458.19 Newtons with the incremental technique, and 1241.30 Newtons with the pre-photopolymerized resin technique. There was a significant difference showing higher resistance using the incremental technique compared to the block technique (p<0.05). Conclusion: The incremental resin insertion technique has greater resistance to fracture compared to the block and pre-photopolymerized resin techniques.
Acceso abierto
Evaluation of the efficiency of four finishing and polishing systems for composite resins in relation to surface roughness: In vitro study
(Universidad Privada Norbert Wiener, 2023-10-16) Vilca Vilcayauri, Veronica Yuri; Arauzo Sinchez, Carlos Javier
Objective: To evaluate four finishing and polishing systems for composite resins in relation to surface roughness. Methodology: Tetric N-Ceram Bulk Fill resin (Ivoclar) was used to construct 60 cylinders of 6mm diameter x 2mm height with the monoincremental technique. A celluloid strip and a cover slip were placed on the last layer, followed by 40 seconds of light curing. The cylinders were divided into 4 groups of 15 resin blocks each: Group A, B, C, and D. Each group underwent its first surface roughness measurement with a Digital Rugosimeter (Huatec – SRT 6200), then was immersed in distilled water for 48 hours. After the immersion, the cylinders were polished with the OptraGloss Spiral Wheel (Ivoclar), Diacomp Plus Twist Spiral Wheel (EVE), Jiffy rubber points (Ultradent), and TOR VM polishing discs. A second surface roughness measurement was taken post-polishing. Data were processed using SPSS, with the Shapiro-Wilk normality test. Descriptive statistics (median ± IQR) were analyzed using the Wilcoxon test, Kruskal-Wallis H test with a significance level (p<0.05), and Dunn's test. Results: A significant difference was found between the two measurements, with lower results after 48 hours. The OptraGloss Spiral Wheel polishing system showed a median of 0.66µm, an interquartile range (IQR) of 0.58µm, and a minimum value of 0.24µm. The Diacomp Plus Twist Spiral Wheel system showed a median of 0.45µm, an IQR of 0.38µm, and a minimum value of 0.12µm. The Jiffy rubber points system showed a median of 0.79µm, an IQR of 0.30µm, and a minimum value of 0.45µm. The TOR VM polishing discs system showed a median of 1.52µm, an IQR of 0.32µm, and a minimum value of 0.74µm. Conclusion: The Diacomp Plus Twist Spiral Wheel two-step polishing system achieved the lowest surface roughness, while the TOR VM polishing discs four-step system presented the highest surface roughness.
Acceso abierto
Fracture resistance of microhybrid resins compared to nanohybrid resins: in vitro study, Lima, Peru 2019
(Universidad Privada Norbert Wiener, 2019-11-09) Mamani Jáuregui, Marisol Fiorela; Girano Castaños, Jorge Alberto
Introduction: Nowadays, composite resin restorations are a daily part of dental care, requiring not only excellent aesthetic results but also high fracture resistance under occlusal loads. Objective: To compare the fracture resistance of microhybrid resins and nanohybrid resins. Methodology: Two types of composite resins were used, molded into cylindrical shapes with dimensions of 10 mm in height and 4 mm in diameter. These cylinders were constructed in 2 mm increments, with each increment photo-cured for 20 seconds at 800 nw, and the final layer photo-cured for 40 seconds at 800 nw. The sample size was determined through statistical calculations, comprising 14 resin cylinders of each type. The cylinders were subjected to compression using a universal testing machine, which applied a compressive force at a rate of 0.75 mm/min ± 0.25 mm/min until the resin cylinders fractured. Data were processed using SPSS and analyzed with the Mann-Whitney U test. Results: The fracture resistance of the microhybrid resin was 262.69 ± 42.656 MPa, while that of the nanohybrid resin was 219.45 ± 27.887 MPa. Comparing the two materials revealed that the microhybrid resin had significantly higher fracture resistance than the nanohybrid resin, with a difference of 43.24 MPa (p<0.05). Conclusion: Microhybrid resins exhibit greater fracture resistance compared to nanohybrid resins.
Acceso abierto
Inhibitory effect of chlorhexidine 2% on Metalloproteinases in the adhesion system of composite resins: in vitro study
(Universidad Privada Norbert Wiener, 2024-06-05) Calixto Ostos, Luz Benigna; Llange Arias, Yanet Marlene
The purpose of this study was to determine the inhibitory effect of 2% chlorhexidine on metalloproteinases in the adhesive system of composite resins: an in vitro study. The study used an experimental, quantitative, and analytical design. A formula for independent samples in mean differences was applied, with 15 specimens per group. Additionally, the application of 2% chlorhexidine in dentin bonding was evaluated in terms of tensile strength. The technique used was observation, and data were recorded through a data collection sheet. Calibration of the certified universal testing machine was performed. In the results, it was observed that the average tensile strength for the Adper Single Bond 2-3M adhesive without 2% chlorhexidine was 8.7660, while for the Optibond Universal adhesive without 2% chlorhexidine, it was 10.5553. The average tensile strength for Adper Single Bond 2-3M with 2% chlorhexidine was 10.0707, while for Optibond Universal with 2% chlorhexidine, the average tensile strength was 12.8520. The results of the T-test show that, for both adhesive brands, the average strength was higher when 2% chlorhexidine was used compared to the absence of chlorhexidine, with this difference being statistically significant. It is concluded that there is a significant inhibitory effect of 2% chlorhexidine on metalloproteinases in the adhesive system of composite resins: an in vitro study.
Acceso abierto
Resistance to compression of composite resins at different densities. in vitro study. lima – peru. 2021
(Universidad Privada Norbert Wiener, 2021-11-17) Tantaleán Mendoza, Licet Amparo; Girano Castaños, Jorge Alberto
Objective: To determine the compressive strength of composite resins with different densities. Methodology: Two high-density resins (Filtek Z350XT – 3M Espe and Tetric N Ceram – Ivoclar Vivadent) and two low-density resins (Filtek Flow – 3M Espe and Tetric Flow – Ivoclar Vivadent) were used. These resins were molded into resin cylinders with 10 mm in height and 4 mm in diameter using a plastic mold, where increments of 2 mm were added until the required dimensions were reached. Once the resin cylinders were formed, they were taken to the mechanical testing laboratory for the compression test, where the universal testing machine applied a downward force of 1 mm/min on each resin cylinder until fracture. Data were recorded electronically by the testing equipment. Results: The results showed that the compressive strength of the high-density resins was 218.86 ± 31.18 MPa for Filtek Z350XT and 218.86 ± 31.18 MPa for Tetric N Ceram. The compressive strength of the low-density resins was 225.96 ± 23.32 MPa for Filtek Flow and 186.30 ± 17.3 MPa for Tetric Flow. Conclusion: The low-density resin Filtek Flow exhibited the highest compressive strength, followed by the high-density resins Filtek Z350XT and Tetric N Ceram, and lastly, the low-density resin Tetric Flow.
Acceso abierto
Resistance to fracture of fluid and bulk-type resins in comparison to conventional resins. in vitro study. Lima Perú. 2020.
(Universidad Privada Norbert Wiener, 2020-12-29) Collao Huerta, Oscar Pablo Cesar; Adrianzen Acurio, César Augusto
Objective: To determine the fracture resistance of flowable and bulk-fill resins compared to conventional resins. Methodology: Three types of resins were used: a conventional resin, a flowable resin, and a bulk-fill resin, each shaped into cylinders with dimensions of 8 millimeters in height and 4 millimeters in diameter. The sample size was determined by sample calculation, using 10 resin cylinders of each type, which were subjected to compression by a universal testing machine. This machine applied a compressive force on the resin cylinders at a rate of 1 mm/min of compression until the cylinders fractured. Data processing was carried out using SPSS software with the ANOVA statistical test. Results: It was found that the fracture resistance of conventional resin was 149.879 ± 18.609 Megapascals, the fracture resistance of the flowable resin was 122.994 ± 26.906 Megapascals, and the fracture resistance of the bulk-fill resin was 122.994 ± 26.906 Megapascals. Conclusion: The flowable resin exhibited higher fracture resistance than the conventional resin, and the latter showed greater resistance than the bulk-fill resin.