Examinando por Autor "Menacho Angeles, Gregorio Lorenzo"

Mostrando 1 - 7 de 7

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Adhesive strength of fiberglass bolts using two resinous cement systems. in vitro study. Lima Peru. 2021.
(Universidad Privada Norbert Wiener, 2022-11-12) Muñoz Rodríguez, Senith Aide; Menacho Angeles, Gregorio Lorenzo
Objective: To compare the adhesive resistance of fiberglass posts using two resin cement systems. Methodology: 7 teeth were used for each cement type (Relyx U200 and RelyX Ultimate). A transverse cut was made at 2 mm from the cement-enamel junction on each tooth. The root canal treatment was then performed. For cementing with Relyx Ultimate, 37% phosphoric acid and Scotchbond universal adhesive were used beforehand, while for Relyx U200 cementing, the cement was applied directly. After cementing the fiberglass post, all teeth were cut into 1 mm thick discs, resulting in 6 discs. These root portion discs were taken to the DHL mechanical testing laboratory, where they underwent push-out testing to measure adhesive strength using a universal testing machine. Results: The adhesive strength of the fiberglass posts with Relyx Ultimate resin cement was 37 ± 14.59 Mpa in the cervical portion, 32.61 ± 8.44 Mpa in the middle portion, and 34.29 ± 9.13 Mpa in the apical portion. For Relyx U200 cement, the values were 34.05 ± 9.23 Mpa in the cervical portion, 38.43 ± 14.29 Mpa in the middle portion, and 30.15 ± 15.17 Mpa in the apical portion. Conclusion: No significant difference was found in the adhesive strength of fiberglass posts using the resin cement systems Relyx U200 and RelyX Ultimate in all three root thirds.
Acceso abierto
comparison between the perception of dentists and patients on the factors that affect the aesthetics of the smile in a private dentistry center, 2023
(Universidad Privada Norbert Wiener, 2023-10-28) Garcilazo Fernández, Danitza Alexandra; Menacho Angeles, Gregorio Lorenzo
In recent years, one of the most requested treatments by patients in dental consultations has been aesthetic dental treatments in the pursuit of a healthy and youthful smile. Dental professionals must consider the different perceptions of what is considered aesthetic in various population groups due to the subjective factors involved in their assessment. Therefore, the general objective of this research was to compare the perceptions of dentists and patients regarding the factors affecting the aesthetics of the smile in a private dental center, 2023. Materials and Methods: The sample consisted of 15 dentists and 45 patients from a dental center. The study technique was a survey, and the measurement instrument was a questionnaire with 3 questions where 9 smile photographs were evaluated, with 3 photographs for each component of the smile being considered. These photographs were modified using Photoshop. The smile components evaluated were gingival contour, lip line, and dental proportion, which were assessed on an analog visual scale (VAS) with 5 levels of attractiveness. Results: It was found that the gingival contour perceived as attractive by patients and dentists was photograph 1, with 37.8% and 40.0%, respectively. Regarding the lip line, the smile perceived as more aesthetic was photograph 5, with 37.8% and 40%, respectively. Regarding dental proportion, photograph 8 received an aesthetic perception rating of 17.8% and 26.7%, respectively, indicating similar perceptions between the evaluators. Conclusion: It was concluded that there is no difference in aesthetic perception when evaluating smile factors between dentists and patients at a private dental center.
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
Effect of 1.23% acidulated fluorphosphate and 2% sodium fluoride on the fracture resistance of resin-modified glass ionomer
(Universidad Privada Norbert Wiener, 2024-06-14) Canales Rios, Alexandra Yveth; Menacho Angeles, Gregorio Lorenzo
The methodological design was observational, comparative, and cross-sectional. A total of 45 samples of glass ionomer discs with a resin composition from a commercial brand (Vitremer) were used, with a diameter of 2 mm and a thickness of 6 mm, distributed into groups: for the first group, 15 discs of ionomer with a resin composition were treated with 0.05 ml of 1.23% fluoride from a commercial brand (Maquira); for the second group, 15 discs of ionomer with a resin composition were treated with 0.05 ml of 2% fluoride from a commercial brand (Maquira), and both groups were treated with fluoride for 4 minutes, followed by washing and drying. The third group consisted of 15 discs of ionomer with resin composition to which no fluoride was applied. The results of the Tukey HSD multiple comparison test showed a statistically significant difference (p=0.000) between the resistance of the acidulated phosphate fluoride group at 1.23% (mean=21.36360 Kg/mm²) and the control group (mean=25.36360 Kg/mm²). In conclusion, the average resistance of the fluoride group at 1.23% concentration and the fluoride group at 2% concentration did not show statistically significant differences (p=0.198).
Acceso abierto
Efficacy of two apex locators in determining the working length. In vitro study. Lima, Peru 2021
(Universidad Privada Norbert Wiener, 2023-04-19) Cutisaca Cayllahua, Mijail; Menacho Angeles, Gregorio Lorenzo
The efficacy of two apex locators in determining the working length was assessed using 17 single-root natural teeth. The teeth were subjected to coronal access and insertion of Nitiflex K-files up to the root canal limit, with the measurement recorded in millimeters. Subsequently, two apex locators (I-root and Woodpex III) were used to determine the same working length. For the use of these devices, the oral environment was simulated by placing the dental pieces in an alginate mold, where a lip clip was also placed, and the electrode was connected to the endodontic file, closing the circuit. The data generated were recorded and tabulated using the Student's T-test and one-way ANOVA statistical tests. As a result, the actual working length of the dental pieces was 21.40 ± 2.23 mm, while the working length of the dental pieces evaluated with the I-Root and Woodpex III apex locators was 21.15 ± 2.34 mm and 21.28 ± 2.31 mm, respectively. In conclusion, no statistical disparity was found between the results (p > 0.05), with the largest difference between the actual and electronic working lengths being 0.25 mm.
Acceso abierto
Evaluation of aesthetic perceptions and social judgments about different dental enamel opacities in adolescents from the Peruvian jungle.
(Universidad Privada Norbert Wiener, 2022-06-11) Ruiz Arutaype, Yessenia Odalis; Menacho Angeles, Gregorio Lorenzo
Objective: To determine the aesthetic perception and social judgment of different enamel opacities in adolescents from the Peruvian Amazon. Materials and Methods: An observational, cross-sectional, and descriptive study was conducted, with a sample of 134 adolescents with an average age of 13.67 ± 1.58 years. A twelve-question questionnaire was used to measure aesthetic perception and social judgment of different enamel opacities, which was validated by expert judgment. The data were analyzed using the SPSS v.25 statistical package with a 5% significance level. Results: It was observed that the enamel opacity type with the highest score in positive social characteristics was unilateral yellowish opacity with structure loss, with an average of 2.23 ± 0.76, and bilateral yellowish opacity with 2.19 ± 0.91. On the other hand, those with the highest score in negative social characteristics were unilateral yellowish opacity with structure loss with -1.85 ± 0.89 and unilateral white opacity with -1.08 ± 0.99. In the overall social judgment score, the highest score was bilateral yellowish opacity with structure loss, with 1.27 ± 1.56, followed by bilateral yellowish opacity with 1.23 ± 1.30. Conclusion: When relating social judgments to different aesthetic perceptions of enamel opacities, a statistically significant difference was obtained in the aesthetic perception of the photograph with bilateral yellowish opacity with structure loss and gender.
Acceso abierto
Location of the gingival zenith with respect to the vertical axis of the upper anterior teeth; and lateral incisors in relation to the gingival zeniths of the adjacent proximal teeth in patients treated at the San Marcos advanced dentistry clinic. Lima, 2022
(Universidad Privada Norbert Wiener, 2024-06-11) Herrera Poma, Pablo Antonio; Menacho Angeles, Gregorio Lorenzo
The objective of this study was to determine the location of the gingival zenith in relation to the vertical axis of the upper anterior teeth and the lateral incisors in relation to the gingival zeniths of the adjacent proximal teeth. Methodology: A total of 44 patients treated at the Advanced Dentistry Clinic San Marcos between October and November 2022 were evaluated. These patients were asked to participate in the study by signing an informed consent form. With their authorization, an alginate study model was taken, which was immediately poured with dental stone. The gingival zenith analysis was performed on the study model, where various tracings were made to identify the gingival zenith, its location, and its displacement in millimeters from the vertical axis of the dental piece, as well as its position relative to the adjacent teeth. Results: The location of the gingival zenith relative to the vertical axis for the upper central incisors was 1.01 mm and 0.99 mm, while for the lateral incisors, it was 0.70 mm and 0.80 mm, and for the canines, it was 0.50 mm and 0.48 mm. Additionally, the right and left lateral incisors showed a distance of 0.90 mm and 0.85 mm from the tangential line formed between the zeniths of the central incisors and canines. Conclusion: The gingival zeniths of the right and left central incisors, lateral incisors, and canines were mostly found towards the distal, while the lateral incisors were mostly found towards the coronal of the tangential line formed by the zeniths of the adjacent teeth.