Examinando por Materia "Ácido fosfórico"

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Acceso abierto
Change of dental coloration in pigmented bovine specimens using mechanical microabrasion with 18% hydrochloric acid and 37% phosphoric acid techniques: comparative in vitro study, Lima 2018
(Universidad Privada Norbert Wiener, 2018-12-06) Herrera Pastor, Carla Vanesa; Reynafarje Reyna, Julio César
Enamel microabrasion is an effective and conservative treatment for the removal of stains or atypical pigments from the enamel surface. After a thorough review, it is known that there are two acids, one more commonly used than the other. But how effective are they when compared? Objective: To determine which technique produces a greater change in dental coloration in pigmented bovine teeth, using mechanical microabrasion with hydrochloric acid at 18% (HCL18%) and phosphoric acid at 37% (H3PO4 37%). Materials and Methods: Experimental, in vitro study. A total of 74 bovine permanent teeth were used, followed by pigmentation with ground and instant coffee for a period of 48 hours. The samples were randomly divided into two groups (n=34), based on the acid used: Group 1: HCL18% + pumice stone, applied with a prophylactic brush; Group 2: H3PO4 37% + pumice stone, using a rubber cup for prophylaxis. All samples received 5 applications of 10 seconds each, followed by 10 seconds of rinsing. The color change was measured using a visual color guide, VITA Toothguide 3D-MASTER, before the treatment, after the 1st, 3rd, and 5th applications. Results: Statistically, mechanical microabrasion with HCL18% generated a greater change in color in pigmented bovine teeth compared to H3PO4 37%, with p = 0.01 < 0.05. There was also a color change in the teeth treated with H3PO4 37% after the 1st, 3rd, and 5th applications (p = 0.000). Conclusion: Both techniques showed effectiveness in terms of dental color change.
Acceso abierto
Shear strength comparing three pre-etching agents in tooth enamel in relation to adhesion, in vitro study, Lima-2022
(Universidad Privada Norbert Wiener, 2023-09-30) Alejos Nureña, Paola Rosario; Rojas Ortega, Raúl Antonio
The objective of this study was to 'Determine the shear strength of three enamel pre-etching agents in relation to adhesion.' An in vitro, pure experimental, cross-sectional, prospective, and comparative study was developed. The sample consisted of 30 dental pieces, divided into three groups: Group A: 10 samples with 37% phosphoric acid applied for 15 seconds; Group B: 10 samples with 5.25% sodium hypochlorite applied for 60 seconds; Group C: 10 samples with 5.25% sodium hypochlorite applied for 60 seconds + 37% phosphoric acid applied for 15 seconds. The samples were then subjected to the HTL certified universal testing machine, calibrated and validated, which provides approximately 95% confidence level. According to the ANOVA parametric test, significant differences (p < 0.05) were observed between the three groups. It was found that between 37% phosphoric acid for 15 seconds and 5.25% NaClO for 1 minute, a significant difference (p < 0.05) exists; between 37% phosphoric acid for 15 seconds and 5.25% NaClO + 37% phosphoric acid for 15 seconds, no significant difference (p > 0.05) was found; and between 5.25% NaClO for 1 minute and 5.25% NaClO + 37% phosphoric acid for 15 seconds, significant differences (p < 0.05) were observed. Conclusion: Shear strength exists in enamel deproteinized with 5.25% NaClO prior to etching with 37% phosphoric acid, resulting in a higher average of 33.489, median of 32.44, variance of 48.854, standard deviation of 6.9896, a minimum value of 22.01, and a maximum value of 46.61, demonstrating the increase in adhesion pattern.