Examinando por Autor "Baena, Eugenia"

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Effect of Chitosan as a Cross-Linker on Matrix Metalloproteinase Activity and Bond Stability with Different Adhesive Systems
(MDPI, 2020) Baena, Eugenia; Cunha, Sandra R; Maravic, Tatjana; Comba, Allegra; Paganelli, Federica; Alessandri-Bonetti, Giulio; Ceballos, Laura; Tay, Franklin R; Breschi, Lorenzo; Mazzoni, Annalisa
The aim of the present study was to evaluate the effect of 0.1% chitosan (Ch) solution as an additional primer on the mechanical durability and enzymatic activity on dentine using an etch-and-rinse (E&R) adhesive and a universal self-etch (SE) adhesive. Microtensile bond strength and interfacial nanoleakage expression of the bonded interfaces for all adhesives (with or without pretreatment with 0.1% Ch solution for 1 min and air-dried for 5 seconds) were analyzed immediately and after 10,000 thermocycles. Zymograms of protein extracts from human dentine powder incubated with Optibond FL and Scotchbond Universal on untreated or Ch-treated dentine were obtained to examine dentine matrix metalloproteinase (MMP) activities. The use of 0.1% Ch solution as an additional primer in conjunction with the E&R or SE adhesive did not appear to have influenced the immediate bond strength (T0) or bond strength after thermocycling (T1). Zymography showed a reduction in MMP activities only for mineralized and demineralized dentine powder after the application of Ch. Application of 0.1% Ch solution does not increase the longevity of resin-dentine bonds. Nonetheless, the procedure appears to be proficient in reducing dentine MMP activities within groups without adhesive treatments. Further studies are required to comprehend the cross-linking of Ch with dentine collagen.
Endogenous Enzymatic Activity in Dentin Treated with a Chitosan Primer
(MDPI, 2021) Maravic, Tatjana; Baena, Eugenia; Mazzitelli, Claudia; Uros, Josic; Mancuso, Edoardo; Checchi, Vittorio; Generali, Luigi; Ceballos, Laura; Breschi, Lorenzo; Mazzoni, Annalisa
The aim of this study was to evaluate the effect of different concentrations of chitosan polymer on dentinal enzymatic activity by means of gelatin and in situ zymography. Human dentin was frozen and ground in a miller. Dentin powder aliquots were demineralized with phosphoric acid and treated with three different concentrations of lyophilized chitosan polymer (1, 0.5 and 0.1 wt%) dissolved in distilled water. Dentin proteins were extracted from each experimental group and electrophoresed under non-reducing conditions in 10% SDS-PAGE containing fluorescein-labeled gelatin. After 48 h in the incubation buffer at 37 °C, proteolytic activity was registered under long-wave UV light scanner and quantified by using Image J software. Furthermore, additional teeth (n = 4) were prepared for the in situ zymographic analysis in unrestored as well as restored dentin pretreated with the same chitosan primers. The registered enzymatic activity was directly proportional to the chitosan concentration and higher in the restored dentin groups (p < 0.05), except for the 0.1% chitosan primer. Chitosan 0.1% only showed faint expression of enzymatic activity compared to 1% and 0.5% concentrations. Chitosan 0.1% dissolved in water can produce significant reduction in MMPs activity and could possibly contribute to bond strength preservation over time.
Influence of post cure time on the microhardness of self-adhesive resin cements inside the root canal
(Allen Press, 2012) Baena, Eugenia; Fuentes, María Victoria; Garrido, Miguel Ángel; Rodríguez, Jesús
Purpose: To compare the microhardness of several dual-cure, self-adhesive resin cements used to lute fiber posts at 24 hours and seven days after cementation. Methods: Bovine incisors were selected to lute 15 fiber posts that were 12 mm long (FRC Postec Plus size 3, Ivoclar-Vivadent). Five resin cements were tested: Multilink Automix (Ivoclar-Vivadent), without light-curing, and the self-adhesive resin cements Maxcem Elite (Kerr), RelyX Unicem (3M ESPE), G-Cem (GC), and Smartcem 2 (Dentsply), which were light-cured for 40 seconds (LED Bluephase, Ivoclar-Vivadent). Each root was embedded in chemically cured acrylic resin and stored at 37°C for 24 hours. The roots were transversally sectioned into nine specimens that were each 1 mm thick, with three specimens corresponding to each root third. Indentations (100g, 30 seconds) were performed on each section in the resin cement, at 24 hours and seven days after cementation, using a Vickers digital microdurometer (Buehler). Data were analyzed by two-way analysis of variance, Student-Newman-Keuls test, and paired t-test (p<0.05). Results: A significant influence was found (p<0.05) for the resin cement evaluated, the root third, and their interactions on microhardness values at 24 hours and seven days after post cementation. RelyX Unicem and G-Cem exhibited the highest microhardness values, whereas Multilink Automix presented the lowest. All resin cements suffered a decrease in microhardness according to root canal depth, with the exception of G-Cem and Multilink Automix at 24 hours and Smartcem 2 after seven days. After seven days, the evaluated resin cements showed a significant increase in microhardness values, with the exception of Maxcem Elite and Smartcem 2 at the coronal third. Conclusions: Microhardness of the self-adhesive resin cements when used to lute fiber posts was material-dependent and higher values were obtained in the coronal third, revealing their sensitivity to light irradiation. More information regarding the polymerization reaction of these cements is warranted. According to the current results, microhardness values were significantly higher one week after post luting.
Influence of repair procedure on composite-to-composite microtensile bond strength
(Mosher & Linder Inc, 2015) Baena, Eugenia; Vignolo, Valeria; Fuentes, María Victoria; Ceballos, Laura
Purpose: To investigate the effect of different repair procedures and storage time on microtensile bond strength (μTBS) of a resin composite to an older one from a simulated previous restoration. Methods: Composite disks were made by layering 2 mm-thick increments of a nanohybrid composite (Grandio) shade A1 in a Teflon mold (4 x 8 mm). Afterwards, they were light-cured and stored (37 degrees C/7 days) in a saline solution. Specimens were randomly divided into groups according to the surface treatment applied: (1) Composite surface was roughened with a bur (Cimara) and Solobond Plus adhesive was applied; (2) Sandblasting with 27 μm aluminum oxide particles (KaVo Rondoflex), and adhesive application; (3) Air-abrasion with 30 μm alumina particles coated with silica (CoJet Sand), silane (Monobond-S) and adhesive application; (4) Negative control group with only adhesive application. Afterwards, Grandio composite (shade A3.5) was packed incrementally on the treated surface obtaining another disk (4 x 8 mm). Repaired blocks were stored (24 hours or 6 months) and afterwards μTBS test was performed and failure mode was evaluated. Also, beams obtained from 8 mm-high composite blocks without any surface treatment were immediately submitted to μTBS test to determine Grandio composite cohesive bond strength (positive control group). Data were analyzed using ANOVA and Tukey's test (P < 0.05). Results: The repair procedure affected μTBS values (P < 0.001) while neither storage time nor interactions did (P > 0.05). All repair procedures achieved bond strength values higher than the negative control group but they did not reach the composite's cohesive bond strength. The overall conclusion was that an increased superficial roughness by means of a bur, silica coating or alumina sandblasting improved μTBS of the repaired composite and bond strength remained stable after 6 months.
Influence of root dentin treatment on the push-out bond strength of fiber posts
(Springer, 2016) Baena, Eugenia; Flores, A; Ceballos, L
The aim of the present study was to assess whether different dentin conditioning protocols with different acids [phosphoric acid, ethylene diamine tetra acetic acid (EDTA), and polyacrylic acid (PAA)] influence the bond strength of fiber posts along the radicular depth when luted with self-adhesive resin cement. Twenty single-rooted teeth were randomly divided into four experimental groups (n = 5) according to dentin treatment: Group 1: no treatment; Group 2: etching with 35 % phosphoric acid for 10 s; Group 3: 17 % EDTA application for 60 s; and Group 4: conditioning with 25 % PAA for 30 s. RelyX Fiber Posts were luted with the self-adhesive resin cement RelyX Unicem 2 Automix (3M ESPE). Roots were transversally sectioned into nine 1-mm thick specimens, three corresponding to each root third and a push-out test was performed. Data were analyzed by two-way ANOVA and Tukey test (p < 0.05). Failure mode was determined and specimens with representative failures for each group were observed under scanning electron microscopy. According to the results, dentin treatment influenced the bond strength (p < 0.001), whereas the root third did not (p > 0.05). Fiber posts luted after treating dentin with phosphoric acid, and PAA exhibited the highest push-out bond strength values, while the lowest were obtained after EDTA application. Intermediate results were obtained when dentin was not conditioned. In conclusion, the bond strength of the self-adhesive resin cement RelyX Unicem 2 improves when root dentin is treated with 35 % phosphoric acid or 25 % PAA, before fiber posts luting irrespective of the root depth.
One-year clinical performance of lithium disilicate versus resin composite CAD/CAM onlays
(Springer, 2020) Souza, Joana; Fuentes, Maria Victoria; Baena, Eugenia; Ceballos, Laura
To compare the 1-year clinical performance of lithium disilicate and resin composite CAD/CAM onlay restorations. Twenty patients that required two restorations in posterior teeth, with at least one cusp to be covered, received two onlays. One was made with IPS e.max CAD (Ivoclar-Vivadent) and the other with Lava Ultimate (3M Oral Care). Two blind observers evaluated the restorations at baseline and 1 year after the onlays were cemented, according to FDI criteria. At each recall, digital photographs, bite-wing radiographs and impressions of the restorations were taken for SEM evaluation of the interface. Results were analyzed by Mann-Whitney U and Wilcoxon tests (p < 0.05). At baseline and in the 1-year recall, both CAD/CAM materials exhibited excellent results in most criteria with similar esthetic, functional and biological properties (p > 0.05). However, deterioration in surface lustre (p = 0.020) and color match/translucency (p = 0.039) were detected for IPS e.max CAD onlays after 1-year. Under SEM evaluation, there were no statistically differences in micromorphological criteria at baseline nor after a year between IPS e.max CAD and Lava Ultimate onlays. Conclusion: After 1 year of clinical service IPS e.max CAD and Lava Ultimate onlays showed a similar clinical performance that needs to be confirmed in long-term evaluations.