Papers by Beatriz Togoro Ferreira da Silva
European Journal of Oral Sciences
This study investigated the effect of irradiation with an erbium-doped yttrium aluminium garnet (... more This study investigated the effect of irradiation with an erbium-doped yttrium aluminium garnet (Er:YAG) laser and coating with silica on the surface characteristics, bond strength, and flexural strength of dental zirconia. Three hundred and forty-three standard zirconia specimens were created, and 49 were assigned to each of seven surface treatment groups: (i) no treatment; Er:YAG laser (80 mJ/2 Hz) with pulse widths of 50 μs (ii), 100 μs (iii), 300 μs (iv), or 600 μs (v); or tribochemical silica coating at the partially sintered stage (vi) or after sintering was complete (vii). All specimens were sintered after the surface treatments, except for the group in which specimens were sintered before treatment. The study outcomes were roughness, surface loss, microshear bond strength (μSBS), and biaxial flexural strength (BFS). Mean roughness and surface loss values were significantly higher in specimens from irradiated groups than in those from silica-coated groups. Regarding μSBS, after aging, specimens from all experimental groups presented very low and similar μSBS values, irrespective of the surface treatment. Silica coating after sintering yielded the highest BFS (1149.5 ± 167.6 MPa), while coating partially sintered specimens with silica resulted a BFS (826.9 ± 60.9 MPa) similar to that of the untreated control group (794.9 ± 101.7 MPa). Laser treatments, irrespective of pulse width used, significantly decreased the BFS. In the group treated with laser at 300 μs pulse width, specimens exhibited the lowest BFS value (514.1 ± 71.5 MPa). Adhesion to zirconia was not stable after aging, regardless of the surface treatment implemented.
Silva BTF. Effect of temporal width pulse of Er:YAG laser on surface characteristics, bond streng... more Silva BTF. Effect of temporal width pulse of Er:YAG laser on surface characteristics, bond strength and mechanical properties of zirconia [thesis].
Journal of Esthetic and Restorative Dentistry
PURPOSE This study aims to evaluate the effect of erosive, abrasive, and erosive/abrasive challen... more PURPOSE This study aims to evaluate the effect of erosive, abrasive, and erosive/abrasive challenges on the glaze layer of ceramic materials. METHODS Ninety-five samples of monolithic zirconia (MZ) (LuxaCam Zircon HT-Plus) and lithium disilicate (LD) (IPS e.max CAD) were divided according to the response variables: Surface roughness and surface loss (n = 10), evaluated with optical profilometry; surface topography, with scanning electron microscopy SEM (n = 3); and biofilm deposition, with microbiological assay (n = 5). The evaluations were performed in three different time evaluations: (a) Sintered, (b) Glaze, and (c) Challenge (Erosion, Abrasion, and Erosion/Abrasion). Erosion consisted in immersing specimens in HCl solution, abrasion was performed with brushing machine, and erosion/abrasion consisted of a combination of the two previous protocols. Data were analyzed with parametric tests (P < 0.05). RESULTS MZ glaze layer presented significantly higher surface roughness (P = 0.00), surface loss (P = 0.03), and biofilm deposition (P = 0.00) than LD. Abrasion and erosion/abrasion showed similar outcomes, generating significantly higher surface roughness (P = 0.00), surface loss (P = 0.00), and biofilm deposition (P = 0.01) than erosion. CONCLUSIONS Glaze layer properties were altered by the challenges, with abrasion and erosion/abrasion generating higher surface roughness, surface loss, and biofilm deposition than erosion. A significant correlation was found between the surface roughness and biofilm deposition. CLINICAL SIGNIFICANCE The glaze layer is susceptible to challenges, especially to abrasion and erosion/abrasion, which generated greater surface roughness and surface loss than erosion. The greater surface roughness lead to a greater biofilm deposition on the glaze layer.
Clinical and Laboratorial Research in Dentistry
Objetivo: Analisar efeitos de diferentes envelhecimentos sobre a rugosidade e a cor de cimentos d... more Objetivo: Analisar efeitos de diferentes envelhecimentos sobre a rugosidade e a cor de cimentos de ionômero de vidro (CIV) encapsulados. Materiais e métodos: Foram testados dois cimentos de ionômero de vidro [convencional/ Self Cure (SC) e resino modificado/Light Cure (LC)] e envelhecimentos [(baseline, pós-ciclagem térmica e pós- -ciclagem térmica + armazenamento por sete meses)]. 52 discos (n = 13) foram confeccionados. A cor foi avaliada por dois espectrofotômetros (VITA Easyshade e Konica Minolta CE3700A), e a rugosidade pelo perfilômetro óptico (Proscan 2100, Scantron). Resultados: ANOVA dois fatores e teste de Tukey (p < 0,05) foram realizados. Os CIVs apresentaram diferenças estatisticamente significantes entre si (p < 0,05) para rugosidade (SC = 0,202 μm e LC = 0,241), os envelhecimentos alteraram significativamente a rugosidade baseline = 0,278 μm, ciclado = 0,220 μm e ciclado-armazenado = 0,167 μm, e para cor (SC ΔE = 3,89 e o LC ΔE = 4,94). Para ΔL*, Δa*, Δb* houve ...
Brazilian Dental Science
Resumo Objetivo: Este estudo investigou a influência de diferentes tratamentos de superfície na e... more Resumo Objetivo: Este estudo investigou a influência de diferentes tratamentos de superfície na energia de superfície, rugosidade e resistência de união da zircônia. Material e Métodos: Quarenta e oito fatias de zircônia tetragonal policristalina estabilizada por ítria (Y-TZP-VITA In-Ceram® YZ for inLab®) (6,4 x 3,2 x 1,6 mm) foram divididas em 3 grupos de acordo com o tratamento de superfície (n = 16): YTZP_controle sem tratamento; YTZP_plasma-tratamento de superfície com plasma de oxigênio não térmico; YTZP_primer-aplicação de um primer cerâmico. A energia da superfície (n = 6) foi medida com o auxilio de um goniômetro; e a rugosidade superficial (n = 10) foi analisada com um perfilômetro 3D. Nos mesmos espécimes da rugosidade, prolongamentos de cimento resinoso (PANAVIA V5-Kuraray Noritake Dental) foram construídos inserindo o cimento em micro túbulos de silicone (1mm de diâmetro interno de X 1 mm de comprimento). O teste de microcisalhamento foi realizado após 24h. Os dados foram analisados estatisticamente ANOVA um fator e teste auxiliar de Tukey (p < 0,05). Resultados: Os espécimes tratados com plasma de oxigênio apresentaram maiores valores de energia de superficie (p = 0,00) e resistência de união estatisticamente significante (p = 0,00) quando comparados aos grupos controle e do primer. A análise de rugosidade (p = 0,897) não detectou diferença estatística entre os grupos testados. Conclusão: O plasma não térmico pode ser uma alternativa para o tratamento de superfície de zircônia antes da cimentação, pois aumentou a resistência de união ao microcilsalhamento e proporcionou maior energia superficial sem afetar a rugosidade da superfície.
Silva BTF. Effect of Er:YAG laser pulse widths on pre-sintered zirconia [dissertation].
Brazilian Oral Research
Bonding plays a major role in dentistry nowadays. Dental adhesives are used in association with c... more Bonding plays a major role in dentistry nowadays. Dental adhesives are used in association with composites to solve many restorative issues. However, the wide variety of bonding agents currently available makes it difficult for clinicians to choose the best alternative in terms of material and technique, especially when different clinical situations are considered. Moreover, although bonding agents allow for a more conservative restorative approach, achieving a durable adhesive interface remains a matter of concern, and this mainly due to degradation of the bonding complex in the challenging oral environment. This review aims to present strategies that are being used or those still in development which may help to prevent degradation. It is fundamental that professionals are aware of these strategies to counteract degradation as much as possible. None of them are efficient to completely solve this problem, but they certainly represent reasonable alternatives to increase the lifetime of adhesive restorations.
Journal of Materials Science, 2016
Abstract This study evaluated the effects of different Er:YAG laser pulse width protocols on surf... more Abstract This study evaluated the effects of different Er:YAG laser pulse width protocols on surface roughness, loss of volume of the material, and the step height formed of pre-sintered yttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) by three-dimensional profilometric assessment. Blocks of pre-sintered Y-TZP were cut providing 63 standard 5-mm-thick samples which were divided by surface treatment, as follows (n = 9): G50 (100 mJ/10 Hz/1 W-50 μs); G100 (−100 μs); G300 (−300 μs); G600 (−600 μs); G1000 (−1000 μs); GTC (tribochemical silica coating); and GNC (untreated). After treated or not, samples were sintered according to the manufacturer’s recommendations. Roughness, volume loss and step height were analyzed by 3D profilometric assessment with confocal laser microscopy. ANOVA and Tukey’s test (p < 0.05) detected that irradiated groups showed increased roughness in the groups G50, G100, G300, and G600 when compared to GTC and GNC groups. The G1000 group showed a completely flat and unfavorable surface for retention. The groups G50, G100, and G300 showed great loss of volume and the step height formed, which can lead to a gap on the crowns. In G600 was observed satisfactory roughness with little loss of volume and the step height formed similar to GTC. Irrespective of laser protocol, any of the specimens showed the presence of cracks. It is suggested that the pulse width 600 μs (G600) is the most suitable pulse width protocol as an alternative surface treatment, promoting micro-retention, with little loss of volume of material, comparable to silica coating treatment.
Clinical and Laboratorial Research in Dentistry, 2014
O objetivo deste estudo foi avaliar o conteúdo mineral do esmalte submetido ao clareamento dental... more O objetivo deste estudo foi avaliar o conteúdo mineral do esmalte submetido ao clareamento dental e a infl uência do tempo de espera após o tratamento clareador no selamento marginal de restaurações classe V em resina composta. Neste estudo, a variável de resposta selamento marginal foi avaliada por metodologia de microinfi ltração, segundo o fator de variação tempo de espera para o procedimento restaurador, imediatamente após, e 7 e 14 dias após o tratamento clareador. O conteúdo mineral foi avaliado pelo método QLF (quantitative light-induced fl uorescence). As unidades experimentais foram compostas por 40 coroas de incisivos bovinos que foram distribuídas entre os 4 grupos experimentais (n = 10): G1, dentes bovinos não clareados (controle); G2, dentes clareados e imediatamente restaurados; G3, dentes clareados e restaurados após 7 dias; G4, dentes clareados e restaurados após 14 dias. Os escores de infi ltração foram analisados por 3 examinadores previamente calibrados. Não foi observada diferença estatística entre os grupos com relação à alteração mineral do substrato clareado (ANOVA para mensurações repetidas, p = 0,2130) e ao grau de microinfi ltração marginal (Friedman, p = 0,2551). Pôde-se concluir que o protocolo clareador utilizado é seguro por não acarretar alterações minerais do esmalte clareado, e que o tempo de espera para a realização de procedimentos adesivos não interferiu no selamento marginal de restaurações em resina composta. Clareamento Dental; Resinas Compostas; Infi ltração Dentária. Importance of post-bleaching time interval on the marginal seal of class V composite resin restorations • The aim of this study was to evaluate changes in mineral content of bleached enamel and the infl uence of post-bleaching time interval on the marginal seal of class V composite restorations. Forty bovine incisors were restored using Magic Bond adhesive and Fill NT Premium composite according to the manufacturer's instructions. The teeth were randomly divided into 4 experimental groups (n = 10): G1, not bleached (control); G2, bleached and immediately restored; G3, bleached and restored after 7 days; G4, bleached and restored after 14 days. The mineral content was evaluated by QLF (quantitative light-induced fl uorescence). The microleakeage scores were analyzed by 3 calibrated examiners. There was no statistical difference between the groups regarding change of the bleached mineral substrate (repeated measures ANOVA, p = 0.2130) and the microleakage scores (Friedman, p = 0.2551). It was concluded that the bleaching protocol used is safe because it does not cause mineral changes in the bleached enamel, and that the post-bleaching time interval observed before performing adhesive procedures did not affect the marginal seal of composite resin restorations. Tooth Bleaching; Composite Resins; Dental Leakeage.
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Papers by Beatriz Togoro Ferreira da Silva