The influence of LED irradiance on the degree of conversion of resin luting agents under translucent zirconia.

This study aimed to evaluate the effect of different LED irradiance levels on the degree of conversion (DC) of dual-cured resin luting agents photocured through a high-translucency zirconia disc. Fifty-four disc specimens (approximately 0.1 × 6.0 × 6.0 mm) were prepared using 3 dual-cured resin luting agents (Panavia F 2.0, RelyX Unicem 2 Automix, and Calibra). Eighteen groups (n = 3) were evaluated. Test specimens were photocured through a 0.7 × 10.0-mm, high-translucency zirconia disc for 20 seconds using 1 of 3 different LED irradiances (mean output of 855, 1330, or 1750 mW/cm2 after 3 consecutive measurements with an LED radiometer). Specimens photocured directly, without a zirconia disc, were used as controls. Microattenuated total reflectance/Fourier-transform infrared spectroscopy was used to evaluate the extent of polymerization of all specimens prior to curing (baseline) and 24 hours after curing. Data were analyzed by 3-way analysis of variance and Tukey multiple comparisons test (α = 0.05). The RelyX Unicem 2 Automix and Panavia F 2.0 specimens showed no statistically significant difference in the mean DC after the use of different LED irradiance levels (P = 0.15 and P = 0.91, respectively) or when photocured with or without the use of a zirconia disc (P = 0.56 and P = 0.86, respectively). The Calibra specimens cured at the lowest irradiance level (855 mW/cm2) presented a significantly lower mean DC (P = 0.001). However, there was no statistically significant difference in the mean DC values when Calibra was photocured directly or through a zirconia disc (P = 0.33). The interpositioning of a high-translucency zirconia material did not reduce the DC of the tested resin luting agents compared to directly irradiated resin luting agents. The influence of different LED irradiance levels on the DC of dual-cured resin luting agents was material dependent.

Adhesion to a Lithium Disilicate Glass Ceramic Etched with Hydrofluoric Acid at Distinct Concentrations.

This study evaluated the effect of different hydrofluoric acid (HF) concentrations on the bond strength between a lithium disilicate-based glass ceramic and a resin cement. Eighty ceramic-blocks (12×7×2 mm) of IPS e.Max CAD (Ivoclar Vivadent) were produced and randomly assigned to 8 groups, considering 2 study factors: HF concentration in 4 levels, i.e., 1% (HF1), 3% (HF3), 5% (HF5), and 10% (HF10), and storage in 2 levels, i.e., baseline (tests were performed 24 h after cementation), and aged (storage for 150 days + 12,000 thermal-cycles at 5°C and 55°C). Acid etching (20 s) was performed, followed by washing, drying, and silanization. Four resin cement cylinders (ϕ= 0.96 mm) were built-up from starch matrices on each ceramic sample (n= 40). Additional ceramic samples were etched and analyzed for contact angle, micro-morphology, and roughness. In baseline condition (without aging), the HF3, HF5, and HF10 groups showed similar bond strength values (13.9 - 15.9 MPa), and HF1 (11.2 MPa) presented lower values than HF5, being that statistically different (p= 0.012). After aging, all the mean bond strengths statistically decreased, being that HF3, HF5, and HF10 (7.8 - 11 MPa) were similar and higher than HF1 (1.8 MPa) (p= 0.0001). For contact angle, HF3, HF5, and HF10 presented similar values (7.8 - 10.4°), lower than HF1 and CTRL groups. HF5 and HF10 presented rougher surfaces than other conditions. For better bond strength results, the tested ceramic may be etched by HF acid in concentrations of 3%, 5%, and 10%.

Effect of etching with distinct hydrofluoric acid concentrations on the flexural strength of a lithium disilicate-based glass ceramic.

This study examined the effects of distinct hydrofluoric acid concentrations on the mechanical behavior of a lithium disilicate-based glass ceramic. Bar-shaped specimens were produced from ceramic blocks (e.max CAD, Ivoclar Vivadent). The specimens were polished, chamfered, and sonically cleaned in distilled water. The specimens were randomly divided into five groups (n = 23). The HF1, HF3, HF5, and HF10 specimens were etched for 20 s with acid concentrations of 1%, 3%, 5%, and 10%, respectively, while the SC (control) sample was untreated. The etched surfaces were evaluated using a scanning electron microscope and an atomic force microscope. Finally, the roughness was measured, and 3-point bending flexural tests were performed. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey's test (α = 0.05). The Weibull modulus and characteristic strength were also determined. No statistical difference in the roughness and flexural strength was determined among the groups. The structural reliabilities (Weilbull moduli) were similar for the tested groups; however, the characteristic strength of the HF1 specimen was greater than that of the HF10 specimen. Compared with the untreated ceramic, the surface roughness and flexural strength of the ceramic were unaffected upon etching, regardless of the acid concentration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 885-891, 2017.

Adhesion to a lithium disilicate glass ceramic etched with hydrofluoric acid at distinct concentrations

Abstract This study evaluated the effect of different hydrofluoric acid (HF) concentrations on the bond strength between a lithium disilicate-based glass ceramic and a resin cement. Eighty ceramic-blocks (12×7×2 mm) of IPS e.Max CAD (Ivoclar Vivadent) were produced and randomly assigned to 8 groups, considering 2 study factors: HF concentration in 4 levels, i.e., 1% (HF1), 3% (HF3), 5% (HF5), and 10% (HF10), and storage in 2 levels, i.e., baseline (tests were performed 24 h after cementation), and aged (storage for 150 days + 12,000 thermal-cycles at 5°C and 55°C). Acid etching (20 s) was performed, followed by washing, drying, and silanization. Four resin cement cylinders (ϕ= 0.96 mm) were built-up from starch matrices on each ceramic sample (n= 40). Additional ceramic samples were etched and analyzed for contact angle, micro-morphology, and roughness. In baseline condition (without aging), the HF3, HF5, and HF10 groups showed similar bond strength values (13.9 - 15.9 MPa), and HF1 (11.2 MPa) presented lower values than HF5, being that statistically different (p= 0.012). After aging, all the mean bond strengths statistically decreased, being that HF3, HF5, and HF10 (7.8 - 11 MPa) were similar and higher than HF1 (1.8 MPa) (p= 0.0001). For contact angle, HF3, HF5, and HF10 presented similar values (7.8 - 10.4°), lower than HF1 and CTRL groups. HF5 and HF10 presented rougher surfaces than other conditions. For better bond strength results, the tested ceramic may be etched by HF acid in concentrations of 3%, 5%, and 10%.

Resumo Este estudo avaliou o efeito de diferentes concentrações de ácido fluorídrico (HF) na resistência de união entre uma cerâmica vítrea à base de dissilicato de lítio e um cimento resinoso. Oitenta blocos cerâmicos (12×7×2 mm) de IPS e.Max CAD (Ivoclar Vivadent) foram produzidos e distribuídos aleatoriamente em 8 grupos, considerando 2 fatores de estudo: concentração de HF em 4 níveis, isto é, 1% (HF1), 3% (HF3), 5% (HF5), e 10% (HF10), e armazenamento em 2 níveis, isto é, condição inicial (testes foram realizados 24 h após a cimentação), e envelhecidos (150 dias de armazenamento + 12.000 ciclos térmicos a 5°C e 55°C). Condicionamento ácido (20 s) foi realizado, seguido por lavagem, secagem e silanização. Quatro cilindros de cimento resinoso (ϕ= 0.96 mm) foram construídos a partir de matrizes de amido em cada amostra cerâmica (n= 40). Amostras cerâmicas adicionais foram condicionadas e analisadas quanto ao ângulo de contato, micro-morfologia e rugosidade. Na condição inicial (sem envelhecimento), os grupos HF3, HF5, e HF10 mostraram valores de resistência de união similares (13.9 - 15.9 MPa), e HF1 apresentou valores menores que HF5, sendo estatisticamente diferente (p= 0.012). Após o envelhecimento, todas as médias de resistência de união diminuíram estatisticamente, sendo que HF3, HF5 e HF10 foram similares e maiores que HF1 (p= 0.0001). Para o ângulo de contato, HF3, HF5 e HF10 apresentaram valores similares (7.8 - 10.4°), menores que os grupos HF1 e CTRL. HF5 e HF10 apresentaram superfícies mais rugosas que as outras condições. Para melhores resultados de resistência de união, a cerâmica testada pode ser condicionada com ácido fluorídrico nas concentrações de 3%, 5% e 10%.

Tratamento estético de lesões não cariosas: série de casos / Aesthetic treatment of non-carious lesions: a case series

As lesões não cariosas têm sido frequentemente motivo de queixa de pacientes odontológicos, sobretudo quando elas têm implicações estéticas. A etiologia desses desgastes é multifatorial, sendo proveniente de processos mecânicos, que determinam desgaste por atrição, abrasão e abfração, e químicos, como a erosão. O aumento da incidência de lesões desse tipo direcionou maior atenção ao diagnóstico multidisciplinar e levou ao desenvolvimento de novas opções de terapias restauradoras minimamente invasivas. A presente série de casos de busca apresentar uma opção conservadora e multidisciplinar, desde o diagnóstico ao tratamento e proservação de desgastes dentários de diversas etiologias, com especial atenção para a estética e saúde geral do paciente...

Non-carious lesions have increasingly become a cause of patients complaint, especially when aesthetic implications are involved. The etiology of non-carious tooth wear is multifactorial. Mechanical processes which produce wear by attrition, abrasion and abfraction, and chemicals factors which produce tooth loss by erosion. The increasing incidence of these lesions led to a greater attention to multidisciplinary diagnosis and the development of new options of minimally invasive restorative therapies. This case series aims to presents a conservative and multidisciplinary approach, from diagnosis to treatment and proservation of tooth wear of various etiologies, with special attention to the aesthetics and patient’s general health...