Dual-cured adhesive system improves adhesive properties of dentin cavities restored with a bulk-fill resin composite

Aim: To evaluate the impact of a dual-cured adhesive system on the in situ degree of conversion (DC), bond strength (BS) and failure mode (FM) of adhesive interfaces in dentin cavities restored with a bulk-fill resin composite. Methods: 4-mm-deep dentin cavities with a 3.1 C-factor were created in 68 bovine incisors (n = 17 per group). The lightcured (Scotchbond™ Universal) or the dual-cured (Adper™ Scotchbond™ Multi-purpose Plus) adhesive system was applied to the cavities, which were then restored with a bulkfill resin composite (Filtek™ Bulk Fill). In situ DC analysis was performed by means of micro Raman spectroscopy at the top and bottom interfaces. Push-out BS was measured in a universal testing machine after 24-h or 6-month water storage. FM was determined with a stereomicroscope. Data of in situ DC and BS were analyzed by two-way analysis of variance (ANOVA) and Tukey test (p<0.05), while the FM was analyzed descriptively. Results: The groups that received the dual-cured adhesive system showed statistically higher in situ DC and BS than those that received the light-cured adhesive system. Cohesive failure mode was the most frequent in all conditions. Conclusion: In situ DC and BS were influenced by the curing strategies of the adhesive systems with better performance of the dual-cured material

Avaliação in vitro da razão base/topo de dureza e da resistência de união push-out entre uma resina composta contendo diatomita e uma resina composta bulk-fill / In vitro evaluation of the base/top hardness ratio and push-out bond strength between a diatomite-containing composite resin and a bulk-fill composite resin

A escassez de dados científicos que validem os benefícios da diatomita para as propriedades físicas da resina composta Zirconfill® torna imperioso a realização de novos estudos, principalmente no tocante a utilização dessa resina contendo diatomita em restaurações semidiretas. Objetivo: Avaliar in vitro a polimerização e resistência de união entre uma resina composta contendo diatomita e de uma resina composta bulk-fill após 24 horas e após 06 meses de envelhecimento em água. Materiais e métodos: Foram utilizados 28 incisivos bovinos para produzir cavidades dentinárias cônicas (4,8 mm de diâmetro maior x 2,8 mm de diâmetro menor x 4 mm de espessura) e fator C de magnitude 3,1. Esses preparos cavitários (n=28) foram restaurados com as resinas compostas Filtek™ One Bulk-fill (BF) (3M ESPE) ou Zirconfill ® (ZF) (BM4), através da técnica semidireta, utilizando o sistema adesivo Single Bond Universal (3M ESPE) e o cimento resino dual Relyx™ Ultimate (3M ESPE). A análise da polimerização foi realizada através da razão base/topo (B/T) de dureza Vickers. E a resistência de união RU foi realizada através do teste de extrusão push-out em máquina de ensaio universal. As amostras foram armazenadas em água destilada a 37 ºC por 24 horas ou 06 meses, mas apenas a RU avaliou as amostras após 06 meses de envelhecimento. Os dados da B/T e da RU foram submetidos à análise de variância (ANOVA) a um e a dois critérios, respectivamente, com pós-teste de Tukey (p <0.05). Resultados: Não houve diferença estatisticamente significativa entre as resinas compostas na B/T. Para a RU, a resina composta ZF mostrou valores maiores do que a resina BF em ambos os tempos avaliados. Não houve diferença estatisticamente significativa de nenhuma resina na avaliação ao longo do tempo. Conclusão: A resina composta contendo diatomita mostrou-se promissora quando utilizada em restaurações semidiretas, visto que obteve resultados similar e até superior a resina composta bulk-fill (AU).

The scarcity of data validating scientific diatomite benefits for physical properties of Zirconfill® resin composite makes essential to develop new studies, especially regarding the use of this resin composite containing diatomite in semi-direct restorations. Aim: To evaluate in vitro the cure and bond strength between a resin composite containing diatomite and a bulk-fill resin composite after 24 hours and after 06 months of water storage. Materials and methods: Twenty-eight bovine incisors (n=28) were used to produce conical dentinal cavities (4,8 mm of larger diameter x 2,8 mm of smaller diameter x 4 mm of thickness) and C-factor of magnitude 3.1. These cavities were restored with Filtek™ One Bulk-Fill (BF) (3M ESPE) or Zirconfill® (ZF) (BM4) resin composites, through the semi-direct technique, using Scotchbond™ Universal (3M ESPE) adhesive system and Relyx™ Ultimate (3M ESPE) dual resin cement. The cure analysis was performed through bottom-to-top (B/T) ratio of vickers hardness, while bond strength (RU) was performed through the push-out test in a universal testing machine. The specimens were stored in distilled water at 37 ºC for 24 hours or 06 months, but only RU analyzed the specimens after 06 months aging. B/T and RU data were, respectively, submitted to one-way and two-way analysis of variance (ANOVA) with Tukey's post-test (p <0.05). Results: There was no statistically significant difference between the composite resins in B/T. For RU, the ZF composite resin showed higher values than the BF resin at both evaluated times. However, there was no statistically significant difference in resin composites over time. Conclusion: The resin composite containing diatomite showed promise when used in semi-direct restorations since it obtained similar or even superior results to bulk-fill resin composite (AU).

Effect of Spondias mombin L. extract on the wettability, roughness, color and morphology of bovine enamel

Although Spondias mombin L. extract has an excellent antimicrobial effect against oral microorganisms, it should be clarified how it affects enamel surface properties. Aim: To evaluate the color change, wettability/contact angle, surface roughness and morphology of bovine enamel submitted to the Spondias mombin L. extract. Methods: Thirty bovine teeth were distributed into the following groups: 0.12% chlorhexidine digluconate, 1:32 Spondias mombin L. extract and distilled water. Color change (CC) was evaluated after immerging specimens into the solutions for 14 days. Surface roughness (Ra) was measured using a roughness meter; wettability/contact angles (CA) were determined by the sessile drop method, and scanning electron microscopy images were obtained to characterize the morphology (SMA). The pH of the solutions was evaluated using a pHmeter. The Ra, CA, and CC data were parametric (Kolmogorov-Smirnov; p>0.05). Two-way ANOVA (for Ra and CA) and one-way ANOVA (for CC) with Tukey's posthoc tests at a significance level of 5% were used. SMA was analyzed descriptively. Results: The Spondias mombin L. extract revealed an acidic pH, and when in contact with the bovine teeth, it increased the wettability, but it did not cause statistically significant differences in the Ra. Spondias mombin L. extract caused the highest color change. The SEM images showed differences in the specimens' surface submitted to the extract compared to the other groups. Conclusion: Spondias mombin L. extract provided negative effects on bovine enamel's surface, including a high color change and a more wettable substrate

Degree of conversion, translucency and intrinsic color stability of composites during surface modeling with lubricants

The tackiness presented by resins causes problems in performing the incremental technique, which can be improved by using lubricants in handling. Aim: To evaluate the influence of two adhesive systems as brush lubricants on the degree of conversion, translucency and intrinsic color stability of composite resins. Methods: Samples (n=10) were fabricated according to the composites (Filtek Z350 XT, IPS Empress Direct, and Esthet X HD), shades (bleach shade and A2), and lubricants used (Adper Single Bond 2, Adper Scotchbond Multi-Purpose bonding agent, and no lubricant). Single composite increments were inserted into a Teflon mold. The composite surface was then modeled using a brush dipped in an adhesive system. The control group was fabricated with no additional modeling. The surface degree of conversion (DC) was measured using Fourier transform infrared spectroscopy; translucency and intrinsic color stability were accessed using a spectrophotometer. Data were analyzed using three-way ANOVA and the Tukey test (p<0.05). Results: Scotchbond Multi-Purpose decreased the DC of all composites and shades in comparison with the control group (p<0.05), although it did not decrease color stability (p<0.05). The bleach shade of IPS Empress Direct and Esthet X HD showed higher translucency than the A2 shade when lubricated with the adhesive systems (p<0.05). Conclusion: Therefore, the two tested adhesive systems used as brush lubricants on composites promoted changes to the surface degree of conversion and aesthetic properties

Interaction between photoactivators and adhesive systems used as modeling liquid on the degree of conversion of a composite for bleached teeth / Interação entre fotoativadores e sistemas adesivos usados como líquido modelador no grau de conversão de um compósito para dentes clareados

Objective: This study analyzed the effect of two light emitting diodes (LEDs) on the degree of conversion (DC) of a composite resin for bleached teeth under the influence of adhesive systems used as modeling liquid. Material and Methods: A total of 60 samples of IPS Empress Direct resin (Ivoclar, Vivadent) in BL-L shade were made in a single increment and polymerized for 20 seconds. The treatments were: 1) Type of adhesive used as modeling liquid (Adper Single Bond 2; the bond component of Adper Scotchbond Multi-Purpose; or no adhesive systems used as modeling liquid were used in the control group); and 2) Type of LED (Bluephase, polywave; and Coltolux, monowave). The DC, percentage of monomers converted to polymer during polymerization, was evaluated using Fourier Transform Infrared Spectroscopy (FTIR) with 10 scans and wavenumber related to 1/λ for observation of the peaks at 1608 and 1638 cm-1. Data were statistically analyzed by two-way analysis of variance (ANOVA) with Tukey's test (p < 0.05). Results: There was no statistical difference between LEDs in comparison to the treatments (p > 0.05). However, there was a statistically significant increase in the DC for the adhesive systems tested in comparison to the control group (p < 0.05), with the highest values for Single Bond 2. Conclusion: It is concluded that the use of adhesives as modeling liquid of Empress Direct resin for bleached teeth shade increases the degree of conversion of the composite surface, and that curing with both kinds of LEDs does not interfere in this property (AU)

Objetivo: Esse estudo analisou o efeito de dois diodos emissores de luz (LEDs) no grau de conversão (GC) de uma resina composta para dentes clareados sob a influência de sistemas adesivos usados como líquido modelador. Material e Métodos: Um total de 60 amostras da resina IPS Empress Direct (Ivoclar, Vivadent) na cor BL-L foram feitas em incremento único e polimerizadas por 20 segundos. Os tratamentos foram: 1) Tipo de adesivo usado como líquido modelador (Adper Single Bond 2; o componente "bond" do Adper Scotchbond Multi-Purpose; ou nenhum dos sistemas adesivos usados como líquido modelador foram utilizados no grupo controle); e 2) Tipo de LED (Bluephase, polifásico; e Coltolux, monofásico). O GC, percentual de monômeros convertidos em polímero durante a polimerização, foi avaliado usando Espectroscopia de Infravermelho com Transformada de Fourier (FTIR) com 10 varreduras e número de ondas relacionado de 1/λ para a observação dos picos de 1608 e 1638 cm-1. Os dados foram analisados estatisticamente por análise de variância (ANOVA) a dois fatores com pós-teste de Tukey (p < 0,05). Resultados: Não houve diferença estatística entre os LEDs na comparação para os tratamentos (p > 0,05). Entretanto, houve um aumento estatisticamente significativo no GC para os sistemas adesivos testados em comparação com o grupo controle (p < 0,05), com os maiores valores para o Single Bond 2. Conclusão: Conclui-se que o uso de adesivos como líquido modelador da resina Empress Direct para dentes clareados aumenta o grau de conversão de superfície dos compósitos e que a fotoativação com ambos os tipos de LEDs não interfere nessa propriedade (AU)