Surface degradation of composite resins under staining and brushing challenges.

BACKGROUND/PURPOSE: The primeval evaluation of the properties of composite resins with different compositions that impact clinical behavior is very important in guiding use in clinical settings. The aim of this study was to evaluate color stability (ΔE) and Knoop microhardness (KHN) of composite resins containing different compositions. MATERIALS AND METHODS: Forty-five disks were made composite resins: Filtek Z350 XT/3MESPE and Beautifill II/SHOFU and divided into 3 subgroups: Control - immersed in artificial saliva; OB - brushing with Oral B 3D White; CT - brushing with Colgate Total 12. The OB and CT groups had the disks brushed daily with 120 cycles after immersion in coffee solution (10 min) for a period of 30 days. ΔE and KHN was obtained at baseline and after the treatments. Data were analyzed ANOVA and Tukey tests (p < 0.05). RESULTS: ANOVA revealed significant differences for ΔE and KHN. ΔE: the highest mean was observed in Beautifil II composite resin group, which differed significantly from Z350 group. For the Beautifil II, the treatments were significantly different from each other. For the Z350, the control group showed significant differences in relation to OB e CT groups. KHN: the highest mean was observed in Z350 group, which differed significantly from Beautifil II group. For Z350, the control group showed significant differences in relation to OB e CT groups. For Beautifil II, the treatments did not differ significantly among themselves. CONCLUSION: The composite resin containing fluoride in the composition showed higher color alteration (ΔE) and lower Knoop microhardness (KHN), thus demonstrating that composition is an important factor in the clinical performance of esthetic restorative materials.

Avaliação do efeito do plasma não térmico na resistência adesiva à dentina superficial e profunda / Effect of non-thermal plasma on bond strength to superficial and deep dentin

O tratamento com plasma não térmico pode modificar a superfície da dentina e melhorar a ligação entre os dentes e resinas compostas. O objetivo deste estudo foi avaliar a influência do tratamento do plasma não térmico (PNT) na resistência adesiva de um sistema adesivo auto condicionante aplicado em diferentes espessuras de dentina humana, bem como observar mudanças na micromorfologia das interfaces dentina/resina em MEV. Molares humanos foram divididos em dois grupos (n = 30) de acordo com a espessura da camada de dentina: superficial (S) (2 mm de espessura) e profunda (P) (1 mm de espessura). Cada grupo foi dividido em três subgrupos (n = 10) de acordo com o tratamento de superfície da dentina: grupo SPA (2 mm dentina + plasma + adesivo); Grupo SAP (2 mm dentina + adesivo + plasma); Grupo SA (2mm de dentina + adesivo); PPA (1 mm dentina + plasma + adesivo); Grupo PAP (1 mm dentina + adesivo + plasma) e grupo PA (1 mm dentina + adesivo). Foi confeccionada uma restauração em resina composta e as amostras armazenadas (48 h). Palitos de dentina/resina com área adesiva de aproximadamente 1 mm² foram obtidos e submetidos ao teste de microtração. O padrão de fraturas foi analisado por microscopia óptica. Os dados de resistência foram analisados pelos testes estatísticos ANOVA dois fatores e Tukey (5%). As análises das interfaces adesivas em MEV foram realizadas em amostras selecionadas. Os resultados mostraram uma diferença significativa na resistência adesiva entre a dentina superficial e profunda; independentemente do tratamento de superfície, a dentina superficial apresentou maiores valores de resistência adesiva. Entre os grupos tratados com e sem plasma, a resistência adesiva foi maior quando o plasma foi aplicado na superfície da dentina; no entanto a aplicação de plasma antes ou depois do o adesivo não foi estatisticamente diferente. O PNT aumentou a resistência adesiva da dentina humana S e P

Treatment with non-thermal plasma can modify dentin surface and improve bond between teeth and composite resin. The objective of this study was to evaluate the influence of non-thermal plasma (NTP) treatment on dentin bond strength of a self-etching adhesive system to different thicknesses of human dentin as well as to observe SEM micromorphology changes of the resin/dentin interfaces. Human molars were divided into two groups (n = 30) according to dentin layer thickness: superficial (S) (2 mm thick) and deep (D) (1 mm thick). Each group was divided into three subgroups (n = 10) according to dentin surface treatment: SPA group (2 mm dentin + plasma + adhesive); SAP group (2 mm dentin + adhesive + plasma); Group SA (2 mm dentin + adhesive); PPA (1 mm dentin + plasma + adhesive); PAP group (1 mm dentin + adhesive + plasma) and PA group (1 mm dentin + adhesive). A composite resin restoration was built up and specimens stored (48 h). Teeth sticks with adhesive area of approximately 1 mm² were obtained and submitted to microtensile test. The pattern of fractures was analyzed with optical microscopy. Bond strength data was analyzed by two-way ANOVA and Tukey (5%) statistical tests. Resin/dentin interfaces SEM analysis was conducted on selected specimens. The results showed a significant difference in bond strength between superficial and deep dentin; regardless surface treatment superficial dentin showed higher bond strength. Among the groups treated with and without plasma, bond strength was higher when plasma was applied on dentin surface; however plasma application before or after the adhesive was not statistically different. NTP increased the bond strength of S and D human dentin

Influence of adhesive system in bond strength of fiber glass posts to radicular dentin using dual cure resin cement / Influência do sistema adesivo na resistência de união de pinos de fibra à dentina radicular utilizando cimento resinoso dual

The purpose of this study was to evaluate the bond strength between root dentin and glass fiber posts cemented with dual cure resin cement associated with the total-etch and self-etch adhesive systems. Twenty-four single-rooted human teeth were selected, and the crowns were removed at the cement enamel junction. The roots received biomechanical preparation and obturation followed by the intraradicular preparation compatible with a drill diameter of the glass fiber posts. The roots were divided into two groups, according to cementation protocol (n-12): Group 1 - etched with 37% phosphoric acid for 30 seconds, total-etch adhesive system Single Bond (3M ESPE) and Enforce resinous cement (Dentsply); Group 2 – self-etch adhesive system One Up Bond F (Tokuyama) and Enforce resin cement (Dentsply). After the posts cementation, the roots were kept at 37º C for one week, and submitted to pull out test on the universal testing machine Emic to a traction speed of 1 mm/ min. Data in MPa were submitted to the statistical t-test (5%). The t-test showed significant differences between the two groups (p = 0.003 ). The average values in MPa (±standard-deviation) were: Group 1: 5.28(± 3.25), Group 2: 10.05 (± 3.78). Enforce associated with the self-etch adhesive system One Up Bond F showed significantly higher bond strength values than Group 1 - Enforce associated with the total-etch adhesive system Single Bond.

O objetivo deste estudo foi avaliar in vitro a resistência de união à dentina radicular de pinos estéticos pré-fabricados cimentados com cimento resinoso dual associado aos sistemas adesivos convencionais e autocondicionantes. Foram utilizados 24 dentes unirradiculares, nos quais as raízes foram removidas na junção esmalte-cemento. Realizou-se a instrumentação e a obturação dos canais radiculares seguido do preparo intrarradicular com uma broca compatível com o diâmetro do retentor intrarradicular de fibra de vidro. Os pinos estéticos pré-fabricados foram divididos em 2 grupos, de acordo com o protocolo de cimentação (n - 12): Grupo 1 - condicionamento com ácido fosfórico 37%, aplicação do sistema adesivo convencional Single Bond (3M ESPE) e cimento resinoso Enforce; (Dentsply) Grupo 2 – aplicação do sistema adesivo autocondicionante One Up Bond F(Tokuyama) e cimento resinoso Enforce (Dentsply). Após a cimentação os espécimes foram armazenados a 37º C por 7 dias e submetidos ao ensaio de pull-out na máquina de Ensaio Universal EMIC a uma velocidade de 1 mm/min. Os valores de MPa foram analisados de acordo com teste estatístico de t (5%). O teste t mostrou que houve diferença significante entre os dois grupos (p = 0,003). Os valores de média MPa (±desvio-padrão) são: Grupo 1: 5,28(± 3,25), Grupo 2: 10,05(± 3,78). Enforce associado ao sistema adesivo autocondicionanate One Up Bond F apresentou valores de resistência de união à dentina intrarradicular superiores quando comparado ao Grupo 1 - Enforce associado ao sistema adesivo convencional Single Bond.