ABSTRACT
This study evaluated the effects of humidity conditions and evaluation times on the dentin bond strength (DBS) of two self-adhesive resin cements (RC). The RC used were: RelyX Unicem (3M ESPE) and Clearfil SA Cement (Kuraray Med.). One hundred and twenty coronal portions of bovine incisors (n = 10) were used. Buccal surfaces were abraded in order to expose a flat dentinal surface (180-grit SiC) and to standardize the smear layer formation (600-grit SiC). The humidity conditions tested were: dry (air-dried for 10 s), slightly moist (water application with disposable applicator on dried dentin and water excess removed with absorbent paper), and moist (same application without water removal). The RC were used according to the manufacturers' recommendations and were applied to prepolymerized resin discs (2 mm thick; Sinfony, 3M ESPE), which were subsequently bonded to the dentin surfaces. After 24 h, half of the teeth were prepared for the microtensile bond strength test, while the other half were stored in water for 6 months and tested in tension (0.5 mm/min) until failure. A 3-way analysis of variance and the Tukey test were performed (preset alpha of 0.05). No RC showed any reduction of DBS after 6 months, and no significant difference was observed between them. The moist dentin increased the bond strength of Clearfil SA Cement for both periods of time. Humidity conditions can change the DBS; however, the study's results were product-dependent.
Subject(s)
Animals , Cattle , Dental Bonding/methods , Dentin-Bonding Agents/chemistry , Dentin/chemistry , Resin Cements/chemistry , Analysis of Variance , Dentin/drug effects , Humidity , Materials Testing , Surface Properties , Tensile Strength , Time Factors , Water/chemistryABSTRACT
Aim: To evaluate the influence of the viscosity and curing mode on the bond strength of two resincements to dentin. Methods: Eight experimental groups were formed (n = 7) according to thedual-cure resin cements (Nexus 2 - Kerr Corp. and Variolink II - Ivoclar Vivadent), curing modes(dual-cure or self-cure) and viscosities (low and high). Resin cements were applied to pre-curedcomposite resin discs (2 mm thick, Sinfony -3M ESPE), which were fixed to bonded dentinsurfaces. The restored teeth were either light-activated (XL3000 - 3M ESPE) or allowed to selfcuring only. After 24 h, the teeth were both mesiodistally and buccolingually sectioned to obtainbonded beam specimens (0.8 mm2 cross-sectional area). Each specimen was tested in microtensilestrength at a crosshead speed of 0.5 mm/min until failure. Results: Data (in MPa) were analyzedstatistically by three-way ANOVA and Tukeys post-hoc test (pre-set á = 0.05). No significantdifference was observed between resin cements (p=0.26) and viscosities (p=0.13), however, thecuring mode affected the BS within the viscosities (p=0.01). Statistically significant difference wasobserved for low viscosity: Nexus 2: 23.8(10.6) (dual-cure) and 16.0(5.1) (self-cure); VariolinkII: 28.7(8.7) (dual-cure) and 11.9(3.0) (self-cure). Conclusions: Light activation yielded higherbond strength for the low-viscosity versions of the resin cements.
Subject(s)
Dentin , Resin CementsABSTRACT
O objetivo deste estudo foi avaliar o efeito da aplicação de primers para estruturas à base de ligas metálicas na resistência de união (RU) de um cimento convencional e de um cimento autoadesivo à zircônia, utilizando o teste de microcisalhamento. Foram preparadas 60 placas de óxido de zircônia (Cercon), com dimensões de 13 x 5 x 1 mm (comprimento x largura x espessura). Essas placas foram jateadas com óxido de alumínio e divididas em seis grupos experimentais, segundo o tratamento utilizado (n = 10). Os primers e cimentos foram aplicados de acordo com as recomendações dos fabricantes e grupos experimentais. Após o tratamento da zircônia, cilindros de cimento resinoso foram construídos na superfície das placas, utilizando matrizes (Tygon) com 0,7 x 1 mm (diâmetro x altura). As amostras foram armazenadas em água destilada por 24 h à 37ºC e submetidas ao ensaio de microcisalhamento (0,5 mm/min, Instron 4411). Os valores obtidos foram analisados pela ANOVA (2 fatores) e teste Tukey (α = 0.05). Somente a utilização do Metal Primer II aumentou a RU dos dois cimentos resinosos à zircônia. O cimento autoadesivo RelyX U-100 obteve as maiores médias de RU quando comparado ao cimento convencional Bistite II DC, para todos os tratamentos de superfície utilizados. Para se obter maior RU à zircônia Cercon deve ser utilizado o Metal Primer II e o cimento autoadesivo RelyX U-100.
The aim of this study was to evaluate the effect of alloy primers on the bond strength (BS) of conventional resin cement and self-adhesive cement to zirconia using the microshear bond strength test. Sixty ceramic plates, with dimensions of 13 x 5 x 1 mm (length x width x thickness), were prepared . The ceramic plates were air-abraded with aluminum oxide and divided into six experimental groups, according to the treatment used (n = 10). The primers and resin cements were applied according to manufacturers' recommendations and experimental groups. After treatment of the zirconia, resin cement cylinders were constructed on their surfaces by using matrix (Tygon) with 0.7 x 1 mm (diameter x height). The samples were stored in distilled water for 24 hours at 37°C and tested in a universal testing machine (0.5 mm/min, Instron 4411). The data were analyzed by ANOVA (two factors) and Tukey test (α = 0.05). Only the use of Metal Primer II increased the bond strength of all resin cements to zirconia. The self-adhesive RelyX U-100 cement promoted higher bond strength values than Bistite II DC, for all surface treatments. To obtain the highest bond strength to zirconia, it must be used the Metal Primer II and the self-adhesive RelyX U-100 resin cement.
ABSTRACT
O aumento da demanda por restaurações estéticas é uma realidade na clínica odontológica, sendo que essa tendência é observada não só no tratamento de dentes anteriores, mas também na região posterior. Alternativas restauradoras, como o uso de resinas compostas diretas, inlays, onlays e coroas em resina ou cerâmica, visam o equilíbrio funcional e estético dos dentes posteriores. Entretanto, a escolha da técnica empregada está principalmente associada à técnica empregada, está principalmente associada à condição do remanescente dentário. Assim, através do relato de um caso clínico, esse artigo busca conceituar importantes aspectos quanto ao uso de resinas compostas e restaurações indiretas do tipo onlay cerâmicos, enfatizando a importância na indicação desses dois tratamentos restauradores estéticos para dentes posteriores.
Subject(s)
Humans , Female , Adult , Ceramics , Composite Resins , Inlays/methods , Tooth Crown , Dental Restoration, Permanent , Esthetics, Dental , RadiographyABSTRACT
O estudo avaliou a resistência de união (RU) ao esmalte e à dentina de dois novos sistemas adesivos: Tetric N-Bond (TN), que preconiza o condicionamento ácido separado e o autocondicionante Bond Force. A superfície vestibular de 24 incisivos bovinos foi desgastada para exposição do esmalte e dentina. As amostras foram alatoriamente distribuídas em quatro grupos (n=6). Três cilindros de resina composta foram obtidos por dente. Após, as amostras foram submetidas ao ensaio de microcisalhamento e as médias abalisadas estatisticamente (Anova, p<0.05). O adesivo TN apresentou valores superiores e a RU ao esmalte foi maior para os dois adesivos.