Different methods of veneering Y-TZP restorations would not influence the clinical performance of the core/veneer interfaces.

In spite of high mechanical strength, zirconia-based ceramics (ZrO 2 ) has poor bond strength after conventional bond cementation procedures, requiring different surface treatment methods (STMs). This review gathered information about the STM for adhesive cementation (AC) to ZrO 2 in the PubMed database, considering in vitro studies pertaining to AC for acid-resistant ceramics (ZrO 2 ) limited to peer-reviewed papers published in English between 1965 and 2013 in dental journals. Different STMs have been proposed for ZrO 2 : air-abrasion (laboratory or chairside) with silica-(Si-) coated aluminum particles, the use of materials containing phosphate monomers, primer or silane application, laser irradiation, Si vapor phase deposition, and selective infiltration etching. In conclusion, STMs improve bond strength of resin luting cement to ZrO 2 mainly when tested in short time. STMs must be correlated to the type of ZrO 2 and the resin cement.

BackgroundTo evaluate the influence of thermal and mechanical fatigue on the shear bond strength of different all-ceramic cores and veneering porcelain interfaces.Material and MethodsAll-ceramic systems tested were lithium disilicate and zirconia veneered by layering technique. Sixty specimens (n=20) were subjected to shear bond strength. Ten of them were thermal and mechanical cycled. Fracture analysis was performed with stereomicroscopy and scanning electron microscopy. Energy dispersive X-ray spectroscopy analysis was performed across core/veneer interfaces.ResultsThermal and mechanical cycling did not influence on bond strength. However, there was significant difference among systems (<0.01). CoCr group presented the highest values, followed by lithium disilicate, and zirconia. Failure modes were predominantly adhesive for CoCr, cohesive in core for lithium disilicate, and cohesive in veneer for zirconia. Energy dispersive X-ray showed interaction zone for CoCr and lithium disilicate groups and was inconclusive for zirconia. Fatigue had no influence on bond strength of groups tested.ConclusionsThe results suggest that there is a chemical bond between core and veneer materials for CoCr and lithium disilicate groups. Key words:Ceramics, electron microscopy, fatigue, mechanical stress, shear bond strength.

Objetivo: Esta pesquisa avaliou a estabilidade dimensional de modelos obtidos de moldes de alginato utilizando a técnica de união dos análogos. Materiais e Métodos: foi utilizado um modelo mestre representando uma mandíbula com 4 implantes osseointegrados instalados, sobre o qual foi realizado a moldagem com moldeira aberta dos transferentes unidos por fio metálico rígido e resina acrílica autopolimerizável, utilizando o alginato. Foram feitas 40 moldagens ao todo, sendo 20 para cada grupo. Após as moldagens, os moldes foram vazados utilizando gesso pedra de alta resistência, sendo que em um grupo foi realizada a união de análogos previamente. Após o término da reação de presa do gesso, os modelos foram levados para análise na lupa estereoscópica, onde foram realizadas 3 medições da distância dos análogos entre si, obtendo-se uma média para cada modelo. Resultados:As médias obtidas foram comparadas com a média da distância entre os análogos e enviadas para análise estatística para a obtenção dos resultados, utilizando o teste Tukey HSD. Os resultados mostraram que as medidas de ambos os grupos tiveram diferenças estatísticas em relação ao modelo mestre, sendo que com a união houve alteração nas medidas A e C e sem a união houve alteração nas medidas A, C e D. Conclusão: Concluiu-se que os modelos com maior fidelidade dimensional são os do grupo com a união de análogos.Descritores: Técnica de Moldagem Odontológica; Implantes Dentários; Prótese Dentária.