Criopreservação do plasma rico em plaquetas de equinos / Equine platelet-rich plasma cryopreservation

Avaliou-se o congelamento do plasma rico em plaquetas (PRP) de equinos, a -196ºC em nitrogênio líquido, utilizando-se como crioprotetor o DMSO em duas concentrações (3% e 6%), e, como ponto final, a avaliação da morfologia e da agregometria plaquetária. Foram utilizadas 12 amostras de PRP em duas repetições. Previamente ao congelamento, as amostras foram submetidas a um resfriamento lento (-0,07ºC/minuto) até a temperatura final de 4-5ºC. A criopreservação do PRP equino, incluindo um resfriamento lento a 4-5ºC, previamente ao congelamento a -197ºC em nitrogênio líquido, foi similar para as concentrações do crioprotetor DMSO a 3% ou 6%, quando avaliado o percentual de ativação e de agregação plaquetária.

Equine platelet-rich plasma (PRP) frozen at -196°C in liquid nitrogen using DMSO as a cryoprotectant in two different concentrations (3% and 6%) was evaluated, using platelet morphology and aggregometry as the final parameters. Twelve PRP samples were used in two repetitions. The samples were submitted to slow cooling prior to frozen (-0.07°C/minute) until they reached the temperature of 4-5°C. Platelet cryopreserved in 3% or 6% DMSO, presented similar efficacy when the percentage of activation and platelet aggregation was evaluated.

Pullout bond strength of fiber posts luted to different depths and submitted to artificial aging.

INTRODUCTION: The extension of fiber post cementation often does not seem to influence the fracture resistance of restorations. This study evaluated the effects of cementation depths on the retention of fiber posts submitted to artificial aging. METHODS: One hundred and sixty bovine incisors were selected to assess post retention. Following endodontic treatment, the canals were flared with diamonds burs. Postholes were prepared in lengths of 5 or 10 mm, after which fiber posts were relined with composite resin and luted with RelyX ARC or RelyX Unicem. The samples were then submitted to thermal and/or mechanical cycling before testing their pullout bond strengths. Absence of cycling was used as a control. The results of each cement were submitted to two-way and post hoc Tukey tests (α=0.05). RESULTS: Independent of the aging protocol, a depth of 10 mm showed higher pullout bond strength than did 5 mm, except for RelyX Unicem without cycling. For RelyX ARC, thermomechanical cycling resulted in lower values than in the absence of cycling. Mechanical cycling alone promoted the highest bond strength when the posts were luted with RelyX Unicem. CONCLUSION: The effect of artificial aging on the pullout bond strength is dependent on the type of material and the depth.