RESUMO
The purpose of this study has been to investigate the effects of certain substances frequently used in alimentation on the color stability of the composite resin restorative materials. The research hypothesis was that color stability of the composite resin is affected by the type of composite material used and by the polishing procedure. 14 samples of 5X15X2mm have been prepared from seven universal light curing restorative composite resins. The materials have manipulated and cured using LA 500 Blue Light lamp. A first color determination was done before the introduction of the samples in the dyeing agent with the help of an Easy Shade device. The samples have been splited into two lots each with seven samples. The samples from the first lot have been sectioned into three equal segments. The samples from the second lot have also been sectioned into three equal segments, and in addition to the previous group, their exterior surfaces were processed with a diamond burr. For each type of composite we have introduced a sample in one of the three chosen dyes: red alimentary colorant, coffee and red wine. The color of the samples has been determined again using the Vita Easy Shade device. From clinical point of view the results of this study shows that there are three important factors that matter when we talk about durable aesthetic results: the type of composite resin used for the restoration, the finishing and polishing procedures and the pacients' alimentation habits. The composite resins with a good representation of the anorganic structure are easier to be polished, therefore they have only slight color modifications. Using plastic matrixes for shaping the exterior surface of the restoration is the best solution for obtaining a very smooth surface. The most significant color modifications have been done by the red wine. Coffee and to a smaller extent the red alimentary colorant have modified the color of the restoration material in a smaller degree.
RESUMO
Anticoagulation therapy with acenocoumarin or with anticoagulants plus aspirin was given to 65 and 57 patients, respectively, with cardiac valve replacement. The follow-up was 1,462 months (22.5 months per patient) for the first group and 1,411 months (24.7 months per patient) for the second group. The frequency of embolic accidents was significantly lower in the group taking aspirin: Thirteen thromboembolic accidents were detected in patients receiving the anticoagulant and 3 in the group receiving the anticoagulant plus aspirin. These figures represent a 20.3 per cent incidence (one each 9.3 years of treatment) for the anticoagulant group and a 5.2 per cent incidence (one accident each 39.1 years of treatment) for the other group. The statistical significance between groups is p less than 0.005. There was no difference in the hemorrhagic risk between the two groups. We conclude that the use of an anticoagulant plus aspirin is a good and safe therapy for the prevention of thromboembolism in these patients.
