Stéfani Becker Rodrigues

Chlorhexidine application in adhesive procedures: a meta-regression analysis.

PURPOSE To evaluate the association between chlorhexidine application and the bond strength of an adhesive system to dentin and to assess the association among eight other variables. MATERIALS AND METHODS Laboratory studies evaluating the use of chlorhexidine on dentin that verified the immediate and longitudinal bond strength were included. The terms were selected according to the Medical Subject Headings (MeSH) for PubMed and adapted for the other databases accordingly. Systematic searches were conducted in 3 electronic databases in December 2010: PubMed, EMBASE, and LILACS. Languages were limited to English, Spanish, and Portuguese. RESULTS All longitudinal bond strength studies were analyzed in accordance with the inclusion/exclusion criteria, totaling 16 articles. A meta-regression analysis was performed with articles containing complete mean bond strength data (n = 14 articles). CONCLUSION Our results showed that the association between the concentration of chlorhexidine and the bond strength is, apparently, not linear. Therefore, future large-scale studies should be developed to investigate the association between the chlorhexidine concentration and hybrid layer preservation.

Acrylic resin disinfection by peracetic acid and microwave energy

Objective: The objective of this study was to evaluate the effectiveness of disinfection methods in microwave and immersion in peracetic acid in heat-cured, self-cured and microwave-cured acrylic resin, contaminated with Candida albicans.Methods: Five specimens were prepared for each type of acrylic resin. All were infected with Candida Albicans, incubated at 37°C for 24 hours. The group which underwent microwave energy was irradiated with a power of 840W for 1 minute and the other group underwent disinfection by soaking of 0.2% peracetic acid for 5 minutes.Results: All samples proved to be contaminated after the incubation period. After the different processes of disinfection, both immersion in 0.2% peracetic acid as microwave irradiation were effective in disinfection of the 3 types of acrylic resins contaminated by Candida Albicans.Conclusion: Concluded that soaking in 0,2% peracetic acid for 5 minutes with microwave irradiation power 840W for 1 minute are effective methods for disinfecting heat-cured acrylic resin, self-cured acrylic resin and microwave-cured acrylic resin, contaminated with Candida Albicans.

Influence of dye and nylon fibers on microwave-cured acrylic resin properties

ABSTRACT ObjectiveThe aim of this study is to analyze if both color and nylon fibers have an influence on microwave-cured acrylic resin properties.MethodsRectangular and disk-shaped specimens were prepared using acrylic resins; medium pink with and without nylon fibers and colorless without nylon fibers. To obtain the rectangular specimens, a stainless steel die was used with the following dimensions: 64 X 10 x 3 mm (± 0.5mm). To obtain disk-shaped specimens, a die 50mm (±0.5mm) in diameter and 0.5mm (±0.05mm) thick was employed. They were randomized to form groups: control (colorless acrylic) and experimental (medium pink, with and without nylon fibers), with each group consisting of ten (10) specimens rectangular in shape and five (5) disk-shaped. They were analyzed in six (6) assays (izod impact strength, n=10; Knoop hardness, n=10; glass transition temperature, n=3; water sorption and solubility, n=5; degree of monomer/polymer conversion, n=1; flexural strength and flexural modulus, n=10). All variables were subjected to the analysis of variance test followed by Tukey’s multiple comparison test, at a 5% level of significance.ResultsThe analysis of the monomer/polymer degree of conversion did not reveal any difference between the three groups of resins (medium pink, with and without nylon fibers and colorless resin); it was approximately 88%. The results did not show significant differences between the groups for each variable (p>0.05). ConclusionThe results showed that color and presence of nylon fibers in acrylic resins did not affect the properties analyzed in this study.Indexing terms: Acrylic resins. Microwave. Nylons.