|Support type:||Scholarships in Brazil - Master|
|Effective date (Start):||July 01, 2013|
|Effective date (End):||January 31, 2015|
|Field of knowledge:||Health Sciences - Dentistry|
|Principal Investigator:||Helena de Freitas Oliveira Paranhos|
|Grantee:||Carolina Noronha Ferraz de Arruda|
|Home Institution:||Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil|
The aim of this study is to determine the antimicrobial effect of Sodium Hypochlorite solutions(in in different concentrations) and experimental solution based on castor beans (Ricinus communis)- regarding the antimicrobial property and removal of biofilms, and through laboratory study the adverse effects of these solutions on the thermally activated acrylic resin. For clinical analysis, approximately 50 patients will be recruited and instructed to brush their dentures (Denture brush and liquid neutral soap) three times a day and dip them (20 minutes), once daily, in the solutions: Group I- saline (control) Group II-Sodium Hypochlorite 0.10%, Group III-Sodium Hypochlorite 0.20%; Group IV-Solution experimental castor 8%. According to a randomized sequence, each solution will be used for 14 days, with a washout period of 7 days between solutions, when the patients will be instructed to keep their usual cleaning. Evaluations will be performed before ("Baseline") and after 14 days of use of each of the solutions. For biofilm removal property, the inner surface of each upper prosthesis is shown (1% neutral red) and photographed (Canon EOS Digital Rebel). The photographs will be processed (Adobe Photoshop 5.5) and biofilm measured by software (Image Tool 3.00). The antimicrobial action is evaluated by counting the colony forming units (CFU) of strains of the genus Candida. After photography, each prosthesis is placed in Petri dishes and brushed (brush and brine Tek) for 2 minutes, the suspension transferred to a test tube. After decimal dilutions (100 to 103), 50 uL ml aliquots of each dilution are cultivated in Petri dishes containing agar-Mitis Salivarius agar and Chromagar for detecting Candida sp. After incubation (aerobic) for 48 hours, the number of colony characteristics will be measured using stereomicroscopy, considering colonies with typical morphology. For Laboratory Analysis, will be evaluated the color stability, surface roughness and flexural strenght of a acrylic resin after twenty minutes immersion in denture cleansers, simulating a period of five years of use (1825 days). One hundred sixty specimens(eighty disc-shaped - 16 mm x 4 mm - and eighty - 65 mm x 10 mm x 3.3 mm - will be prepare from heat-polymerized acrylic resin (Lucitone 550). The specimens will be immersed in the same groups of clinical tested solutions (Group I- saline (control) Group II-Sodium Hypochlorite 0.10%, Group III-Sodium Hypochlorite 0.20%; Group IV-Solution experimental castor 8%. After deflasking, finishing and polishing, the specimens are immersed (20 minutes) in the solutions mentioned. Before and after the immersion, the specimens are evaluated for color change through spectrocolorimeter (Color Guide 45/0) and the correlation data in accordance with NBS unit (E * x NBS = 0.92), as the surface roughness (rugosimeter Surftest SJ-201P) and flexural strength (Universal Testing Machine DL 2000, EMIC).