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Evaluation of the effect of the sodium hypochlorite and castor bean (Ricinus communis) solutions on denture biofilm removal and adverse effects of the thermically activated acrylic resin

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Author(s):
Carolina Noronha Ferraz de Arruda
Total Authors: 1
Document type: Master's Dissertation
Press: Ribeirão Preto.
Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC)
Defense date:
Examining board members:
Helena de Freitas Oliveira Paranhos; Nara Hellen Campanha Bombarda; Valéria Oliveira Pagnano de Souza
Advisor: Helena de Freitas Oliveira Paranhos
Abstract

This study evaluated denture cleansers efficacy in biofilm removal and antimicrobial action by a randomized crossover trial (\"in vivo\") and the adverse effects of heat-polymerized acrylic resin (\"in vitro\"). The employed solutions were: Group I- Saline (control); Group II- 0.10% Sodium Hypochlorite; Group III- 0.20% Sodium Hypochlorite; Group IV- 8% Castor oil solution (Ricinus comunnis). Ninety-seven complete denture wearers - fifty with Denture Stomatitis and forty-seven with oral healthy - were instructed to brush their dentures (specific brush and liquid soap) three times a day and to soak them (twenty minutes), once a day, for fourteen days. The dentures were soaked in solutions according a randomized sequence with a washout period (7 days), which patients were instructed to use their habitual hygiene. The data were collected at Baseline and after each solution usage. To evaluate the biofilm removal property, the internal surfaces of maxillary dentures were disclosed (1% neutral red) and photographed (Canon EOS Digital Rebel), the biofilm areas (total and stained) were quantified (Image Tool 3.0) and its percentage was calculated using the relation between biofilm area multiplied by 100, and total surface area of the denture\'s internal base. Antimicrobial action was evaluated by counting CFU/mL of characteristic Candida spp. colonies by a stereoscopic magnifier. To collected biofilm, the maxillary dentures internal surfaces were brushed (Tek brush and saline solution) for two minutes. The diluted resultant solutions (100 to 10-3) were cultured (50 &mu;L aliquots) inside Petri plaques containing Chromagar agar (Difco Laboratories Inc., Detroit, Michigan, EUA) for Candida spp.. For \"in vitro\" analyses, eighty disc-shaped (16 mm x 4 mm) and eighty rectangular specimens (65 mm x 10 mm x 3.3 mm) were prepared from heat-polymerized acrylic resin (Lucitone 550) and immersed into solutions for 20 minutes. Color data (&Delta;E) were determined by a colorimeter and also quantified according the National Bureau of Standards. A rugosimeter was used to measure roughness (&mu;m) and the flexural strength (MPa) was measured using a universal testing machine. For biofilm removal and antimicrobial action, data were analyzed by Wilcoxon test, corrected by Bonferroni method (&alpha;=0.05) and Mann-Whitney (&alpha;=0.05) was used to compare patients groups. For \"in vitro\" data were used Kruskal-Wallis, followed by Dunn test (&alpha;=0.05). The results for biofilm removal showed for both patients groups, intermediated values for group IV and groups II and III were the most effectives. Comparing patients groups, just baseline showed significant difference (p=0.025) and the lower values were for patients with oral healthy. Groups II and III showed antimicrobial action for Candida spp. and group IV was effective for oral healthy group. Comparing groups, baseline (p=0.002), group I (p<0.001) and group IV (p<0.001), showed significant difference and patients with oral healthy showed the lower values. The \"in vitro\" data showed significant differences to color alteration (<0.001). Group IV showed higher values, however, color changes caused by solutions were classified as \"slight\" by NBS. The statistical analysis showed no significant difference to surface roughness (p=0.760) and flexural strength (p=0.547) after the simulated period of immersion. It was concluded that 0.10% and 0.20% sodium hypochlorite solutions were effective not only to biofilm removal and antimicrobial action, but also did not cause adverse effects of acrylic resin, and could be used to control denture biofilm (AU)

FAPESP's process: 13/04800-1 - Evaluation of the effect of the sodium hypochlorite and castor bean (Ricinus communis) solutions on denture biofilm removal and adverse effects of the thermically activated acrylic resin
Grantee:Carolina Noronha Ferraz de Arruda
Support Opportunities: Scholarships in Brazil - Master