Full text
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| Author(s): |
Ana Carolina Pimentel Corrêa
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba |
| Defense date: | 2013-02-21 |
| Examining board members: |
Caio Cezar Randi Ferraz;
Luciano Tavares Angelo Cintra;
José Flávio Affonso de Almeida
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| Advisor: | Caio Cezar Randi Ferraz |
| Abstract | |
The bond strength to dentin is compromised when it is treated with sodium hypochlorite. Several antioxidant solutions have been proposed in order to reestablish the adhesion values. Although several studies have evaluated the efficiency of sodium ascorbate, other substances should be assessed. The purpose of this study was to evaluate the antioxidant efficiency of sodium thiosulfate (Na2S2O3), at different times and concentrations, in reestablishing the adhesive bond strength to sodium hypochlorite-treated dentin. Crowns of bovine incisors were cut to expose the pulp chamber. The dentin surfaces were treated as follows: group 1: 0.9% sodium chloride for 30 min; group 2: treated with 5.25% sodium hypochlorite (NaOCl) for 30 min, 17% EDTA for 3 min and additional 5.25% NaOCl for 1 min; groups 3, 4, 5, 6, 7 and 8: followed the same treatment performed in group 2, adding the final applications of 0.5% sodium thiosulfate solution for 1 min (group 3), 5 min (group 4) and 10 min (group 5) or applications of 5% sodium thiosulfate solution for 1 (group 6), 5 (group 7) and 10 min (group 8); group 9: immersion in 0.9% sodium chloride for 10 min after the same treatment performed in group 2. After that, Scotchbond Multipurpose adhesive system was applied to pulp chamber dentin, followed by Filtek Z250 composite. After storage in water for 24h at 37oC, twenty-five rectangular sticks were obtained from the specimens of each group and subjected to the microtensile bond test. The data converted to MPa were analyzed by one-way ANOVA and Fisher's test (p<0.05). The groups 2 and 9 had significantly lower bond strength than the control (group 1). There was no statistically difference between application of 0.5% or 5% sodium thiosulfate solution for 5 or 10 min to increase the compromised bonding to NaOCl-treated dentin (p>0.05). There was no statistically significant difference between groups 1 and 8 (p = 0.944), but both are statistically different from the groups 2, 3 and 9. All groups studied presented two or more failure mode and the fractures predominating are the cohesive in the hybrid layer. It was observed that the groups that showed the highest bond strength (Groups 1 and 8) were the ones with the highest percentage of cohesive resin / dentin fractures type. It was concluded that sodium hypochlorite significantly reduced the bond strength to pulp chamber dentin. The bond strength reestablishment on compromised NaOCl-treated dentin do not depended on the sodium thiosulfate concentration when it is used for 5 and 10 min. After applied for 1min, 5% sodium thiosulfate is able to restore the bond strengths to NaOCl-treated dentin (AU) | |
| FAPESP's process: | 11/05302-0 - In vitro evaluation of the influence of the use of sodium thiosulfate as antioxidant agent on bond strength to dentin treated with intracoronary sodium hypochlorite |
| Grantee: | Ana Carolina Pimentel Corrêa |
| Support Opportunities: | Scholarships in Brazil - Master |