Full text
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| Author(s): |
Cristiane Franco Pinto
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba |
| Defense date: | 2010-00-00 |
| Examining board members: |
Maria Betania de Oliveira Garcia;
Renato Hermann Sunfeld;
Mário Alexandre Coelho Sinhoreti;
Paulo Henrique dos Santos
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| Advisor: | Marcelo Giannini |
| Abstract | |
The aim of this study was to evaluate adhesive systems, mineralized dental tissues (enamel and dentin) around restorations and the bonding formed by adhesives and dental structures in conditions of cariogenic challenge in situ and in vitro. This study used dental blocks (enamel/ dentin) from bovine teeth, which were restored with adhesive systems and a resin composite. For the in situ study: volunteers (n=11) wore intra-oral appliance containing 2 dental fragments without restoration (enamel or dentin) and six dental blocks with restorations made with self-etching primers Clearfil Protect Bond (PB) or One-up Bond F Plus (OP) (in two phases) and the Filtek Z350 composite: The cariogênico challenge was performed in two phases of 14 days (each phase with one adhesive). The volunteers dropped 20% sucrose solution 8x/day and used fluoridated dentifrice 3x/day. After each phase, the biofilm was collected and analyzed. The samples were analyzed by cross-sectional microhardness and polarized light microscopy (PLM) to determine the demineralization depth. For the in vitro study, bovine were prepared and bonded in enamel and dentine with Clearfil Protect Bond (PB) or One-Up Bond F Plus (OP) and restored with Filtek Z-350 composite resin, according to the groups: 1- PB without CC; 2- PB with CC; 3- OP without CC; 4- OP with CC. Restored teeth were sectioned in order to obtain sticks for microtensile bond strength or slabs for transmission electron microscopy. The specimens were submitted to pHcycling, which consisted of DE (8h/day) and RE (16h/day) cycles at 37ºC during days. Microhardness analysis showed that the enamel and dentin around restorations PB had higher values in superficial depths, and the PLM showed that PB resulted in lower demineralization depth than OP. The biofilm investigation indicated that PB produced lower number of bacterial colony of Streptococcus totais and mutans in enamel. The results showed that the pH-cycling regimen did not affect the bond strength to enamel or dentin for both adhesives; however, the bond strength to dentin was higher for PB. The adhesives produced hybridization and no gaps formation in both dental tissues. In conclusion, PB adhesive may result in lower enamel demineralization around restoration and higher microhardness in superficial depths. In some conditions, PB adhesive reduced the number of bacterial colony. Although the adhesives in enamel formed similar bonded interfaces, PB produced higher bond strength to dentin than OP. (AU) | |