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| Author(s): |
Daniel Sundfeld Neto
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba |
| Defense date: | 2016-12-19 |
| Examining board members: |
Luís Roberto Marcondes Martins;
Lucas Silveira Machado;
Marina Di Francescantonio;
Mário Alexandre Coelho Sinhoreti;
Marcelo Giannini
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| Advisor: | Luís Roberto Marcondes Martins |
| Abstract | |
The present study evaluated the influence of previous thermal treatment (PTT) of different hydrofluoric acid (HF) concentrations on the bonding characteristics between a reinforced lithium disilicate glass ceramic (EMX) and resin cement. The study was divided into 3 chapters: Chapter 1) evaluation of different HF concentrations (1%, 2.5%, 5%, 7.5% and 10%) and their interaction with PTT (control group ¿ no PTT; previously heated HF ¿ 70°C; previously heated EMX surface ¿ 85 °C; and the combination of previously heated HF and EMX) on the EMX surface morphology (n=1) and microshear bond strength (?SBS, ?=1 mm) (n=12) between EMX and resin cement; Chapter 2) evaluation of different HF concentrations (5% and 10%) and their interaction with PTT (previously described in Chapter 1) on the EMX surface morphology (n=1) and microshear bond strength (?SBS, Tygon matrices of ?= 0.8 mm) (n=12) between EMX and resin cement; Chapter 3) evaluation of different HF concentrations (5% and 10%) and their interaction with PTT (previously described in Chapter 1) on the EMX surface morphology (n=1) and microtensile bond strength (?TBS, sticks with 1 mm2) (n=10) between EMX and resin cement at 24-hour and after 18 months of water storage. After etching, silane and a thin bonding agent were applied. In Chapter 1, resin cement was inserted into three cylinder-shaped orifices from pre-fabricated matrices and lightcured for 20 seconds. In Chapter 2, five Tygon tubes as matrices were positioned on the EMX surface and the same resin cement was inserted and lightcured for 20 seconds. In Chapter 3, the etched EMX was luted to a resin composite block via dual-cured resin cement. The etched surface morphology analysis revealed the same pattern in the three Chapters: 10% HF presented a higher conditioning effect and PTT enhanced the etching efficacy of lower HF concentrations (1%, 2.5% and 5%). For control groups in Chapter 1, 1%, 2.5% and 5% yielded lower ?SBS values (p<0.05), whereas, after PTT, the values were statistically similar to control groups of 7.5% and 10% HF concentration (p>0.05). Similarly, the ?SBS results of Chapter 2 showed an increase on the ?SBS values after PTT on groups etched with 5% HF (p<0.05). In Chapter 3, 5% HF yielded lower ?TBS than 10% HF in the control groups at both 24-hour and 18-month storage times (p<0.05). The PTT improved the ?TBS values only for 5% HF (p<0.05). The water storage have not negatively influenced on the ?TBS (p>0.05). Both HF concentrations and PTT have influenced on the bonding characteristics between EMX and resin cements, so that lower HF concentrations submitted to PTT were shown to be as effective as higher HF concentrations (AU) | |
| FAPESP's process: | 13/26573-7 - Effects of hydrofluoric acid concentration and thermal treatment on bond strenght to dental ceramic |
| Grantee: | Daniel Sundfeld Neto |
| Support Opportunities: | Scholarships in Brazil - Doctorate |