Effect of surface conditioning and storage time on the bond strength of orthodontic brackets to lithium disilicate ceramic
| Autor: | Paxon, Jonathan |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Druh dokumentu: | Text |
| Popis: | The effect of different surface conditioning procedures on bracket bond strength to lithium disilicate ceramic were investigated after 30 min, 24 h and 6 months of water storage. Brackets were bonded to 300 IPS e.max samples (Ivoclar Vivadent). Five surface conditioning procedures were tested: 15 seconds 37% H₃PO₄; 20 seconds 9.5% hydrofluoric acid (HF); 60 seconds 9.5% HF; 60 seconds 9.5% HF plus a low-viscosity enamel bonding agent; 20 seconds non-thermal plasma (NTP) only. All samples were further treated with a silane coupling agent prior to bonding with an orthodontic resin cement and were stored in distilled water at 37°C for 30 minutes, 24 hours and 6 months before testing the shear bond strength. Results showed that bond strengths increased from 30 minutes to 24 hours and then decreased at 6 months. At 30 minutes and 24 hours, HF etching for 60 seconds followed by enamel bonding agent exhibited significantly higher bond strength than all other groups. At 6 months, all groups etched with HF exhibited similar bond strengths that were significantly greater than both H₃PO₄ and NTP surface conditioning. Etching with HF resulted in increased adhesive residue on the sample surface after debonding compared to treatment with NTP or H₃PO₄. The results suggest that surface treatment with 20 to 60 second 9.5% HF etching times yields stable bond strengths, as the bond strengths did not significantly reduce after 6 months. Dentistry, Faculty of Graduate |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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