| 0339 Gap Localization in Bonded Composite and Amalgam restorations | ||
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S.B. GEIGER1, Y. WIND1, and E. KLEIN2, 1 Tel-Aviv University, Tel Aviv, Israel, 2 Weizmann Institute of research, Rehovot, Israel Objectives: The objective of the present study was to evaluate the effect of the restorative material in bonded composite or amalgam restorations on gap formation. Methods: Class V cavities were prepared in 78 premolar teeth, and six types of bonding interfaces were formed using the following materials ( by 3M ESPE): 1) Single-Bond and Rely-X™ ARC (uncured), 2) Single-Bond and Rely-X™ ARC (cured), 3) Single-Bond and Filtec™Flow, 4) RelyX™, 5) Single-Bond only, and 6) Control (no bonding or cement). Amalgam and Composite (Z-100) were applied as restorations. Samples were examined for dye penetration after thermocycling using light microscope, and further analyzed using a Scanning Electron Microscope equipped with an Energy Dispersive Spectrometer, as well as an Environmental Scanning Electron Microscope. Results: Low levels of microleakage were observed in all bonded restorations with no dye penetration to dentinal tubules, compared to the control group. SEM analysis showed gap formation in bonded composite restorations at the border between the hybrid and the bonding layer. In amalgam restorations the gaps were found between the bonding or cement layer and the amalgam. EDS analysis verified the chemical composition of the different layers examined. Environmental SEM confirmed that gap formation was not attributable to sample dehydration and high vacuum conditions used at the SEM. Conclusions: Gap localization depended on the type of material used for the restoration. In amalgam restorations gaps developed between bonding (or cement) and amalgam, on the other hand, in composite restorations, gap was formed at the border of the hybrid layer. The results suggest that shrinkage stress, developed at the bonded composite restorations, might be the cause of the separation of the bonding layer from the hybrid layer. (Research supported by 3M ESPE) | ||
| Seq #33 - Dental Materials: Material/ Tooth Interface, Toxicity 4:00 PM-6:00 PM, Friday, 27 August 2004 Crowne Plaza Hotel SEDEF III | ||
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