Author/Authors :
Tavangar ، Maryam نويسنده Dept. of Operative and Esthetic Dentistry, Faculty of Dentistry, Guilan University of Medical Sciences, Rasht, Iran. , , TayefehDavalloo، Reza نويسنده Dept. of Operative and Esthetic Dentistry, Faculty of Dentistry, Guilan University of Medical Sciences, Rasht, Iran. , , Darabi، Farideh نويسنده , , Karambin ، Mahsa نويسنده Dentist, Rasht, Iran. , , Kazemi ، Reza نويسنده Dept. of Reconstructive Sciences, University of Connecticut Health Center, School of Dental Medicine, Farmington, USA. ,
Abstract :
Statement of the Problem: Polymerization shrinkage stress in composite restorations may lead to microleakage. Clinical methods such as using low-shrinkage composites have been suggested to overcome this problem; however, there are controversies about their efficiency in decreasing the microleakage.
Purpose: This in vitro study was conducted to compare the microleakage of two low-shrinkage resin composites with a conventional one.
Materials and Method: Fifty class V cavities of 2.5×3×2 mm (depth× length× width) were prepared in the buccal surfaces of intact bovine incisor teeth with the incisal margin on the enamel and gingival margin on the cementum. The teeth were randomly divided into 5 groups. In group 1, Clearfil APX (conventional) with SE Bond was used in 2 layers (Kuraray; Japan). In group 2, GC Kalore (low –shrinkage) with GC UniFil Bond was applied in one layer (GC Company). In group 3, the material of group 2 was applied in two layers. In group 4, FiltekP90 (low –shrinkage) with P90 System adhesive was applied in one layer (3M ESPE). In group 5, the materials of group 4 were applied in two layers. The samples were thermocycled and immersed in 0.5% fuchsin solution for 24h. The restorations were sectioned in buccolingual direction. Then they were evaluated for microleakage by using a stereomicroscope and scored as 0, 1, 2, and 3 and then Kruskal-Wallis test was used (p < 0.05).
Results: The groups were not significantly different regarding the microleakage in the coronal and cervical margins (p < 0.423 and p < 0.212, respectively); however, the Filtek P90 yielded the best results. In all groups, except group 5 (p= 0.018), the cervical margins had greater microleakage than the coronal margins.
Conclusion: The results suggested that low-shrinkage resin composites may not reduce the marginal microleakage. The proper use of conventional resin composites may offer comparable clinical results.
