Effects of Glass Fiber Layering on the Flexural Strength of Microfill and Hybrid Composites
Makaleler > Tam Makale · 2009
Yazarlar: NESRİN ERONAT, Uemit Candan, Murat TÜRKÜN
Journal of Esthetic and Restorative Dentistry, SCI Expanded İndekslerine Giren Dergi, Uluslararası, Wos, 2009, cilt 21, ss 171-178
DOI: 10.1111/j.1708-8240.2009.00259.x
Özet
STATEMENT OF THE PROBLEM: In stress-bearing cavities, low fracture resistance adversely affects the longevity of the dental resin composite restorations. PURPOSE: The aim of this in vitro study was to investigate the effect of glass fiber layering on the flexural strength of microfill and hybrid composites. MATERIALS AND METHODS: Flexural test specimens (N = 75) were prepared according to International Organization for Standardization (ISO) 4049 specifications (25 x 2 x 2 mm) by using a standard metallic mold. Materials used and groups were as follows (N = 15): group 1: hybrid composite (Clearfil APX, Kuraray Co.Ltd, Osaka, Japan); group 2: microfill composite (Clearfil ST, Kuraray Co.Ltd.); group 3: hybrid + microfill composite; group 4: woven glass fiber (EverstickNet, StickTech Ltd, Turku, Finland) + hybrid composite; group 5: woven glass fiber + microfill composite. The specimens were stored in distilled water at 37 degrees C for 7 days. Afterward, they were loaded to fracture (1 mm/min) by using a universal testing machine (AG-50 kNG Shimadzu Co., Kyoto, Japan). Flexural strengths were expressed as maximum flexural load per cross-sectional area of the specimen. The results were statistically analyzed with Kruskall-Wallis and Mann-Whitney U tests (p < 0.01). RESULTS: Significant increases in the flexural strength were found for both hybrid and microfill composites when fiber layering was used (group 1: 78 +/- 7 MPa; group 4: 93 +/- 4 MPa) (group 2: 42 +/- 5 MPa; group 5: 64 +/- 4 MPa) (p < 0.01). Flexural strength of fiber-reinforced hybrid composite was significantly higher than the other groups evaluated (p < 0.01). There were no significant differences in flexural strength between microfill/hybrid combination and fiber-reinforced microfill composite (p > 0.01). CONCLUSIONS: Glass fiber layering of microfill and hybrid composites presented higher flexural strength, and veneering of hybrid composite with microfill composite increased the resistance of the restoration.