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Effects of Glass Fiber Layering on the Flexural Strength of Microfill and Hybrid Composites
Author(s) -
ERONAT NESRIN,
CANDAN ÜMIT,
TÜRKÜN MURAT
Publication year - 2009
Publication title -
journal of esthetic and restorative dentistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.919
H-Index - 60
eISSN - 1708-8240
pISSN - 1496-4155
DOI - 10.1111/j.1708-8240.2009.00259.x
Subject(s) - flexural strength , materials science , composite number , composite material , glass fiber , universal testing machine , fiber , distilled water , ultimate tensile strength , chemistry , chromatography
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 × 2 × 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°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. CLINICAL SIGNIFICANCE Glass fiber reinforcement of both hybrid and microfill resin composite materials may be a clinical option in otherwise unfavorable clinical conditions, such as large cavities and/or where bruxism is in present restorative dentistry.