- 作者：J. David Eick ; Shiva P. Kotha ; Cecil C. Chappelow ; Kathleen V. Kilway ; Gregory J. Giese ; Alan G. Glaros ; Charles S. Pinzino
- 关键词：Dental matirx resins and composites ; Siloranes ; Cationic polymerization ; Stress reduction ; Mechanical properties ; Tetraoxaspiro[5.5]undecanes
- 刊名：Dental Materials
- 出版年：2007
- 出版时间：August 2007
- 年：2007
- 卷：23
- 期：8
- 页码：1011-1017
- 全文大小：288 K
To evaluate properties of silorane-based resins and composites containing a stress reducing monomer.
Methods
Resin mixtures and composites were formulated containing (a) a developmental stress reducing monomer [TOSU; Midwest Research Institute]; (b) Sil-Mix (3M-ESPE); (c) photo cationic initiator system. Standard BISGMA/TEGDMA resin (B/T) and composite (Filtek Z250) were used as controls. Polymerization volume change was measured using a NIST mercury dilatometer and polymerization stress using an Enduratec mechanical testing machine. Three point bend tests determined flexural elastic modulus, work of fracture, and ultimate strength (ADA 27; ISO 4049). Fracture toughness was measured using ASTM E399-90. Four groups of resins and composites were tested: Sil-Mix, methacrylate standard, and Sil-Mix with two addition levels of TOSU. An ANOVA was used and significant differences ranked using Student–Newman–Keuls test (α = 0.05).
Results
Polymerization stress values for resins containing TOSU were significantly less than the other materials. Polymerization shrinkage values for Sil-Mix formulations were significantly less than for B/T, but were not different from each other. TOSU-containing formulations generally had somewhat lower mechanical properties values than Sil-Mix or B/T. Polymerization stress values for Sil-Mix-based composites were significantly less as compared to Z250. The 1 wt. % TOSU composite had the lowest stress. No difference between composite groups was noted for fracture toughness or work of fracture. For ultimate strength, the 5 wt. % TOSU formulation differed significantly from Z250. All Sil-Mix formulations had elastic modulus values significantly different from Z250.
Significance
The ability of TOSU to reduce polymerization stress without a proportional reduction in mechanical properties provides a basis for improvement of silorane-based composites.