Sol-gel materials 2. Light-curing dental composites based on ormocers of cross-linking alkoxysilane methacrylates and further nano-components

• Published in: Dental materials 2008-06, Vol.24 (6), p.851-856
• Main Authors: Moszner, Norbert, Gianasmidis, Alexandros, Klapdohr, Simone, Fischer, Urs Karl, Rheinberger, Volker
• Format: Article
• Language: English
• Subjects: Biocompatible Materials - chemistry; Bisphenol A-Glycidyl Methacrylate - chemistry; Ceramics - chemistry; Composite Resins - chemistry; Cross-Linking Reagents - chemistry; Dental Materials - chemistry; Dentistry; Elasticity; Glass - chemistry; Humans; Light; Materials Testing; Methacrylates - chemistry; Nanoparticles - chemistry; Organically Modified Ceramics; Pliability; Polyethylene Glycols - chemistry; Polymethacrylic Acids - chemistry; Silanes - chemistry; Silicon Dioxide - chemistry; Stress, Mechanical; Temperature; Time Factors; Viscosity; Water - chemistry; Zirconium - chemistry
• ISSN: 0109-5641
• DOI: 10.1016/j.dental.2007.10.004

The objective of this study was to investigate the use of ormocers, which were synthesized from amine or amide dimethacrylate trialkoxysilanes. Ormocers showed improved biocompatibility in dimethacrylate-diluent-free composite restoratives. Selected mechanical properties, such as flexural strength and flexural modulus of experimental composites containing ormocers were investigated. In addition, the influence of methacrylate-substituted ZrO2 clusters and SiO2 organosols on the mechanical properties of composites was studied. The flexural strength and flexural modulus of elasticity were determined according to ISO 4049: 2000. For this purpose, test specimens (2mmx2mmx25mm) of the composites investigated were prepared in stainless steel moulds and light-cured (150mW/cm2, 2x180s). The flexural strength and flexural modulus of elasticity were measured after the samples had been stored in water for 24h at 37 degrees C. While visible light-cured dimethacrylate-diluent-free composite restoratives based on the investigated ormocers showed a similar flexural strength and flexural modulus of elasticity compared to composites that contain only dimethacrylates, their double bond conversion was considerable lower. The simultaneous addition of methacrylate-substituted ZrO2 clusters and SiO2 organosols to the ormocer composite improved the mechanical properties of the composites. Ormocers of amine or amide dimethacrylate trialkoxysilanes enabled the preparation of dimethacrylate-diluent-free composite restoratives. Based on the lower cytotoxicity of the ormocers, the prepared restorative composites should show improved biocompatibility. With the addition of nanoparticles, such as methacrylate-substituted ZrO2 clusters or SiO2 organosols, the mechanical properties of composites can be improved.