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


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Research & Development, Ivoclar Vivadent AG, FL-9494 Schaan, Liechtenstein. norbert.moszner@ivoclarvivadent.com
Norbert
N
Moszner
Alexandros
A
Gianasmidis
Simone
S
Klapdohr
Urs Karl
UK
Fischer
Volker
V
Rheinberger
D001672:Biocompatible Materials / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D004548:Elasticity; D005898:Glass / Q000737:chemistry; D006801:Humans; D008027:Light; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry; D063225:Organically Modified Ceramics; D018583:Pliability; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D012821:Silanes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors; D014783:Viscosity; D014867:Water / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry
D001672:Biocompatible Materials; D003188:Composite Resins; D003432:Cross-Linking Reagents; D003764:Dental Materials; D008689:Methacrylates; D063225:Organically Modified Ceramics; D011109:Polymethacrylic Acids; D012821:Silanes; D014867:Water; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; D015040:Zirconium; C028541:zirconium oxide