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Objectives:
Reduced polymerisation shrinkage and an associated
increase in synergy between the tooth/restoration interface may be realised
if novel monomer systems are developed which do not employ dimethacrylate
monomers. Method: The mean bi-axial flexure strengths (BFS) and
Weibull moduli (m) of an experimental oxirane RBC, EXL 580 and two commercially
successful dimethacrylate RBCs were investigated. Volumetric shrinkage
and degree of conversion were recorded using a gas pycnometer and FTIR
analysis for 0.1, 0.5, 1, 4, 24 and 48h immersion in a waterbath maintained
at 37±1°C, respectively. Results: A significant decrease in the
BFS and associated elastic moduli of EXL 580 was observed after 0.1, 0.5
and 1h compared with Z250 and Z100. EXL 580 provided significantly less
polymerisation shrinkage after each period of immersion.
Conclusions:
Consequently, the improved mechanical and physical
properties of the oxirane-based composite investigated in the current
study may ultimately increase marginal integrity of such a restoration
compared with dimethacrylate based systems. This work was co-funded by
3M ESPE and EPSRC Case Award 00303435. |
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