Question: what is the difference between filled and unfilled resin?
Answer: Unfilled resins are the softest of all restorative materials (low wear resist- ance - no filler) 3. ... These unfilled acrylic resins have been replaced by filled resins (also called composite resins). A filled resin is one in which an inorganic inert filler (usually silica or quartz) has been added to the resin matrix.