Operative dentistry aje qualtrough, jd satterthwaite la morrow, pa brunton

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Chapter 5
posterior teeth it is sensible to consider provision of an indirect
restoration that provides cuspal coverage.
Stronger materials
When any restoration is provided, the main factor to be considered for
choice of material is the functional demands that will be placed on the
restoration and the ability of available material to withstand these
forces. Although amalgam has good compressive strength, it will 
not have sufficient mechanical properties for use in all situations,
especially for very large restorations in posterior teeth subjected to
high loads. It is often necessary to use an alternative material with
more suitable properties, such as gold or ceramic (though ceramics
are generally brittle and weak in tension).
Although there have been rapid and numerous advances in resin-
based restorative materials for aesthetic restorations, the mechanical
properties of these are still markedly inferior to that of amalgam. In
situations in which demand for an aesthetic result is high and when
direct resin-based restorations would not have sufficient strength or
wear properties, an indirect restoration may be utilised. Resin composite
inlay restorations made indirectly have the advantage that handling is
easier and technique sensitivity is less with respect to control of poly-
merisation shrinkage. In addition, it is thought that resin composite
inlay restorations made indirectly have mechanical properties super-
ior to similar directly placed materials, as they are polymerised 
under pressure and at a higher temperature so that the degree of con-
version is higher. However, there is little clinical difference in wear
4
.
Alternatively, ceramic inlays may be used, though these restorations
must have enough bulk to provide sufficient strength. Resin com-
posite and ceramic may also be used for cuspal coverage restorations.