Reason for loosening of ceramic restorations -

The resin cement forms the weakest link for a ceramic restoration. This was found in an investigation of the de-bonding of resin cementation of zirconia or lithium di-silicate ceramic to bovine dentin.

An evaluation of the radiopacity of composite restorative materials used in Class I and Class II cavities -

The study showed that twelve composites showed radiopacity greater than enamel, for five the radiopacity was lower than that of dentin, and for two materials the radiopacity was between that of enamel and dentin.