Bilayered ceramic dental composites with adhesive or reactive bonded interfaces

By close inspection of the well polished cross-sections, two categories of interfaces were classified, namely, adhesive bonding between veneering porcelains and zirconia or alumina cores versus reactive bonding between veneering porcelains and cores of glass infiltrated alumina or lithium disilicate based glass ceramics. Argon ion beam cross-section polishing technique was applied to achieve gentle and fine polishing required for high resolution interfacial characterisation by scanning electron microscopy. The observations suggest that it is desirable to enhance the interfacial reactive bonding in order to avoid delamination in alumina and zirconia based composites.