On the slippery slope of ceramics and composites

Teeth still fail and therefore often require restorative treatment. The two most widely used tooth-colored restoratives are resin-based composites and glass-ceramics, both having different mechanical properties and their own practical advantages and disadvantages. This thesis tries to contribute in a number of laboratory studies towards a clearer indication for both materials.
Chapter 2 shows an overview of current indirect restoration materials, of which veneered ceramic restorations are most prone to fracture and monolithic ceramic restorations the least. The Young’s modulus plays an important role in the load to failure (LtF) of a restoration and probably for glass-ceramics also the internal roughness.
In chapter 3, the influence of thickness of the restoration is shown. For glass-ceramics a quadratic increase of the LtF with an increasing thickness is seen, while the LtF of composites is relatively independent of its thickness. This makes composites more reliable in low thicknesses and ceramics in high thicknesses.
In chapter 4, a fatigue test confirmed the significant influence of substrate on the LtF of both composite and ceramic at 1mm thickness, because composites performed better on dentin and ceramics on enamel.
Chapter 5 displays the detrimental effect of internal roughness on the LtF of glass-ceramics. However, when the ceramics were bonded to the substrate the negative effect of roughness disappeared and the LtF increased significantly.
Chapter 6 shows that the bonding of glass-ceramics to dentin can be improved by a retention groove. But for composite restorations, this groove had no significant effect on the bond strength and even a negative effect on the internal stresses.