Cavity lining materials

CaOH liner Zinc oxide cements GIC/RMGIC

A cavity base is a thicker material typically used for dentine replacement. It is more common in metal restorations A cavity liner is much thinner and used for coating over dentine or over pulp as a cap. Often used when pulpal protection is required

Micro-leakage of some materials leaving gaps between material and tooth surface Some unreacted materials leach toxins which can seep into the pulp Not all restorative materials bond directly to tooth surfaces

Strong thermal stimuli Caries, bacteria and endotoxins Chemical stimuli from unreacted restorative materials Palliative treatment - decrease tooth sensitivity pre-treatment Therapeutic treatment to reduce discomfort form inflammation

Radiopaque - to see difference between liner and tooth Cariostatic - fluoride release to prevent secondary caries Low thermal conductivity and diffusivity High compressive strength Marginal seal and bond to tooth surfaces and restorative materials to prevent micro-leakage Low solubility Biocompatible and non-toxic to tooth tissue Easy to mix and use

• initial pH of 12 so alkalinity means its bacteriocidal • radiopaque • fast setting • ease of use

Irritation to odontoblast layer causing necrosis and tertiary dentine deposition Unstable and soluble Low compressive strength

At close proximity to the pulp as an indirect or direct pulp cap Should be covered with RMGIC

Acid + base reaction of liquid + powder Chelation of ZnO with eugenol, this binds to unreacted ZnO • pros are its a bulk mix with high compressive strength • long working time • provides a white colour and the shade can be matched to tooth material

Brittle and opaque Not cariostatic Not adhesive to tooth surface or restorative materials Exothermic setting Cannot withstand amalgam when used as a liner unless it is modified with resin

Can bond to tooth surface and composite Fully seals dentine tubules Lower thermal conductivity and diffusivity than dentine! - lower post treatment sensitivity Easy to mix and place, light cure too so long working time High compressive strength Most radiopaque

Must etch prior to placing Greatest initial solubility Any unreacted can damage the pulp PCS