Role Of Liners In Restorative Dentistry
Cavity liners are cement coatings of minimal thickness that are applied to the prepared cavity when the remaining dentin thickness is adequate.
Purpose of Cavity Liners
- Cavity Liners serve as a physical barrier to ingress bacteria or bacterial products.
- Cavity Liners provide therapeutic effects, i.e. antibacterial, anticarcinogenic, and pupal anodyne effects.
- Cavity Liners provide a barrier for the protection of pulp from residual reactants which diffuse out of the restoration.
- They prevent oral fluids which can penetrate leaky restoration from reaching pulp via dentin.
- When they are used under metallic restorations they contribute to some electrical or thermal insulation.
Classification of Cavity Liners
- Thin film liners (1 to 50 µm)
- Solution liners (Varnish; 2 to 5 µm)
- Suspension liners [Zinc oxide (Type IV)/calcium hydroxide; 20 to 25 µm]
- Thick liners (200 to 1000 µm)
- Type III GIC.
Supplied Cavity Liners
- The solution is in bottles.
- Powder and liquid.
- Single light-cured paste.
Composition of Cavity Liners
Suspension of calcium hydroxide in an organic liquid such as methyl ethyl ketone or ethyl alcohol. Acrylic polymer heads or barium sulfate, monoflorophosphate.
Properties of Cavity Liners:
- Liner neither possesses mechanical strength nor provides any significant thermal insulation.
- The calcium hydroxide liners are soluble and should not be applied at the margins of restorations.
Manipulation of Cavity Liners:
Cavity liners are fluid in consistency and can be easily flawed or painted over dentinal surfaces. The solvent evaporates to leave a thin film residue that protects the pulp.
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