1. Introduction to: cavity varnish, liners and bases
DA 122
Dental Materials

2. Uses Varnish, liners and bases are used for:
Prevention of irritation from metal restorations
Sedating an irritated pulp
Providing thermal insulation

3. Determining use
Use of varnish, liners and bases depend on the following factors:
1. Depth of the tooth prep
Shallow prep-goes into enamel only
Cavity varnish only
Medium prep-goes into dentin but not near pulp
Cavity varnish and liner
Deep prep-goes into dentin near the pulp
Cavity liner, base and varnish
2. Type of restorative material used
Varnish not used under composite resins

4. Treatment of Cavity Preparations
Ideal
Minimal dentin and enamel removed
Beyond ideal
Dentin restored with base
The ideal cavity preparation is that in which very little dentin and enamel are removed and no base is needed.
The beyond-ideal preparation requires restoration of some dentin. This preparation requires a base and amalgam, ZOE, polycarboxylate, glass ionomer, or composite materials are used.

5. Treatment of Cavity Preparations
Near-exposure
Restoration occurs close to pulp
Exposed pulp
Can vitality of tooth be saved
The cavity with a near-exposure requires a restoration that will be close to the pulp.
More precautions must be taken first a liner is placed and then two layers of varnish are placed.
After the varnish layer a cement vase is applied.
Preparation for the exposed pulp cavity may require endodontic treatment to save the vitality of the tooth.

6. Placing Cements, Bases, and Liners
Treatment of cavity preparations
Varies with amount of enamel and dentin removed and how near the prep is to the pulp

7. Treatment of Cavity Preparations
Ideal
Minimal dentin and enamel removed
Beyond ideal
Dentin restored with base
The ideal cavity preparation is that in which very little dentin and enamel are removed and no base is needed.
The beyond-ideal preparation requires restoration of some dentin. This preparation requires a base and amalgam, ZOE, polycarboxylate, glass ionomer, or composite materials are used.

8. varnish Copal cavity varnishes. Brand name: Copalite No mixing
Applied to walls and floor of cavity prep
Applied with cotton pellet held in cotton pliers
Applied to shallow prep

9. Liner Calcium hydroxide; brand name: Dycal
Mix equal parts of catalyst and base
Mix for 10 seconds with ball-tip applicator
Mixture should be thin and creamy
Pass to dentist to apply to tooth
Sets in 1-2 minutes

10. base Applied in thick layer (like putty) between tooth and restoration
Protects pulp from:
Chemical irritation
Temperature changes
Electrical protection
Mechanical injury

11. Cements used as bases Zinc phosphate Zinc oxide and eugenol (ZOE)
Insulating base
Zinc oxide and eugenol (ZOE)
Low strength base
Polycarboxylate
High strength base