Introduction to: cavity varnish, liners and bases

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

5. Treatment of Cavity Preparations • Near-exposure • Restoration occurs close to pulp • Exposed pulp • Can vitality of tooth be saved

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

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 • Insulating base • Zinc oxide and eugenol (ZOE) • Low strength base • Polycarboxylate • High strength base