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

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

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

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.

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.

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

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.

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

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

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

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