Abstract
Kinetic cavity preparation is a kind of cavity preparation method using a highspeed stream of carried aluminium oxide particles propelled by air pressure.
A significant defect of Kinetic cavity preparation systems is damage to carvo-surface sound tooth enamel. The purpose of this study was to establish a protective method for the carvo-surface sound tooth enamel during air-powder abrasive system cavity preparation, using protective varnish.
A total of 21 extracted human primary teeth were used for this experiment. Protect Varnish (Kuraray Co.) was applied to the tooth surface in single, double and triple coats in each of 7 cases respectively. The Kinetic instrument KCP-2001 J (Denics Co.) was used for cavity preparation. Class V cavities were prepared on the border areas of varnish coated and intact tooth surfaces, with 27 μm aluminium oxide particle and 7 kg/cm2 air pressure at a 1 to 2 mm distance at a right angle to the tooth surface. After removal of the varnish with a supersonic washer, specimens were dried and gold plated with ion-spatter, following which the cavity margin enamel was observed through a SEM.
The following conclusions were obtained.
1. Tooth surface enamel where coated with varnish appeared intact. However, tooth surface enamel without varnish coating appeared rough.
2. Protective varnish was found to provide a protective effect for carvo-surface sound enamel. It seemed likely that kinetic energy was absorbed by the soft varnish coating, thereby protecting the enamel.
3. Double and tripre coats of Protective varnish are effective for protection of carvo-surface sound tooth enamel.
4. In the group without protective varnish, the carvo-surface margin exhibited a round shape. While in the group with protective varnish the carvo-surface margin remained in a right angle form. Protective vernish was found to promote a sharp edge at the carvo-surface margin, during kinetic cavity preparation.
