Effect of Chemical Application on the pulp of Irradaited Tooth@

Objectives: It has been reported that a denatured layer of dentin that is formed after Er: YAG laser irradiation reduces the resin bond strength. Application of chemicals on that layer of dentin before the adhesive composite resin system has been used to restore the resin bond strength. The purpose of the present study was to clarify the effect of the application of chemicals on the pulp before the conventional composite resin filling. Methods: Twenty-three adult dog teeth were used in vivo. Prototyped Er: YAG laser device (Morita Co., Japan) was used to prepare a black class V cavity in dentin with contact tip under water spray. The condition of laser irradiation was 100 mJ/pulse, 10 pulse/sec, with a wavelength 2.94 micrometer. The diameter of contact tip was 600 micrometer. After cavity preparation, the teeth were treated with K-etchant gel for 30 seconds and AD gel for 90 seconds (RN group; n=13), or with 5% glutaraldehyde aqueous solution for 20 seconds (GA group; n=10). Each tooth was rinsed with water and air dried. Then they were treated with a self-etching primer and bonding and filled with a composite resin. After 7 days all animals were sacrificed and histopathological examinations of the dental pulp were performed. Results: No serious pathological changes in the dental pulp were observed in either group, and satisfactory results were obtained in most cases. Conclusions: These results indicate that the chemical applications given to the RN and GA groups are safe to the pulp before conventional composite resin filling.