A STUDY ON THE CHANGES IN POLYMERIZATION OF LIGHT-ACTIVATED COMPOSITE RESIN WITH VARIOUS EXPOSURE TIME AND DISTANCE

Ahn, Myung-Ki; Jeong, Tae-Sung; Kim, Shin

Journal of the Korean Academy of Pediatric Dentistry 2001;28(2):293-299.
Published online May 31, 2001.

A STUDY ON THE CHANGES IN POLYMERIZATION OF LIGHT-ACTIVATED COMPOSITE RESIN WITH VARIOUS EXPOSURE TIME AND DISTANCE

Myung-Ki Ahn, Tae-Sung Jeong, Shin Kim

Department of Pediatric Dentistry, College of Dentistry, Pusan National University

광중합형 복합레진의 중합시간과 거리에 따른 중합도의 변화

안명기, 정태성, 김신

부산대학교 치과대학 소아치과학교실

Abstract

The aim of this study was to evaluate the effect of the distance of the light tip to the surface of restoration and exposure time on the polymerization of surface and 2mm below the surface of light-activated composite resins. Two light-activated composite resins were used. From the experiment, the following results were obtained. 1. Relative light intensity rapidly decreased when distance of the light tip to the surface of material is more than 2mm(p<0.05). 2. In all groups, microhardness was increased according to the increase of relative light intensity and exposure time(p<0.05). 3. The distance of the light tip to the surface of restoration and exposure time more affected 2mm below the surface rather than the surface(p<0.05). 4. Although exposure time was increased, difference of microhardness of the 2mm below the surface with the distance of the light tip to the surface of restoration was relatively high in Z100 between below 4mm and other groups and Z250 between below 2mm and other groups(p<0.05).

Key Words: Light-activated composite resin, Exposure time, Distance, Microhardness