THE MICROLEAKAGE OF LIGHT-CURED GLASS LONOMER RESTORATIVE MATERIALS IN CLASS V CAVITIES

제 5급와동에서 광중합 그래스 아이오노머 수복물의 미세변연누출에 관한 연구

The purpose of this study was to evaluate the microleakage of light cured glass ionomer restorative materials in class 5 cavities. In this in vitro study, class 5 cavities were prepared on buccal and lingual surfaces of forty extracted human premolars and molars on cementum margin. These specimen were randomly divided into four groups of 10 each : Group 1 was Fugi II (control), Group 2 was Fugi II LC, Group 3 was Vitremer, and Group 4 was Dyract. Group 2 was also divided once more into 2 groups of 5 each : Group 2-1 was pretreated with dentin conditioner and Group 2-2 was not. All teeth were restored according to the manufacturer's instructions. After 500 thermocycling between $5^{\circ}C$ and $55^{\circ}C$, the 40 teeth were placed in 2 % Methylene blue dye for 24hr, then rinsed with tab water. The specimen were embedded in clear resin, then sectioned buccolingually through the center of restoration with a low speed diamond saw. The dye penetration on each of the specimen were then observed with a stereomicroscope at 20. The results of the study were statistically analyzed using the Student-Newman-Keuls Methods and the Mann-Whitney Rank Sum Test. Tooth restorative interfaces were evaluated using SEM analysis. Results were as follows, 1. Compared to conventional glass ionomer restoratioqs, all light cured glass ionomer restorations were fairly resistant to microleakage (P<0.05). 2. Groups 3 (Vitremer) and Group 4 (Dyract) were found to be the most resistant, Group 2 (Fugi II LC) fairly resistant, and Group 1 (Fugi II) least resistant to microleakage(P<0.05). 3. No significant differences were found between Group 2-1 and Group 2-2 (P>0.08). 4. With the backscattered SEM analysis, the degrees to which tight bonding occurred were also observed in all the groups except for Group 1. Group 4 showed the highest degree of tight bonding than any other materials used in this study.