A STUDY ON THE CHANGES IN DEGREE OF CONVERSION OF DUAL-CURE RESTORATIVE MATERIALS WITH TIME-ELAPSE

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Journal of the Korean Academy of Pediatric Dentistry 1999;26(3):554-563.
Published online August 31, 1999.

A STUDY ON THE CHANGES IN DEGREE OF CONVERSION OF DUAL-CURE RESTORATIVE MATERIALS WITH TIME-ELAPSE

이중중합 수복재의 시간경과에 따른 중합도 변화

양철호, 김신, 정태성

부산대학교 치과대학 소아치과학교실

Abstract

For the purpose of elucidating the polymerization modes of dual-cure restorative materials and comparing them with single-cure restorative materials, a study was performed on the light-cured composite resin, dual-cure composite resin, dual-cure glass ionomer cement and chemical-cure glass ionomer cement. By measuring the microhardness of each material at 0mm, 1mm and 3mm depth during initial 24 hours with predetermined interval, the state of polymerization and degree of conversion was indirectly evaluated for each material, and obtained results are as follows : 1. All of four materials tested showed significant increase in microhardness after 24hrs compared with just after curing starts. 2. In all materials except Ketac-fil, there showed a significant difference in microhardness between each depth at each time interval. 3. In the test of lap time till final curing for each material, the polymerization process was revealed to last longer in the dual-cure type materials than in single-cure type materials at 3mm depth. Based on the results above, it was demonstrated with materials of dual-cure mode that the degree of conversion increases by successive curing reactions even in the deeper layers where sufficient curing light is impermeable.

Key Words: Polymerization, Microhardness, Dual cure