CHEMICAL DEGRADATION OF LIGHT-CURED DENTAL COMPOSITE RESINS

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Journal of the Korean Academy of Pediatric Dentistry 2001;28(3):403-411.
Published online August 31, 2001.

CHEMICAL DEGRADATION OF LIGHT-CURED DENTAL COMPOSITE RESINS

수종 치과용 광중합형 복합레진의 화학적 분해

양규호, 최남기, 박미란, 박은혜

전남대학교 치과대학 소아치과학교실 및 치의학 연구소

Abstract

The aim of this study was to evaluate the resistance to degradation of four commercial composite resins in an alkaline solution. The brands studied were Unifil(GC, Japan), Palfique(Tokuyama Japan). Definite Degussa-Huls AG, Germany). Revolution(Kerr, U.S.A.). Preweighed discs of each brand were exposed 0.1N NaOH solution at 60℃. After 14 days they were removed, neutralized with HCl, washed with water and dried. Resistance to degradation was evaluated on the basis of following parameters: (a) mass loss(%) - determined from pre-and post-exposed specimen weights; (b) Si loss(ppm) - obtained from ICP-AE analysis of solution exposed to specimens; and (c) degradation depth(μm) - measured microscopically (SEM) from polished circular sections of exposed specimens. The results were follows: 1. The mass loss of Unifil was 3.21%, it was the highest of materials. But, there was no significant difference among the materials. 2. The degree of degradation layer depth was 107.69\sim47.40μm, the sequence of the degree pf degradation layer depth was in descending order by Unifil, Palfique, Revolution, Definite. There was significant difference among the materials except Palfique and Definite. 3. The Si loss of Paltique was 8940.0ppm, it was the highest. There was significant difference among the materials, except Revolution and Definite(p<0.05). 4. The correlation coefficient between mass loss and degradation depth was relatively high(r = 0.06, p<0.05). 5. There was no significant coefficient correlation between Si loss and mass loss, and/or the degree of degradation layer depth and Si loss. 6. When observed with SEM, destruction of bonding is observed between resin matrix and filler. Above results suggested that the hydrolytic degradation is considered as evaluation factor of composite resins.

Key Words: Composite resins, Chemical degradation, Alkaline solution