수종 복합레진에 있어서 효소 역할에 의한 표면 경도와 조도 변화에 관한 연구
The study of change in surface hardness and textres of composlte resin due to enzymatic action
소속 상세정보
김미리 이명종
KMID : 0362319950200010193
Abstract
The purpose of this study is to investigate a possible contribution of nonspecific esterases, which occur in the oral cavity, to the degradation of ester bonds in polymethacrylates. One of the problems connected with the use of composite resins
for
restorations is their inadequate resistance to wear. It has been shown that methacrylate hydrolysis can be catalyzed by enzymes and that a carboxylic hydrolase (porcine iver esterase) catalyzed the hydrolysis of several mono-and dimethacrylates.
The
softening effect on a BISGMA/TEGDMA polymer induced by hydrolase will accelerate the in vivo wear of the polymer.
Porcine liver esterase (EC 3.1.1.1) in 3.2 mol/L (NH4)2 SO4 was obtained from Sigma Chemical Company. The esterase activity of one unit is defined as the amount of enzyme capable of hydrolyzing 1㎛ol ethyl butyrate per min at pH 8.0 AT 25℃.
Phosphate
buffer, 10mmol/L, pH 7.0, was made by adjustment of a solution of Na2HPO4 with H3PO4. Composite resins used in this study are Silux Plus, Z-100, Durafil VS, and Prisma APH.
Cylindrical specimens, 14mm in diameter and 3mm thick, of Silux Plus, Z-100, Durafil VS, Prisma APH were polymerized under the celluloid strip. 60 specimens were divided into 2 groups. One group was emersed only in buffer solution, the other
group
was
emersed in buffer and enzyme solution. Silux Plus and Z-100 were divided into 2 subgroups, one subgroup was cured only Visilux 2. And the other subgroup was cured Visilux 2 and Triaid II.
Thereafter, specimens were polished to its best achievable surface according to manufacture's directions. The Vickers hardness of the specimens was measured after 1, 2, 4, 7, 9, 15, 50 days. The solutions were changed after each measurement.
Composite
resin surfaces were evaluated for the surface roughness with profilometer(α-step 200, Tencor instruments, USA) after 1 and 50 days. And then surfaces of specimens were pictured with stereosopy after 1 and 50 days.
@ES The results were as follows.
@EN 1. The surface hardness of Silux plus, durafil VS, and Prisma APH were decreased with time. But, the surface hardness of Z-100 was not decreased.
2. The surface hardness of all composite resins was not decreased.
3. Composite resins, which were light-cured by Visilux 2 and concomitantly baked by oven, showed more hardened surface than light-cured by Visilux 2 only.
4. Significant surface changes were occured in Silux plus after esterase treatment.
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