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KMID : 0358920050320030481
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Journal of the Korean Academy of Pedodontics
2005 Volume.32 No. 3 p.481 ~ p.490
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EFFECT OF INCREMENTAL FILLING TECHNIQUE ON THE POLYMERIZATION SHRINKAGE OF COMPOSITE RESIN
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Kim Hyo-Suk
Lee Nan-Young
Lee Sang-Ho
Oh You-Hyang
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Abstract
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The aim of this study was to investigate the relationship between the C-factor and shrinkage strain values of composite resin and examine the strain values in different incremental filling techniques. The strain gauge method was used for measurement of polymerization shrinkge strain.
Experiment was divided two step. In a first experiment, we compared with strain value in three different depth (2mm, 3mm, 4mm) and microhardness of each samples after 24hours were measured. In a second experiment, we examined the strain values in five different filling techniques(Group 1: bulk filling, Group 2: oblique incremental filling, Group 3: horizontal incremental filling, Group 4: vertical incremental filling, Group 5: lining of flowable resin and bulk filling)
The results of the present study can be summarized as follows:
1. Composite resin in acrylic molds showed the initial expansion at the early phase of polymerization.
2. Contraction stress was not revealed significant difference between depth of 2mm and 3mm(P＞0.05).
3. Contraction stress in sample of 4mm was showed the lowest value(P＜0.05).
4. Microhardness of specimen was revealed more difference between upper and lower surface in depth of 4mm than 2 and 3mm(P＜0.05).
5. Lining of flowable resin and bulk filling (Group 5) was showed the lowest contraction stress, Group 2 and 3 was showed the highest contraction stress(P＜0.05).
On the basis above results, the stress that result from the polymerization shrinkage, when incremental curing techniques are used, showed that there is no advantage in incremental placement and curing.
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KEYWORD
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Composite resin, Contraction stress, Incremental filling technique, C-factor
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