Ceromer crown의 교합면 두께에 따른 압축 파절 강도의 비교
The compressive fracture strength of ceromer crown by the difference of occlusal thickness
구강과학- 전남대학교 2001년 13권 2호 p.246 ~ 257
김지연, 양홍서,
소속 상세정보
김지연 ( ) - 전남대학교 치과대학 보철학교실
양홍서 ( ) - 전남대학교 치과대학 보철학교실
KMID : 0988420010130020246
Abstract
This study investigated the compressive fracture strength of Targis ceromer crown by the difference of occlusal thickness on a maxillary first premolar. Control group was a castable IPSEmpress allceramic crown with occlusal thickness of 1.5mm constructed by layered technique. Experimental groups were Targis crowns having different occlusal thicknesses of 1.0 mm, 1.5 mm,
2.0mm, 2.5mm, respectively. The classification of Targis group is T10, T15, T20, T25 AND T15N (for nothermocycling and occlusal thickness of 1.5mm). Ten samples were tested per each group. Except occlusal thickness, all dimension of metal die is same with axial inclination of 10˚and marginal width 0.5mm chamfer. All crowns were cemented with Panavia F and thermocycled 1,000 times between 5℃ and 55℃ water bath with 10 sec dwelling time and 10 sec resting time. The compressive fracture strength was measured by universal testing machine.
The results were as follows:
1. Fracture strength was increased as the occlusal thickness increased : compressive fracture strength of Group T10, T15, T20, T25 was 66.65±4.88 kgf, 75.04±3.01 kgf. 87.07±7.06 kgf and 105.03±10.56 kgf, respectively.
2.When comparing material, Targis crown had higher fracture strength than IPS Empress crown : the mean compressive strength of group T15 was 75.04±3.01 kgf and the value of group Control was 37.66±4.28 kgf.
3. Fracture strength was decreased by thermocycling : the compressive fracture strength of T15 was 75.04±3.01 kgf, which is lower than 90.69±6.88 kgf of group T15N.
4. The fracture line of crowns began at the loading point and extended along long axis of tooth. IPS-Empress showed adhesive failure pattern whereas Targis had adhesive and cohesive failure.
In the SEM view, stress was distributed radially from loading point and the crack line was more prominent on Targis crown.
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