전장용 복합레진의 2축굽힘강도에 미치는 Thermal Cycling의 영향 = Effect of Thermal Cycling on the Strength of Veneering Resin Composites for Crown

다국어 초록 (Multilingual Abstract)

Effect of Thermal Cycling on the Strength of the veneering resin composites for crown. Four commercially available resin composites were used. Disc specimens were fabricated in the teflon mold giving a specimen size of 12mm in diameter and 1mm in thickness. In order to investigate the deterioration by thermal cycling test, biaxial flexure strength and Knoop hardness were measured. Thermal cycing test was conducted at 15 second dwell time each in 5℃ and 55℃ baths. Biaxial flexure test was conducted using the ball-on-three-ball method at the crosshead speed of 0.5mm/min, and Knoop hardness measurement was made under 25g load for 15 seconds. Fracture surfaces were examined by scanning electron microscope.
The results obtained were summarized as follows;
1.The strength data were fit to single-mode Weibull distribution. Weibull modulus values of the DC and ET groups decreased after thermal cycling test, but the AG and TG groups increased.
2.The highest biaxial flexure strength of 169.96MPa was observed in the ET group after the thermal cycling test, and the lowest value of 52.54MPa was observed in the DC group. Biaxial flexure strengths showed the significant differences in each resin composite group(p＜0.05).
3.Knoop hardness number of ET group after the thermal cycling test was the highest(148.79kg/㎟) among the resin composites, while that of the DC group was the lowest(23.56kg/㎟). Knoop hardness numbers showed the significant differences between the ET group and others, and also between the AG or TG group and DC group(p＜0.05).
4.Observation of fracture surfaces revealed that cracks initiated from the center point where the maximum tensile stress was occurred and then propagated in the conical shape.

목차 (Table of Contents)

• 서론
• 재료 및 방법
• 1.실험재료
• 2.실험방법
• 결과
• 고찰
• 결론