MECHANISMS OF FORMATION OF WEDGE SHAPED DEFECT BY ABFRACTION AND ITS RESTORATIVE MRTHIDS.

这个测试的目标是确定生物力学因素和压力诱导的神经质在这些区域之间的关系，并调查更有效的恢复方法。通过脂肪加载一个提取的人类上层预聚器固定在死亡的角度到45 °的长轴的一个长轴。Repeated stress （10.0 Kgf/2.5 Kgf） at 4 Hz was applied the buccal cusp of the tooth up to 6 x10 ^6 cycles in 37℃ DW using a servo-hydraulic machine。形态学变化使用SEM下的精确复制品观察到，裂纹网络的发展约为1.2毫米，在CEJ周围观察到的像素，因为周期的数目增加了，裂纹网络的数目增加了。在另一只手上，一个薄薄的层掉了下来，打开了牙科管在DEJ下的4x 10^6个循环中被人们所熟知。Furthermore，生长的裂缝型裂缝被发现在冠状牙齿上。这些发现可能会支持。压力诱导的理论。从累积脂肪压力的累积中提取的微型裂缝可以作为初始贡献者，形成一个中枢性的形成。根据抽象法进行的治疗以获得长期成功的治疗，恢复材料他们自己应该是所需的生物机械可接受的特征学; Higher Fracture Toughness （K_1c），它显示了高的Fracture Resistance和较低的弹性模块，因为它可以补偿粘合剂界面上的剪切压力。Furthermore是一种具有高级粘性抵抗力的粘合剂接口的形成，即在牙科粘合剂系统上，增加混合层的宽度，增加了充分的单体渗透到去表面化牙科的前面，增加了单体的转换率，增加了单体可能对粘合剂接口的增强功能限制的增强。

The aims of this examination are to identify the relationships between the biomechanic factor and stress-induced cervical lesion by abfraction, and investigate more effective restorative methods at these regions.Artificial formation of cervical lesion by fatigue loadingAn extracted human upper premolar was fixed in die at an angle of 45゜ to the long axis of the tooth. Repeated stress (10.0Kgf/2.5Kgf) at 4Hz was applied the buccal cusp of the tooth up to 6 x 10^6 cycles in 37℃ DW using a servo-hydraulic machine. Morphological changes were observed using precision replica under SEM.The development of a crack network about 1.2 mm in width was observed on the cementum along the CEJ.As the number of cycles increased, the number of crack networks increased. On the other hand, a falling off a smear layer and opening of dentinal tubules were recognized on the gingival dentin under the DEJ at 4 x 10^6 cycles. Furthermore, growth of cleavage-type cracks was observed at the coronal dentin. These findings may support. stress-induced theory. The micro-cracks on the cementum and dentin resulting from the accumulation of fatigue stress may act as the initial contributor to the formation of cervical lesion.Treatment of cervical lesion by abfractionIn order to obtain long-term success for cervical restoration, restorative materials themselves should be required biomechanically acceptable characteristics ; higher fracture toughness (K_1c) that exhibits high fracture resistance and lower modulus of elasticity that can compensate for shear stress at adhesive interface. Furthermore, the formation of adhesive interface with superior fatigue resistance should be desired.On dentin adhesive system, an increase of width of hybrid layer, sufficient monomer penetration up to the front of demineralized dentin and an increase of conversion rate of monomer might contribute to the improvement in fatigue limit of the adhesive interface.