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

缺损楔形缺损的形成机制及其修复性研究。

• 批准号: 09671971
• 负责人: HANAOKA Koji
• 金额: $ 1.92万
• 依托单位: KANAGAWA DENTAL COLLEGE
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09671971/
• 关键词: ABFRACTION; WEDGE SHAPED DEFECT; GLASSIONOMER CEMENT; FRACTURE TOUCHNESS; RESIN COMPOSITE; HYBRID LAYER; ADHESIVE FATIGUE DURABILITY; DENTIN ADHESION; 破壊靱性

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.

本研究旨在探讨生物力学因素与应力性牙颈部损伤的关系，并探讨在这些部位更有效的修复方法。疲劳载荷下牙颈部损伤的人工形成取离体上颌前磨牙，与牙体长轴成45 °角固定于模具中。使用伺服液压机在37℃ DW中以4 Hz对牙齿的颊侧尖施加重复应力（10.0Kgf/2.5Kgf），最多6 x 10^6次循环。在扫描电镜（SEM）下，观察到牙骨质沿着CEJ方向形成了一个宽度约为1.2 mm的裂纹网络，随着循环次数的增加，裂纹网络的数量也随之增加。另一方面，在DEJ下4 x 10^6次循环时，在牙龈牙本质上发现玷污层脱落和牙本质小管开口。此外，在冠状牙本质中观察到劈裂型裂纹的生长。这些发现可能会提供支持。压力诱发理论牙骨质和牙本质上因疲劳应力积累而产生的微裂纹可能是导致颈椎病变形成的始动因素。颈椎病变的切削治疗为了使颈椎修复获得长期成功，修复材料本身应具有生物力学可接受的特性;较高的断裂韧性（K_1c）表现出较高的抗断裂性，较低的弹性模量可以补偿粘接界面处的剪切应力。在牙本质粘接系统中，增加混合层的宽度，使单体充分渗透到脱矿牙本质的前端，提高单体转化率，可能有助于提高粘接界面的疲劳极限。

项目成果

KOJI HANAOKA, DAISUKE NAGAO, KUNIHARU MITSUI, AKIRA MITSUHASHI, SHINICHIRO SUGIZAKI AND TOSHIO TERANAKA: "A BIOMECHANICAL APPROACH TO THE ETIOLOGY AND TREATMENT OF NONCARIOUS DENTAL CERVICAL LESIONS"THE BULLETIN OF KANAGAWA DENTAL COLLEGE. 26-2. 103-113 (

KOJI Hanaoka、DAISUKE NAGAO、KUNIHARU MITSUI、AKIRA MITSUHASHI、SHINICHIRO SUGIZAKI 和 TOSHIO TERANAKA：“非龋性牙颈部病变的病因学和治疗的生物力学方法”神奈川牙科学院通报。

長尾大輔: "象牙質接着システムの接着特性について-剪断接着強さと破壊面の検討-"神奈川歯学. 33. 40-51 (1998)

长尾大辅：“关于牙本质粘合系统的粘合性能 - 剪切粘合强度和断裂表面的检查 -”神奈川牙科科学 33. 40-51 (1998)。

KUNIHARU MITSUI, KOJI HANAOKA, YASUNORI TSUBOTA AND TOSHIO TERANAKA: "FATIGUE CHARACTERISTICS OF DENTIN ADHESIVE SYSTEMS - INFLUENCE OF POLYMERIZATION SYSTEM ON ADHESIVE"ADHESIVE DENTISTRY. 17-3. 220-226 (1999)

Kuniharu Mitsui、KOJI Hanaoka、Yasunori TSUBOTA 和 Toshio teranaka：“牙本质粘合系统的疲劳特性 - 聚合系统对粘合的影响”粘合牙科。

長尾大輔,花岡孝治、寺中敏夫: "象牙質接着システムの接着特性について-剪断接着強さと破壊様式の関係-" 神奈川歯学. 33・1. 40-51 (1998)

长尾大辅、花冈幸二、寺中俊夫：“关于牙本质粘合系统的粘合特性——剪切粘合强度与破坏模式之间的关系”神奈川牙科 33・1（1998）。