【摘要】 由于陶瓷美观且成本较低,烤瓷熔附金瓷冠和全瓷冠是临床中治疗牙体缺损与牙体缺失最为常用的修复体,但瓷层的脆裂仍然是人造牙冠破坏的主要形式。参照磨牙结构和尺寸,利用独特的工艺制作了磨牙剖面试件,设计了加载装置,利用钨钢球触压模拟了口腔中的咀嚼载荷,在微型实验机准静态触压加载的同时,用CCD电视摄像机实时采集试件受载变化过程序列图;采用了二维数字图象相关法分析了烤瓷熔附金瓷冠和全瓷冠中微裂纹产生、演化及主要的破坏过程,确定了微裂纹产生时临界载荷大小和人造冠的破坏形式。更多还原

【Abstract】 Porcelain-fused-metal (PFM) and all-ceramic crowns are most commonly used in clinical application due to esthetic view and low cost. However, the porcelain rapture is still a main failure when crowns are subjected to occlusal loads because of the herent brittleness. The experimental investigation was carried out to explore the fracture mechanism of crowns. Based on the actual size and structure of the posterior molar, sectioned molar specimens along lingual-facial direction were manufactured with both PFM and full dental ceramics. The occlusal load was simulated by Hertzian contact load with tungsten carbide spheres, and an imaging system at the random time acquired sequential images when the sectioned specimen was loaded. Digital image correlation (DIC) was applied to detect the initiation of crack at the onset of crown fracture. The results indicate that the dominant fracture are owing to the radial cracking underneath the loading zone and debonding at the shoulder zone of the crown for full ceramic crowns, while conic cracking is still the main failure mode for PFM crowns.更多还原