CAD/CAM陶瓷髓腔固位冠修复无髓后牙的研究进展

Research progress in the restoration of non-medullary posterior teeth with ceramic pulp cavity-retained crowns

无髓后牙即指行根管治疗后大面积缺损的后牙,因其缺少牙髓组织的营养供应,容易变脆,导致牙齿劈裂的风险大大增加。因此需要对其行进一步的修复治疗,以降低牙齿劈裂的风险,延长使用寿命。随着近年来微创修复理念的发展以及数字化技术的不断进步,计算机辅助设计与制造(computer-aided design/manufacturing,CAD/CAM)技术切削制作的髓腔固位冠在临床上已被越来越多的应用于根管治疗后大面积缺损后牙的冠修复治疗。临床上常用于制作陶瓷髓腔固位冠的陶瓷材料有玻璃陶瓷、氧化锆陶瓷及树脂基陶瓷等,上述材料各有其优缺点:氧化锆陶瓷材料已被广泛用于临床,其弹性模量高达210GPa,但其仍存在不可再修复性的风险;釉锆与传统氧化锆具有相似的弹性模量,并且美观性更佳,但目前对其性能研究较少;相较于氧化锆陶瓷材料,玻璃陶瓷及树脂基陶瓷较少出现不可再修复性风险,但二者弹性模量远低于氧化锆陶瓷。此外,髓腔固位冠的边缘设计亦会影响其远期效果;并且牙体预备方式如咬合面高度、面厚度、髓腔固位深度、轴壁外展度等均会对髓腔固位冠的修复效果产生影响。本文就CAD/CAM陶瓷髓腔固位冠用于修复无髓后牙时的适应证、临床注意事项、材料的选择、边缘设计、牙体预备等方面展开综述,以期为临床上无髓后牙的修复提供有价值的参考信息。

Unmedullated posterior teeth are those with large defect after root canal treatment.Due to the lack of nutritional supply of pulp tissue,the posterior teeth tend to become brittle and the risk of splitting is greatly increased.Therefore,further prosthetics are needed to reduce the risk of tooth splitting and prolong the service life.With the development of minimally invasive repair concept and the continuous progress of digital technology in recent years,computer-Aided Design/Manufacturing,the endocrown made by CAD/CAM technology has been more and more widely used in the crown repair of large defect after root canal treatment.Clinically,ceramic materials commonly used to make ceramic endocrowns include glass ceramics,zirconia ceramics and resin-based ceramics.Each of the above materials has its own advantages and disadvantages:Zirconia ceramics have been widely used in clinic,and its elastic modulus is up to 210 GPa,but it still has the risk of being irredeemable;Zirconium glaze has similar elastic modulus to traditional zirconia and has better aesthetics,but its properties are less studied at present.Compared with zirconia ceramics,glass ceramics and resin-based ceramics have less risk of non-repairability,but their elastic modulus is much lower than zirconia ceramics.In addition,the edge design of endocrown also affects its long-term effect.In addition,tooth preparation methods such as occlusal surface height,maxillofacial thickness,retention depth of pulp cavity,axial wall abduction and so on all affect the restoration effect of pulp cavity retention crown.In this paper,the indications,clinical considerations,material selection,edge design and tooth preparation of the CAD/CAM ceramic endocrowns were reviewed in order to provide valuable reference information for the clinical restoration of medullary posterior teeth.