边缘设计对全锆冠强度、密合性和边缘质量影响的体外研究进展

In vitro research progress of the effects of margin designs on the fracture strength,marginal discrepancy and margin quality of monolithic zirconia crowns

固定修复体的边缘是修复体与预备体唯一与口腔环境发生连通的区域。修复体边缘设计包括边缘形态及边缘厚度,合适的边缘设计对固定修复体的性能和临床表现均有影响。随着高强度美学氧化锆陶瓷的发展,无饰瓷的完全解剖形态氧化锆冠(简称全锆冠)的应用日益广泛。全锆冠常采用肩台边缘或凹槽边缘设计以增加颈部厚度,降低崩瓷和断裂风险。由于刃状边缘更利于牙体硬组织的保存,因此在全锆冠的边缘设计中,刃状边缘被越来越多的医生采纳。目前临床尚未就全锆冠的边缘设计达成共识。本文通过对近年来,不同边缘设计对全锆冠的抗折强度、边缘密合性及边缘质量影响的体外研究进行回顾分析,发现无论采用何种边缘设计,全锆冠的抗折强度及边缘密合性均能满足临床需求。相比减材制造工艺,新型增材制造工艺初步展现出制作高边缘质量全锆冠的潜力,但是边缘设计对采用新型增材制造工艺制作的全锆冠性能的影响还缺少广泛深入的研究。未来需要进一步开展临床研究,对照分析采用不同边缘设计的全锆冠的修复效果,为全锆冠的边缘设计提供循证依据。

Margin of the dental fixed prosthesis is the only area where the prosthesis and the preparation are connected to the oral environment.Both morphology and thickness should be considered for margin designs.Different margin designs have been proven to have effects on various of properties and clinical performance of the fixed dental prosthesis.With the improvement in the mechanical properties and aesthetics of zirconia ceramics,full-contour monolithic zirconia crowns have become popular in recent years.The monolithic zirconia crowns are always designedas shoulder or chamfer margins which can strengthen the cervical region of crowns and reduce the risk of chipping and fracture.Meanwhile,knife edge,also known as feather edge,has also been adopted for the monolithic zirconia crowns since it could furtherly reduce the amount of tooth preparation and preserve more tooth tissue than other margin morphologies.Until now,no consensus on the margin designs of the monolithic zirconia crowns has been reached yet.This paper presents a review of recent in vitro studies about the effects of margin designs on fracture strength,marginal discrepancy,and margin quality of monolithic zirconia crowns.In conclusion,the fracture strength and marginal discrepancy of all monolithic zirconia crowns with various kinds of margin morphologies and thicknesses could meet the clinical requirements.Compared with subtractive manufacturing process,the new additive manufacturing process shows the potential of improving margin quality.However,there is a lack of extensive research about the effect of margin designs on the performance of monolithic zirconia crowns fabricated by the new additive manufacturing process.Further clinical studies are needed to compare the performance of full-contour monolithic zirconia crowns with different margin designs so as to provide evidence for the margin designs in clinical practice.