Abstract: Recently,intraoral digital impression technique has been one of the focus in oral medicine.Compared with the model digital impression technique,the intraoral digital impression technique is convenient,fast,real-time and flexible.It can greatly improve the comfort degree of patients and has obvious advantages over traditional technique.At the same time,intraoral digital impression technique also faces severe challenges of complex oral scanning environment,and the bottleneck problem in optical scanning should be solved urgently to seek new breakthroughs in scanning precision.In this paper,the advantages and limitations of intraoral digital impression technique were listed,and clinical indications were analyzed to guide the clinical application.The principles of the mainstream technique and their current clinical application were introduced to let the readers have more comprehensive understanding for intraoral digital impression technique.

Key words: intraoral scanner, digital dental impressions, triangulation, confocal microscopy, active wavefront sampling