During the complete denture restoration process, accurate impression making is a crucial step for achieving good denture retention. With the increasing popularity of intraoral scanning technology in fixed restoration, the use of intraoral scanning technology in complete denture restoration for edentulous jaw has also been developed. This article systematically reviews the research progress and application of intraoral scanning of edentulous soft tissue, focusing on difficulties in intraoral scanning of edentulous jaws, scanning accuracy, clinical application effects, as well as precautions involved. The aim is to provide references for clinical application.

In fixed prosthodontics, clear exposure of the preparation margin is the prerequisite for obtaining accurate digital impressions and improving the marginal fit of restorations. To resolve the issues associated with the cord retraction technique, such as pain, acute injury, and prolonged procedural time, this study proposes a new technology for intraoral digital impression taking with pneumatic gingival retraction. The new scanning head blows a high-speed airflow that instantaneously separates the free gingiva, locally exposing the subgingival preparation margin. Combined with the farthest point preservation stitching algorithm based on the distance from the normal vector and high-speed laser scanning photography, it achieves global preparation edge data and gingival reconstruction, realizing painless, non-invasive, and efficient precise acquisition of the preparation margin. Using this new technique, a patient with a full porcelain crown restoration on a posterior tooth was treated. The digital impression revealed a clear margin of the preparation, and the crown made from this data has a good marginal fit.