Research progress on the precision of digital impressions used in implant-supported fixed prostheses

Since the digital impression technique has already been widely used in dental therapy, it has grown into a popular option among implant practitioners. The advantages of the digital impression technique are as follows: better experience for patients during the treatment; less chair-side time consumption; and reliability in making the precise impression. Thus, we reviewed the relevant factors that impact the precision of the digital impression technique and introduced its influence mechanism through an evidence-based method that was based on analyzing in vitro and in vivo literature published within the previous 5 years, with a focus on such considerations as relevant factors to dentists, digital impression systems, patients, and the environment. A review of the literature showed that the main factors that have a large influence on impression precision are imaging techniques and the software for the impression system. However, due to the development of impression systems that are restricted at scientific and technological levels, impression precision is affected by multiple factors, such as scanning techniques, dentist operation proficiency, material and contours of scanbodies, patient conditions, and ambient light. Dentists are advised to scientifically choose the impression system, limit ambient light and adopt direct techniques that could enhance impression precision. In the future, the development of impression systems could reduce the systematic errors, decrease the operating complexity of dentists, and improve impression precision.