Assessment of intraoral scanning technology for multiple implant impressions - A systematic review and meta-analysis

Intraoral scanner (IOS) is a medical device used for capturing direct optical impressions and composed of a handheld camera (hardware), a computer and software. Digital impressions by intraoral scanning have become an increasingly popular alternative to conventional impressions. The aim of this systematic review is to assess the studies regarding the various available technologies for IOS and evaluate the most accurate IOS system for cases with multiple implants and identify the factors that can influence its accuracy.

A comprehensive electronic search was done in online databases, 'Pubmed', 'Google Scholar' and 'Cochrane' based on pre-determined eligibility criteria. In-vitro studies, In-vivo studies and Randomized controlled trials assessing the accuracy of intra-oral scanner technology were selected after thorough screening. The search strategy covered all studies published until February 2019 and yielded a total of 11 articles out of which 8 studies were determined to fulfil the inclusion criteria and were selected for this review. Data extraction from the included studies was conducted by the primary author and reviewed by the second author.

The information collected included sample size and population, study design, intervention, scanning methods, comparisons and outcome measures. 5 out of 8 included studies compared the distance deviation of the acquired scans from the true values while the remaining 3 studies gave trueness and precision values as the outcome variables. A forest plot on scanner precision displayed slightly higher precision levels in the TRIOS scanner compared to the other intraoral scanners.

Despite the limitations this study, it can be concluded that active wavefront sampling is more accurate than the other intraoral scanning technology employed by commercial scanners.