Intraoral Scanner Technologies: A Review to Make a Successful Impression

Abstract

To overcome difficulties associated with conventional techniques, impressions with IOS (intraoral scanner) and CAD/CAM (computer-aided design and manufacturing) technologies were developed for dental practice. The last decade has seen an increasing number of optical IOS devices, and these are based on different technologies; the choice of which may impact on clinical use. To allow informed choice before purchasing or renewing an IOS, this article summarizes first the technologies currently used (light projection, distance object determination, and reconstruction). In the second section, the clinical considerations of each strategy such as handling, learning curve, powdering, scanning paths, tracking, and mesh quality are discussed. The last section is dedicated to the accuracy of files and of the intermaxillary relationship registered with IOS as the rendering of files in the graphical user interface is often misleading. This overview leads to the conclusion that the current IOS is adapted for a common practice, although differences exist between the technologies employed. An important aspect highlighted in this review is the reduction in the volume of hardware which has led to an increase in the importance of software-based technologies.

The effect different substrates have on the trueness and precision of eight different intraoral scanners

“…The reflectivity, refraction index, and translucency (RR&T) of a given material can change the amount of light received by an IOS sensor which can affect the quality of 3D data captured . As a pattern of light is projected from the scanner onto a surface, only light reflected back into the sensor can be used to calculate the location of all data points of interest (POI) . The different tissues of the teeth and dental materials have different RR&T .…”

Effect of scan substrates on accuracy of 7 intraoral digital impression systems using human maxilla model

“…Furthermore, digital impressions can lead to cost savings in space, record portability and facilitated collaboration between clinicians and laboratories . However, IOS devices are not without limitations, and current literature suggests sensitivities to intraoral fluids, scanning technique and variation in substrate may affect the accuracy of IOS data acquisition …”

“…Studies conducted in an industrial application highlight the importance of recognizing the effects of RR&T when designing a 3D imaging sensor . For instance, if an IOS projects a microscopic grid of lasers onto a tooth surface, it will interpret the pattern reflected into the sensor and calculate the location of all data points of interest (POI) . Not only do different tissues of the teeth have varying RR&T, but natural dentin has been shown to have a varying refractivity index, depending on the orientation of tubules at the scan location .…”

Laminate veneers: Preplanning and treatment using digital guided tooth preparation

“…Alternatively, when small amounts of enamel preparation are needed, a two‐step approach can be adopted. Vertical preparation has been tested in vitro and in vivo with high‐strength ceramics and lithium disilicate for full crowns and veneers with marginal fit similar to conventional preparation and survival rates over 95% from 4 to 12 year …”