Evaluation of the trueness and precision of complete arch digital impressions on a human maxilla using seven different intraoral digital impression systems and a laboratory scanner

Abstract

Objectives: An impression accuracy study using a cadaver maxilla was performed using both prepared and intact teeth as well as palatal tissue.

Materials and methods: Three crown preparations were performed on a cadaver maxilla. Seven different digital impression systems along with polyvinylsiloxane impressions were used to create digital models of the maxilla. Three-dimensional (3D) files of the experimental models were compared to a master model. The 3D files were overlaid and analyzed using a comparison software to create color coded figures that were measured for deviations between the master and experimental models.

Results: For scanning tooth structure, only the Planscan was significantly less accurate than the rest of impression techniques. No significant differences in accuracy were found between models created using digital impressions and those created from traditional vinyl polysiloxane impressions with cross arch deviations ranging from 18 to 39 μm for each.

Conclusions: Impressions taken using all digital impression systems, save for the Planscan, were able to accurately replicate the tissues of a complete arch human maxilla.

Clinical significance: Studies examining accuracy of digital impression systems have generally been performed on materials other than dental tissues. Optically, materials such as plastic and metal have properties different from enamel and dentin. This study evaluates accuracy of digital impression systems on human dentin, enamel, and soft tissues.

Keywords: CAD/CAM dentistry; digital dentistry; digital impression; fixed prosthodontics; intraoral scanning; scanning accuracy.