Evaluation of the accuracy of two full-digital versus half-digital techniques for post-and-core with different root canal entrance diameters

Abstract

Purpose: With the advancement in digital technology, post-and-cores can be produced using full-digital techniques. This study aimed to evaluate the accuracy of two full-digital impression techniques for scanning the post space with different root canal entrance diameters using an intraoral scanner (IOS) (TRIOS 3) with and without a scan post, compared to the half-digital impression technique.

Methods: Standard models of three intact teeth with varying root canal entrance diameters were prepared. Fifteen post-and-core designs per tooth were created using direct IOS and IOS with scan posts, with the half-digital technique as the control. All files were exported as standard tessellation language (STL) files, and the root mean square (RMS) deviations were analyzed between the experimental and control groups. Deviations were measured at standardized points across four regions: the occlusal external, occlusal internal, middle third, and apical third.

Results: No significant differences in the overall RMS were observed among the different root canal entrance diameters (3 mm, 4 mm, and 5 mm) for direct IOS and IOS with scan posts (P > 0.05). However, an independent samples t-test revealed a significant difference (P < 0.05) in both trueness and precision between the two experimental groups, with IOS with scan posts consistently showing lower RMS values.

Conclusions: For post space lengths less than 7.4 mm in single-rooted teeth, both direct IOS and IOS with scan posts can serve as viable alternatives to half-digital techniques. However, in deeper areas, IOS with scan posts are recommended as alternatives to the half-digital technique.