Evaluation of the accuracy (trueness, precision) and processing time of different 3-dimensional CAD software programs and algorithms for virtual cast alignment

Abstract

Objectives

This in vitro study aimed to evaluate the impact of different alignment algorithms and CAD software programs on alignment accuracy (trueness and precision) and processing time.

Methods

A mandibular typodont was digitized using a laboratory scanner (L2i) to obtain a reference standard tesselletion language (STLr) file. It was then scanned with an intraoral scanner (Primescan) and digitally duplicated ten times (n = 10). Each scan was aligned with the STLr using 42 combinations of 3D CAD software and alignment algorithms. The tested software programs included Blender for Dental, BlueSkyPlan, Dental CAD App (Exocad), Medit Design, NemoSmile, and Meshmixer. Alignment accuracy (trueness and precision) and processing time were recorded using Python software (v3.8). Statistical analysis was performed with a two-way ANOVA test (α = 0.01) to identify overall differences, followed by a post hoc Tukey Honestly Significant Difference test (α = 0.05) to establish rankings.

Results

Significant differences in alignment accuracy were observed based on the software and algorithm used, affecting both trueness (p<.01) and precision (p<.01). Processing time also varied significantly (p<.01). Post hoc analysis identified the optimal algorithm for each software, revealing variations in trueness, precision, and processing time among the optimal versions. Medit Design achieved the best overall performance by combining high accuracy with the fastest processing time, while Meshmixer exhibited the lowest accuracy due to its lack of advanced algorithms.

Conclusions

The choice of CAD software and alignment algorithm significantly influences alignment accuracy and efficiency. Best-fit and section-based provided the best results, offering valuable insights into the optimization of digital workflows in prosthodontics.

Clinical significance

Alignment protocols must be tailored to the specific CAD software program used, as no universal protocol was effective across all tested software. Optimizing alignment protocols reduces errors, enhances prosthodontic outcomes, and improves the reliability and efficiency of clinical and laboratory workflows, ultimately ensuring better patient care and treatment success.