Alginate Impressions vs IOS Optical Scanners Using Reverse Engineering Technology: A Comparative Study.

Purpose: this study aims to compare the precision and accuracy of traditional alginate impressions and digital optical impressions taken by second-year dental students using reverse engineering technology. The null hypothesis posits no significant difference in the accuracy between the two methods when performed by inexperienced operators.

Materials and methods: Twenty dental students performed 128 impressions: 64 traditional alginate impressions (Group A) and 64 digital impressions using a intraoral scanner (Group B). The impressions were analyzed and compared to reference models created by an expert operator. Data was captured using reverse engineering software (Geomagic Control X), and precision was evaluated through 3D and point-by-point analyses. Statistical analyses, including paired t tests and the Wilcoxon signed-rank test, were conducted to compare the deviations from the reference model.

Results: The digital impressions demonstrated superior accuracy compared to traditional alginate impressions, with significantly smaller deviations from the reference model. Digital impressions consistently exhibited higher precision and trueness, rejecting the null hypothesis. Statistical significance was found at key points, with p-values below 0.05 for all comparisons.

Conclusions: This study demonstrates that digital impressions provide significantly greater accuracy and precision than traditional alginate impressions, with lower deviations and higher reproducibility. The findings highlight the dimensional instability of alginate impressions and reinforce the advantages of digital intraoral scanning for standardization and consistency in clinical practice. Intraoral scanners provide more precise and accurate impressions than traditional methods, even when used by inexperienced operators. This study supports the integration of digital impression techniques into dental education to enhance student proficiency and improve clinical outcomes.