Accuracy of digital and conventional implant impressions in edentulous jaws: A clinical comparative study

This clinical study aimed to evaluate the accuracy of digital and conventional implant impressions in a fully edentulous maxilla and mandible.

A 53-year-old edentulous patient with four maxillary and two mandibular implants was selected. Ten intraoral scans (IOS) and a conventional impression per jaw were taken. Clinically verified upper and lower plaster models were digitized using both optical (reference data, n = 10 per model) and tactile laboratory scanner (n = 10 per model). Accuracy was evaluated by comparing the precision and linear/angular deviations of the implants with the reference data. Statistical analyses were conducted using Student's t-test and Kruskal-Wallis test (α = 0.05).

In the maxilla, the most significant linear deviations exceeding the 100 µm threshold were found with IOS between implants 1-4. In the mandible, all linear deviations remained below 55 µm. Angular deviations between implants after IOS ranged from 0.01° to 0.40° in the mandible and <0.01° to 1.86° in the maxilla. After tactile scanning, linear deviations did not exceed 100 µm threshold (except in one distance) and angular deviations ranged from 0.04° to 0.54° (mandible) and <0.01° to 2.50° (maxilla). The optical scanner demonstrated significantly higher precision (p < 0.001) compared to the IOS and tactile scanner.

Given the significant deviations observed, especially in the maxilla, the optical scanner following conventional impressions remained the preferred method for fully edentulous cases due to its superior accuracy.

IOS could be a viable alternative particularly for shorter distances in the edentulous jaw, although the clinical implications of these deviations need to be investigated in future studies.