Digital Evaluation of the Positional Accuracy of Implant Scan Bodies in All-On-Four Patients Using Digital Approach—A Controlled Clinical Trial

A BSTRACT Aim: To compare the positional accuracy of the scan body obtained in indirect and direct–indirect digital approaches with that of the direct digital approach. Materials and Methods: Twenty implants were placed, each maxilla of four, using All-On-Four concept in five patients. Three impression techniques have been applied to each patient, namely 1) direct digital approach, 2) indirect digital approach, and 3) direct–indirect digital approach. With the use of specialized 3D inspection and metrology software, the difference in scan body position between the groups was calculated. Results: The average total deviation values for the two groups under examination were 343.15 ± 3.4 μm and 402.79 ± 2.6 μm, respectively. For each of the study groups, the deviation measurement between the superimposed scan bodies revealed statistically significant ( P = 0.006) differences. A statistically insignificant difference between the compared groups was found by the post hoc analysis ( P = 0.006 and 0.014). Conclusion: The direct–indirect digital impression group displayed the least positional accuracy (402.79 ± 2.6 μm). The accuracy of all three digital impression-making approaches in implant dentistry appears to be clinically acceptable and adequate for all types of implant restorations, especially in All-on-Four treatment modality.