Accuracy of implant positions recorded by intra-oral implant scanning and extra-oral implant scanning protocols for both open- and closed-tray conventional implant impression techniques in Class I Kennedy classification models.

Document Type : Original Article

Authors

1 MSc Student, Prosthodontics Department, Faculty of Dentistry, Modern University of Technology and Information, Cairo, Egypt

2 Lecturer, Prosthodontics Department, Faculty of Dentistry, Cairo University, Egypt

3 Professor, Prosthodontics Department, Faculty of Dentistry, Cairo University, Egypt

10.21608/edj.2025.407332.3568

Abstract

Aim: The aim of this study was to compare the accuracy of implants’ positions between intra- and extra-oral scanning protocols in mandibular bilateral free-end saddle partially edentulous models in terms of angular deviation.
Methodology: This in vitro study included 5 class I Kennedy classification mandibular models with 3 implants on both sides that were placed fully guided using a computer-guided surgical stent. Scan bodies were then screwed using hand torque to these implants. Then an extraoral scan was taken to these models using a desktop scanner to generate a digital reference model. After that direct digital impressions were obtained by an intra-oral scanner then an open-tray followed by closed-tray (CT) impression techniques were made for conventional impressions. Stone casts from conventional impressions were then digitized using the same desktop scanner. Each digital STL file of digital and conventional impressions was superimposed over the reference STL file to enable comparison and finally the accuracy was assessed by calculating the angular deviations by using planning software (BlueskyBio). Statistical comparisons were carried out between the studied groups using a one-way analysis of variance (ANOVA) test.

Results: The results showed that the angular deviation mean for the (CT) was the highest (2.1197 o ±0.790 o) while the (IOS) was the lowest (0.792 o±0.0835 o).

Conclusion: Within the limitations of this current study, the results showed that there was statistically significant difference in angular deviations among superimposed scan bodies between conventional and digital implant impression techniques, where the intraoral scans showed the least deviation values.

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