الفهرس 
RESEARCH AND EDUCATIONOnly 14 pages are availabe for public view
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Abstract
Digitalization of edentulous areas restored with dental implants is still considered a demanding procedure, mainly because of the lack of fixed reference landmarks, together with an increased inter-implant distance. To overcome such limitations, a geometric device is introduced for purpose of creating areas with non-homogeneous architectures between the implants, and shortening the inter-implant distance with the interposition of solid geometric figures. Also subtractive modifications on intra-oral scan bodies is believed to enhance scanning trueness and overall scanning accuracy.
Aim of the study: The aim of this in vitro study is to evaluate and compare the accuracy of a maxillary complete arch digital implant scan when using a specially designed geometric device with the accuracy of modified scan bodies.
Material and methods: Four implants were placed in an edentulous maxillary model made of porous bone material with polyurethane attached gingiva. Scan bodies were attached to the implants and then digitized with a high precision laboratory scanner to create the reference scan. Round depressions were made on the buccal and palatal surfaces of the scan bodies, and the model was scanned with an intraoral scanner using 4 different scenarios: the model with no geometric device or modified scan bodies (ND-NM), device only without modified scan bodies (D-NM), no device but with modified scan bodies (ND-M), and device with modified scan bodies (D-M). Each group was scanned 10 times for a total of 40 scans. Trueness and precision were evaluated using inspection software to measure the 3D surface deviation.
Results: Both the geometric device and SB modifications had a significantly significant effect on trueness and precision (P<0.001). Regarding trueness, group D-M had the lowest mean and standard deviation (0.158 ±0.028 mm) in contrast with group ND-NM, which had the highest deviation (0.282 ±0.038 mm). In terms of precision, group D-M showed the lowest mean and standard deviation (0.134 ±0.013 mm), while group ND-NM revealed the highest deviation (0.222 ±0.031 mm). However, no statistically significant interaction was found between the device and modifications regarding either trueness or precision (P>0.05).
Conclusions: Using a specially designed geometric device improved both the trueness and precision of complete arch digital implant scans. The modified SBs had a positive influence on the scanning trueness and precision, and the best accuracy was achieved when using the geometric device and the modified SBs simultaneously.