Accuracy and precision of two intraoral scanners in oral implantology – In vitro analysis of the lower jaw model with 4 scan bodies

Abstract

Background : Intraoral digital impressions in implantology have become a popular alternative to conventional impressions. The scanning of scan bodies on dental implants is required to use computer-aided design computer-assisted manufacture processes for implant prosthetics.Limited informations are available about the accuracy and precision of intraoral scanners when they are applied in implantology, especially by edentulous jaws. Information from everyday clinical work show same difficulties and limitations.Aim/Hypothesis : The study has two goals. First goal is to compare the accuracy and precision of two intraoral scanner in a fully edentulous model of lower jaw with for implants. Second goal is to determine the impact of dentist ' s skills on scanning results. Material and Methods : One stone model were prepared, representing totally edentulous mandible with four implant analogues (Straumann®) and polyether-ether-ketone (PEEK) scan bodies screwed on. The model was digitized with an industrial scanner (Atos Core 135) used as a reference and with two intraoral scanners (Trios®; Omnicam®). Four dentists scanned the model used the recommended scan protocol, each was taken five scans using two intraoral scanners. STL datasets were loaded into GOM Inspect 3D software (2019.rev). All scans were superimposed over the reference model using a best fit algorithm. Deviations were measured at three selected points on the top of each scanbodies. Intraoral scans were superimposed on the reference model, to evaluate accuracy. All scans superimposed on each other within groups, to evaluate general precision.Results : SPSS program was used. Mann-Whitney test was applied for comparing the difference in accuracy ( P < 0.0001) and Kruskal Wallis for precision ( P < 0.05). Statistically significant difference in accuracy was found. Trios® scanner showed higher accuracy. Kruskal Wallis test ( P < 0.05) showed statistically significant difference in precision between reference model and Trios® ( P = 0.005) and reference model and Omnicam® ( P = 0.01). There was statistically significant difference in results for accuracy between each dentist ( P < 0.05) for Trios® and Omnicam®. The difference in scanning precision between the dentist was found. ANOVA test showed results for deviations between selected points on scan bodies. As a qualitative analysis, the 3D deviations between the reference model and intraoral scans were illustrated in a colorcoded gradient maps. Conclusion and ClinicalImplications : Accuracy and precision of two intraoral scanners in the process of scanning edentulous model with for implants show that Trios® has a higher precision and accuracy compared to Omnicam®. Despite their differences, obtained values shows that both scanners are clinically acceptable. The study indicate that the dentist ' s skill has important impact on the measurement results. Further studies are needed to validate the accuracy and precision of these scanners under clinical conditions.