Comparison of the Clinical Accuracy of Digital and Conventional Dental Implant Impressions

European Journal of Prosthodontics and Restorative Dentistry (2020) 28, 173–181

Dental Implants Prosthodontics Digital Impression Intraoral Scanner Conventional Impressions

Vygandas Rutkunas *
(Prof. Dr., DDS, PhD)

Agne Gedrimiene *
(PhD student)

Rimas Adaskevicius ^
(Prof., PhD)

Nadin Al-Haj Husain ‡
(Dr. med. dent.)

Mutlu Özcan §

(Prof. Dr., DDS, DMD, PhD)

Address for Correspondence
Vygandas Rutkunas *
Email: vygandasr@gmail.com
* Vilnius University
University of Bern

‡

University of Zurich

§

^ Department of Electrical Power Systems, Faculty
of Electrical and Electronics Engineering, Kaunas
University of Technology, LITHUANIA

Comparison of the Clinical
Accuracy of Digital and
Conventional Dental Implant
Impressions

The aim of this study was to compare the clinical accuracy of digital and conventional dental implant impressions. Two types of implant impressions were made for each case, namely a conventional open-tray impression and a digital implant impression (DII) using a Trios IOS. Master casts were scanned using a D800 laboratory scanner and STL files were retrieved from conventional and digital workflows to be exported for comparison. The distance between center points, angulation, rotation, vertical shift, and surface mismatch of the scan bodies were evaluated and compared between conventional and digital impression techniques. Comparing digital and conventional impression techniques the following factors showed statistically significant differences: distance (73.7±75 µm), angulation (0.42±0.3º), and surface mismatch of scan bodies. The difference in conventional and digital impression techniques as regards to angulation and distance between the implants were associated with distance, angle, and vertical shift differences in scan. The mismatch of the scanned surface of scan bodies was twice higher for the intraoral scanner group. Clinicians should therefore control the implant suprastructures clinically and also using casts (e.g. printed casts) when a digital scan is planned.

Conventional elastomeric dental implant impressions and plaster cast production has been a standard procedure in implant-supported prothesis fabrication for a long time. Digital impressions can now be used as an alternative procedure. Despite considerable improvement in intraoral scanners (IOS), their application is still limited in multiple implant or edentulous situations. The scanning of larger edentulous areas for fixed partial dentures, scanning strategy, number of implants, and properties of scan bodies are among the factors that can lead to clinically significant inaccuracies.1-3 An accurate implant impression is a key factor to achieve long-lasting, functional, passive and esthetic restorations. During the process of making impressions and fabricating casts and restorations, errors tend to build-up and a certain degree of inaccuracy is unavoidable. Since dental implants are virtually immobile, ill-fitting restorations can potentially cause mechanical complications (screw loosening, chipping of veneering ceramic) and biological complications (periimplantitis, mucositis), which are widely discussed in the literature.1

Received: 05.01.2020 Accepted: 06.05.2020

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