PRINCIPLES OF INTRAORAL SCANNERS AND MEASUREMENT OF THEIR ACCURACY

Czech version

Authors: P. Hyšpler ¹; T. Dostálová ^2,*
Published in: Česká stomatologie / Praktické zubní lékařství, ročník 125, 2025, 1, s. 13-22
Category: Review Article
doi: https://doi.org/10.51479/cspzl.2025.002

Overview

Introduction and aim: A fully digital workflow is increasingly dominating our surgeries. For small prosthetic reconstructions on teeth or implants, the precision and trueness of certain intraoral scanners are not only sufficient, but significantly better than the conventional technology – dental impression/plaster model. A completely different situation arises with large reconstructions. The aim of this literature review was to summarize the current knowledge on intraoral scanner technologies and their accuracy measurements. Another aim was to evaluate devices and procedures for improving the accuracy of intraoral scans in large fixed prosthetic reconstructions.

Methods: The PubMed/Medline, Scopus, and Embase databases were searched using the following keywords: “Intraoral scanner”, “CAD/CAM”, “Trueness”, “Precision”, “Optical impression”, “Custom-made measuring device”, “Guided implant scanning”, “Continuous scan strategy”. The results were limited to articles published in the English language between 2010 and 2024.

Results: Thirty-seven publications met the inclusion criteria. There are very few articles describing the technology used by currently available intraoral scanners. Twenty-one publications focused on improving the accuracy of intraoral scanning using new procedures or devices. The remainder of the included articles compared the accuracy of intraoral scanners across different products or compared to traditional prosthetic procedures. Most of the older studies comparing the accuracy of intraoral scanners used distance measurements and angular errors. In more recent studies, the method of superimposing surface data obtained by 3D scanners was predominant. Only one study employed the pyramid replacement method with Procrustean analysis.

Conclusion: Articles addressing the principles of intraoral scanners are scarce and rarely found in dental journals. An analysis of the available literature shows that there are multiple options to improve the accuracy of intraoral scanning. These strategies primarily involve optimizing the scanning path and incorporating additional devices to avoid merging errors in the prosthetic workflow. Extraoral scanners and the use of prosthetic lab scanners are especially promising. Reducing the merging error of intraoral scans using different devices probably does not have the potential to ensure the required accuracy.

Keywords:

intraoral scanner, CAD/CAM, trueness, precision, optical impression, custom-made measuring device, guided implant scanning, continuous scan strategy

Sources

1. Logozzo S, Zanetti EM, Franceschini G, Kilpelä A, Mäkynen A.
Recent advances in dental optics – Part I: 3D intraoral scanners for restorative dentistry. Opt Lasers Eng. 2014; 54: 203–221.
doi: 10.1016/j.optlaseng.2013.07.017

2. van der Meer WJ, Andriessen FS, Wismeijer D, Ren Y.
Application of intra-oral dental scanners in the digital workflow of implantology. PLoS One. 2012; 7(8): e43312.
doi: 10.1371/journal.pone.0043312

3. Geng J.
Structured-light 3D surface imaging: a tutorial. Adv Opt Photonics. 2011; 3(2): 128. doi: 10.1364/AOP.3.000128

4. Handbook of biological confocal microscopy, revised edition. James B. ed.
New York and London: Pawley Plenum Press; 1990, 1989.

5. Richert R, Goujat A, Venet L, Viguie G, Viennot S, Robinson P, et al.
Intraoral scanner technologies: a review to make a successful impression. J Healthc Eng. 2017; 2017: 1–9. doi: 10.1155/2017/8427595

6. Schmitt JM.
Optical coherence tomography (OCT): a review. IEEE J Sel Top Quantum Electron. 1999; 5(4): 1205–1215. doi: 10.1109/2944.796348

7. Sanda M, Miyoshi K, Baba K.
Trueness and precision of digital implant impressions by intraoral scanners: a literature review. Int J Implant Dent. 2021; 7(1): 97.
doi: 10.1186/s40729-021-00352-9

8. Alsharbaty MHM, Alikhasi M, Zarrati S, Shamshiri AR.
A clinical comparative study of 3-dimensional accuracy between digital and conventional implant impression techniques.
J Prosthodont. 2019; 28(4): e902–e908.
doi: 10.1111/jopr.12764

9. Fukazawa S, Odaira C, Kondo H. Investigation of accuracy and reproducibility of abutment position by intraoral scanners.
J Prosthodont Res. 2017; 61(4): 450–459.
doi: 10.1016/j.jpor.2017.01.005

10. Nedelcu R, Olsson P, Nyström I, Rydén J, Thor A.
Accuracy and precision of 3 intraoral scanners and accuracy of conventional impressions:
A novel in vivo analysis method.
J Dent. 2018; 69: 110–118.
doi: 10.1016/j.jdent.2017.12.006

11. Ajioka H, Kihara H, Odaira C, Kobayashi T, Kondo H.
Examination of the position accuracy of implant abutments reproduced by intra-oral optical impression. Bencharit S, editor. PLoS One. 2016; 11(10): e0164048.
doi: 10.1371/journal.pone.0164048

12. Piedra-Cascón W, Methani MM, Quesada-Olmo N, Jiménez-Martínez MJ, Revilla-León M.
Scanning accuracy of nondental structured light extraoral scanners compared with that of a dental-specific scanner. J Prosthet Dent. 2021; 126(1): 110–114.
doi: 10.1016/j.prosdent.2020.04.009

13. Pozzi A, Agliardi E, Lio F, Nagy K, Nardi A, Arcuri L.
Accuracy of intraoral optical scan versus stereophotogrammetry for complete-arch digital implant impression: An in vitro study.
J Prosthodont Res. 2023; 68(1): 172–180.
doi: 10.2186/jpr.JPR_D_22_00251

14. Lee SJ, Betensky RA, Gianneschi GE, Gallucci GO.
Accuracy of digital versus conventional implant impressions. Clin Oral Implants Res. 2015; 26(6): 715–719. doi: 10.1111/clr.12375

15. Mangano FG, Hauschild U, Veronesi G, Imburgia M, Mangano C, Admakin O.
Trueness and precision of 5 intraoral scanners in the impressions of single and multiple implants: a comparative in vitro study. BMC Oral Health. 2019; 19(1): 101.
doi: 10.1186/s12903-019-0792-7

16. Son K, Lee WS, Lee KB.
Effect of different software programs on the accuracy of dental scanner using three-dimensional analysis.
Int J Environ Res Public Health. 2021;
18(16): 8449.
doi: 10.3390/ijerph18168449

17. Hyspler P, Urbanová P, Dostalova T. Comparison of the reverse scan technique with an intraoral scanner and the traditional impression technique. J Prosthet Dent. 2024: S0022-3913(24)00583-3.
doi: 10.1016/j.prosdent.2024.08.012.
Epub ahead of print.

18. Mangano FG, Hauschild U, Veronesi G, Imburgia M, Mangano C, Admakin O.
Trueness and precision of 5 intraoral scanners in the impressions of single and multiple implants: a comparative in vitro study. BMC Oral Health. 2019; 19(1): 101.
doi: 10.1186/s12903-019-0792-7

19. Paratelli A, Vania S, Gómez-Polo C, Ortega R, Revilla-León M, Gómez-Polo M.
Techniques to improve the accuracy of complete-arch implant intraoral digital scans: A systematic review. J Prosthet Dent. 2021; 129(6): 844– 854.
doi: org/10.1016/j.prosdent.2021.08.018

20. Passos L, Meiga S, Brigagão V, Street A. Impact of different scanning strategies on the accuracy of two current intraoral scanning systems in complete-arch impressions: an in vitro study. Int J Comput Dent. 2019; 22(4): 307–319.

21. Mizumoto RM, Yilmaz B, McGlumphy EA, Seidt J, Johnston WM. Accuracy of different digital scanning techniques and scan bodies for complete-arch implant-supported prostheses.
J Prosthet Dent. 2020; 123(1): 96–104.
doi: 10.1016/j.prosdent.2019.01.003

22. Imburgia M.
Continuous Scan Strategy (CSS): A novel technique to improve the accuracy of intraoral digital impressions. Eur J Prosthodont Restor Dent. 2020; 28(3): 128. doi: 10.1922/EJPRD_2105Imburgia14

23. Iturrate M, Minguez R, Pradies G, Solaberrieta E.
Obtaining reliable intraoral digital scans for an implant-supported complete-arch prosthesis: A dental technique. J Prosthet Dent. 2019; 121(2): 237–241.
doi: 10.1016/j.prosdent.2018.03.008

24. Ahmed WM, Verhaeghe TV, McCullagh APG.
Maxillary complete-arch implant-supported restoration: A digital scanning and maxillomandibular relationship workflow.
J Prosthet Dent. 2021; 125(2): 216–220.
doi: 10.1016/j.prosdent.2020.01.010

25. Beretta M, Poli PP, Tansella S, Aguzzi M, Meoli A, Maiorana C.
Cast-free digital workflow for implant-supported rehabilitation in a completely edentulous patient: A clinical report.
J Prosthet Dent. 2021; 125(2): 197–203.
doi: 10.1016/j.prosdent.2019.12.009

26. Espona J, Roig E, Ali A, Roig M. Immediately loaded interim complete-arch implant-supported fixed dental prostheses fabricated with a completely digital workflow: A clinical technique. J Prosthet Dent. 2020; 124(4): 423–427.
doi: 10.1016/j.prosdent.2019.08.008

27. Tallarico M, Lumbau A, Scrascia R, Demelas G, Sanseverino F, Amarena R,
et al. Feasibility of using a prosthetic-based impression template to improve the trueness and precision of a complete arch digital impression on four and six implants: an in vitro study. Materials. 2020; 13(16): 3543.
doi: 10.3390/ma13163543

28. Effect of splinting scan bodies on trueness of complete-arch implant impression using different intraoral scanners: an in vitro study. Int J Comput Dent. 2023; 26(1): 19–28.
doi: 10.3290/j.ijcd.b2599297

29. Negreiros WM, Jamjoom FZ, Gallucci G, Hamilton A. Designing a complete-arch digital trial tooth arrangement for completely edentulous patients by using an open-source CAD software program: A dental technique.
J Prosthet Dent. 2021; 125(3): 387–391.
doi; 10.1016/j.prosdent.2020.01.036

30. Fang JH, An X, Jeong SM, Choi BH.
Digital intraoral scanning technique for edentulous jaws. J Prosthet Dent. 2018; 119(5): 733–735. doi: 10.1016/j.prosdent.2017.05.008

31. Peñarrocha-Diago M, Balaguer-Martí JC, Peñarrocha-Oltra D, Balaguer-Martínez JF, Peñarrocha-Diago M, Agustín-Panadero R.
A combined digital and stereophotogrammetric technique for rehabilitation with immediate loading of complete-arch, implant-supported prostheses: A randomized controlled pilot clinical trial. J Prosthet Dent. 2017; 118(5): 596. doi:10.1016/j.prosdent.2016.12.015

32. Revilla-León M, Att W, Özcan M, Rubenstein J.
Comparison of conventional, photogrammetry, and intraoral scanning accuracy of complete-arch implant impression procedures evaluated with a coordinate measuring machine.
J Prosthet Dent. 2021; 125(3): 470–478.
doi: 10.1016/j.prosdent.2020.03.005

33. Sallorenzo A, Gómez-Polo M. Comparative study of the accuracy of an implant intraoral scanner and that of a conventional intraoral scanner for complete-arch fixed dental prostheses.
J Prosthet Dent. 2021; 128 (5): 1009–1016.
doi: 10.1016/j.prosdent.2021.01.032

34. Kim YH, Jung BY, Han SS, Woo CW.
Accuracy evaluation of 3D printed interim prosthesis fabrication using a CBCT scanning based digital model. PLoS One. 2020; 15(10): e0240508. doi: 10.1371/journal.pone.0240508

35. Corominas-Delgado C, Espona J, Lorente-Gascón M, Real-Voltas F, Roig M, Costa-Palau S.
Digital implant impressions by cone-beam computerized tomography: a pilot study. Clin Oral Implants Res. 2016; 27(11): 1407–1413. doi: 10.1111/clr.12754

36. Gómez-Polo M, Ballesteros J, Padilla PP, Pulido PP, Revilla-León M, Ortega R. Merging intraoral scans and CBCT: a novel technique for improving the accuracy of 3D digital models for implant-supported complete-arch fixed dental prostheses.
Int J Comput Dent. 2021; 24(2): 117–123.

37. Mandelli F, Zaetta A, Cucchi A, Mangano FG.
Solid index impression protocol: a hybrid workflow for high accuracy and passive fit of full-arch implant-supported restorations.
Int J Comput Dent. 2020; 23(2): 161–181.

38. Mangano FG, Bonacina M, Mandelli F, Marchiori F.
Solid index versus intraoral scanners in the full-arch implant impression: in vitro trueness evaluation. BMC Res Notes. 2020; 13(1): 504. doi: 10.1186/s13104-020-05353-2

39. Hyspler P, Strnad J, Sala R, Dostalova T.
Reverse scan technique: A verification method for the implant position in intraoral scans. J Prosthet Dent. 2023: S0022-3913(23)00406-7.
doi: 10.1016/j.prosdent.2023.06.008.
Epub ahead of print.

Labels

Maxillofacial surgery Orthodontics Dental medicine

Editorial

Zpráva ze zasedání redakční rady ČSPZL a informace o činnosti časopisu v roce 2024

In memoriam MUDr. Jiří Pekárek

Stomatologická společnost ČLS JEP v roce 2024 – výroční zpráva o činnosti

ENDOGENOUSLY PRODUCED CHEMILUMINESCENCE OF INNER AND OUTER TOOTH STRUCTURES: A PILOT STUDY

Březen patří akcím projektu SDUZ 2025

FDI Young Dentists Forum 2025

Orální medicína – nový vzdělávací obor ve stomatologii

Article was published in

Czech Dental Journal

2025 Issue 1