Clinical planning of all-ceramic crown restorations based on intraoral digital impressions

Digital prints are becoming increasingly popular as digital technologies can provide a faster, more convenient and cheaper workflow.

The aim is to propose the design of prosthetics with ceramic prosthetic structures made on the basis of intraoral digital casts.

Object and methods. Intraoral scanning was performed in 52 patients, whose average age was 34.62±2.74 years. The patients were trained in intraoral scanning, crown design using CAD software, and all digital workflows, including the CAM process. Сканирование полным сканером Medite i500 (Медиа-корпорация, Сеул, Корея). Statistical data processing was carried out using the Microsoft Excel 2016 program. Descriptive statistics are used.

Results. Restorations were checked for marginal and interproximal fit. All of them are fitted precisely, without any backlashes and gaps. The order of placement of restorations has been determined. To build the correct anatomical contour for all-ceramic crowns, J-shaped and knife edges are not suitable. Both shoulders and chamfers are preferred. When creating a contact point, a virtual model with a restoration proposal was viewed from an occlusal point of view; it was determined whether the buccal-palatine contour was convex; the virtual model was viewed from the buccal side and determined whether the gingival-occlusal contour was convex; it was viewed from the mesial side; the virtual model was installed at an angle of 45 ° and the area was stretched until it was The desired size was reached and the surface did not become convex; the final polishing was performed by rotating the proposed restoration and virtual model.

Conclusion. The main components of the clinical design of prosthetics with all-ceramic crowns made using intraoral digital casts are: cavity preparation/design of dental preparation; interarticular stability; ultimate integrity; occlusal stability; accuracy of the digital impression. Digital design creates the opportunity to make treatment simpler and more accurate.

1. Zitzmann N.U., Kovaltschuk I., Lenherr Pэ, Dedem P., Joda T. Dental Students' Perceptions of Digital and Conventional Impression Techniques: A Randomized Controlled Trial. J Dent Educ. 2017;81(10):1227-1232. https://doi.org/10.21815/JDE.017.081

2. Bandiaky O.N., Le Bars P., Gaudin A., Hardouin J.B., Cheraud-Carpentier M., Mbodj E.B., Soueidan A. Comparative assessment of completecoverage, fixed tooth-supported prostheses fabricated from digital scans or conventional impressions: A systematic review and metaanalysis. J Prosthet Dent. 2022;127(1):71-79. https://doi.org/10.1016/j.prosdent.2020.09.017

3. Pradíes G., Zarauz C., Valverde A., Ferreiroa A., Martínez-Rus F. Clinical evaluation comparing the fit of all-ceramic crowns obtained from silicone and digital intraoral impressions based on wavefront sampling technology. J Dent. 2015;43(2):201-8. https://doi.org/10.1016/j.jdent.2014.12.007

4. Alwadai G.S., Al Moaleem M.M., Daghrery A.A., Albar N.H., Daghriri A.A. et al. A Comparative Analysis of Marginal Adaptation Values between Lithium Disilicate Glass Ceramics and Zirconia-Reinforced Lithium Silicate Endocrowns: A Systematic Review of In Vitro Studies. Med Sci Monit. 2023;29:e942649. https://doi.org/10.12659/MSM.942649

5. Oh W.S. Cement Type (Adhesive vs. Conventional) May Not Affect Clinical Performance of Zirconia and Lithium Disilicate Tooth-Supported Crowns. J Evid Based Dent Pract. 2020;20(2):101415. https://doi.org/10.1016/j.jebdp.2020.101415

6. Spehar D., Jakovac M. Clinical Evaluation of Reduced-Thickness Monolithic Lithium-Disilicate Crowns: One-Year Follow-Up Results. Processes. 2021;9(12):2119. https://doi.org/10.3390/pr9122119

7. Marchesi G., Camurri Piloni A., Nicolin V., Turco G., Di Lenarda R. Chairside CAD/CAM Materials: Current Trends of Clinical Uses. Biology (Basel). 2021;10(11):1170. https://doi.org/10.3390/biology10111170

8. Cokic S.M., Vleugels J., Van Meerbeek B., Camargo B., Willems E., Li M., Zhang F. Mechanical properties, aging stability and translucency of speed-sintered zirconia for chairside restorations. Dent Mater. 2020;36(7):959-972. https://doi.org/10.1016/j.dental.2020.04.026

9. Rosentritt M., Schmid A., Huber C., Strasser T. In Vitro Mastication Simulation and Wear Test of Virgilite and Advanced Lithium Disilicate Ceramics. Int J Prosthodont. 2022;35(6):770–776. https://doi.org/10.11607/ijp.7820

10. Ender A., Zimmermann M., Mehl A. Accuracy of complete- and partial-arch impressions of actual intraoral scanning systems in vitro. Int J Comput Dent. 2019;22(1):11-19.