Comparison of tissue surface adaptation of maxillary denture bases fabricated using conventional and digital impression techniques

TEKDEMİR Ş.S., Comparison of Tissue Surface Adaptation of Maxillary Denture Bases Fabricated Using Conventional and Digital Impression Techniques. Hacettepe University, Faculty of Dentistry, Thesis in Prosthodontics, Ankara, 2023. There are limited studies on the accuracy of digital impressions in edentulous jaws. The aim of this clinical study was to evaluate the tissue adaptation of denture bases fabricated using conventional and digital impressions in maxillary edentulous patients. Three impression techniques were used: G; conventional impression method, DI; intraoral scanner with triangulation system (Medit i600, Medit Corp, Seoul, Korea), DII; intraoral scanner with confocal system (Trios 4, 3Shape, Copenhagen, Denmark) (n=15). Denture bases were produced using 3D printing technology. Reference data were created by scanning the intaglio surface of the bases with a laboratory scanner. In order to evaluate the tissue adaptation, a light-body polyvinylsiloxane impression material was applied on the tissue surface of the denture base and placed in the patient's mouth. Polymerization of the material was completed under a constant pressure of 20 N with the help of a specially designed apparatus. The intaglio surfaces of the denture bases were once again scanned with a laboratory scanner. The intaglio surface scans were superimposed using a best-fit program (GOM Inspect Professional 2017, Braunschweig Germany). Quantitative measurements were made at three different regions. Friedman non-parametric statistical analysis test was used to evaluate the results. There was no difference between the methods in overall intaglio area (p>0.05). DII had the lowest deviation in the palate area, while a significant difference was found with G (p<0.01). The lowest deviation in the vestibular sulcus were detected in G, while a significant difference was found between both DI and DII methods (p<0.001). In the impression of edentulous patients, the digital method showed similar results to the conventional method. However, the impression regions showed higher deviation compared to the conventional impression, especially in the peripheral border areas. Keywords: Complete denture, intraoral scanner, digital impression, base, adaptation Supported by: H.Ü.B.A.P.K.B. Support Project (Project Code: THD-2023-20664)