Effect of dental dam color on intraoral scanning deviations during cut-out and rescan procedure: a clinical evaluation

Background The cut-out and rescan procedure is commonly used in restorative digital workflows to update localized areas after clinical procedures. However, clinical evidence on scanning deviations associated with this workflow under dental dam isolation remains limited. This study evaluated scanning deviations during the cut-out and rescan procedure and assessed the effects of dental dam color and intraoral scanner system. Methods Initial scans/prescan data of the mandibular right posterior quadrant were obtained from 20 patients by using two intraoral scanners (CEREC Primescan and iTero Element 5D). Light blue and black dental dam isolation was applied sequentially. The second premolar region (including approximately 1 mm of adjacent teeth) was cut out from the prescan dataset and rescanned over the dental dam. The software of both scanners automatically overlapped the rescan with the prescan and filled the cut-out area. Prescan and rescan standard tessellation language (STL) datasets were imported into Geomagic Control X (3D Systems) and superimposed using registration and best-fit tools. Scanning deviation was defined as the prescan-referenced root mean square (RMS) deviation (µm) between prescan and rescan datasets for the second premolar. Data were analyzed using generalized estimating equations (GEE), with patient ID included in the model to account for repeated measurements (α = 0.05). Results RMS was 72.05 ± 39.38 μm for Element 5D and 61.80 ± 30.52 μm for Primescan, with no significant difference ( P = 0.066). Dental dam color did not affect RMS (light blue: 69.28 ± 37.65 μm; black: 64.58 ± 33.28 μm; P = 0.120), and the scanner×color interaction was not significant ( P = 0.062). Conclusions The cut-out and rescan procedure under dental dam isolation produced limited prescan-referenced deviations for both scanners. These deviations were not significantly affected by scanner type or dental dam color, indicating similar prescan-referenced RMS deviations for localized rescanning with light blue and black dental dams under the tested conditions. Trial registration ClinicalTrials.gov, NCT06893263. Registered 25 March 2025.