In Vitro Evaluation of the Post-Space Depth Reading With an Intraoral Scanner (Ios) Compared to a Traditional Silicon Impression

Abstract

SUMMARYObjectives. The aim of the study was to assess the depth and quality of the post-space reading, using an IOS without scanpost, compared to a traditional silicon technique. Methods. Six extracted bicuspids were decoronated and endodontically treated. After having prepared the space for the posts, a structure in pink acrylic resin was created with two resin elements. At the center of the structure one sample was put at a time. Digital and traditional impressions were taken for each sample. Digital impressions were developed through the Computer-aided design (CAD) software in order to integrate the scanner results into a three-dimensional grid to make the measurements. A K-file was used to measure the length of the postspace of each sample obtained through the traditional silicon impression and subsequently the measurement results were reported on a millimeter gauge. Furthermore, an assessment of the width of the entrances of the post-spaces was carried out. Results. The mean reading depth discrepancy expressed in percentages (19.58%) indicates that the digital impression with current technologies fails to impress clearly the post-space. Standard deviation of the data expressed in percentage is 13.89, suggesting that the values were not similar to each other. In two cases the digital technique has achieved less than 10% difference compared to the traditional technique, but there have been also cases in which the variation in depth has reached almost 40%. The samples that showed the minor discrepancy between the two techniques expressed the widest post-space entrance. Conclusions. In this in vitro study, the application of the IOS for the post-space reading in order to deliver an anatomic post has been proven to be still not reliable, as there are still depth reading limitations for the narrow root channels. In fact, in this type of channels it is difficult to reach with the light beam of the IOS the deepest areas of the post-space, with a consequent incomplete post-space reading.

Influence of Implant Scanbody Wear on the Accuracy of Digital Impression for Complete-Arch: A Randomized In Vitro Trial

“…IOS was suggested to be a reliable alternative in the clinical practice to conventional impression methods in the manufacture of implant-supported crowns and short-span fixed dental prostheses [ 22 ]. Moreover, digital implant impressions could offer advantages over conventional impressions, such as reduced risks of distortion during the impression and laboratory phases, improved patient comfort and acceptance, and improved time efficiency [ 23 , 24 ]. However, digital workflow is still subject to errors, which could derive from the digital impression and CAD/CAM software, as well as production (subtractive or additive) manufacturing processes.…”

Accuracy of Digital Impression Taking with Intraoral Scanners and Fabrication of CAD/CAM Posts and Cores in a Fully Digital Workflow

“…An in vitro study by Pinto et al [18] compared digital and conventional impression techniques for CAD/CAM-P+C with regard to impression depth. The investigated area was compared to the apical measurement area in the present study.…”

“…There are two possible sources of error during the manufacturing of CAD/CAM-P+C: inaccuracies within intraoral scanning of prepared root canals [18], and manufacturingrelated inaccuracies due to CAD/CAM milling [17,19].…”

“…To date, there is only one study in the literature that compared the depth of digital impressions and conventional silicon impressions for P+C [18]. There are also few studies on the accuracy of fit of P+C fabricated by taking impressions using IOS with or without SP [5,17,19].…”

Effect of freshly placed core buildup composites on setting of silicon impression materials

“…[ 4 5 ] Some studies have shown that intraoral scanners are less accurate when capturing details of full arch reconstructions or postpreparations. [ 6 7 ] Scanners also are less suited for capturing subgingival details when preparations of teeth are cervical to the gingival margin. [ 8 ]…”