Effect of rinsing time on the accuracy of interim crowns fabricated by digital light processing: An in vitro study

Abstract

PURPOSE This study was to evaluate the effect of rinsing time on the accuracy of interim crowns fabricated by digital light processing. MATERIALS AND METHODS The maxillary right first molar master die was duplicated using a silicone material, while a study die was produced using epoxy resin. Scans of the epoxy resin die were used in combination with CAD software to design a maxillary right first molar interim crown. Based on this design, 24 interim crowns were fabricated with digital light processing. This study examined the trueness and precision of products that were processed with one of the three different postprocessing rinsing times (1 min, 5 min, and 10 min). Trueness was measured by superimposing reference data with scanned data from external, intaglio, and marginal surfaces. Precision was measured by superimposing the scan data within the group. The trueness and precision data were analyzed using Kruskal-Wallis, nonparametric, and post-hoc tests, and were compared using a Mann-Whitney U test with Bonferroni correction (α=.05). RESULTS The trueness of the external and intaglio surfaces of crowns varied significantly among the different rinsing times ( P =.004, P =.003), but there was no statistically significant difference in terms of trueness measurements of the marginal surfaces ( P =.605). In terms of precision, statistically significant differences were found among the external, intaglio, and marginal surfaces ( P =.001). CONCLUSION Interim crowns rinsed for 10 minutes showed high accuracy.

Comparison of Intaglio Surface Trueness of Interim Dental Crowns Fabricated with SLA 3D Printing, DLP 3D Printing, and Milling Technologies

“…The fabricated interim crowns were washed to remove all residual resin following the manufacturer's recommendations. After interim crowns were fabricated, each interim crown was rinsed with 95% isopropyl alcohol for 5 min using an ultrasonic cleaner, followed by post-polymerization using a curing unit (CUREDEN; Kwang Myung DAICOM, Seoul, Korea) for 15 min [28]. A desktop scanner (E1, 3Shape, Copenhagen, Denmark) was used to scan the fabricated interim crowns under high-precision scan mode by designating the intaglio surface using, and the scanned virtual crowns were designated as CTMs (Figure 1).…”

“…In the dental CAD/CAM system, CAM can be largely divided into milling and additive technologies, and 3D printing, an additive technology, is widely used for manufacture of dental interim prosthesis [25][26][27][28]. Srinivasan et al [29] and Kalberer et al [30] evaluated the 3D trueness to verify the volume change of the intaglio surface of the fabricated dental prosthesis.…”

“…Various 3D printer technologies are being applied for the fabrication of dental prostheses [25][26][27][28]. In the fabrication of dental prostheses using 3D printing with photosensitive resin, stereolithography apparatus (SLA), and digital light processing (DLP) technologies are popularly used [25][26][27][28]. The DLP 3D printer is a technology that uses a light projector to project an image to polymerize photosensitive resin [28].…”

“…In the fabrication of dental prostheses using 3D printing with photosensitive resin, stereolithography apparatus (SLA), and digital light processing (DLP) technologies are popularly used [25][26][27][28]. The DLP 3D printer is a technology that uses a light projector to project an image to polymerize photosensitive resin [28]. The SLA 3D printer is a technology that performs layer-by-layer polymerization using ultraviolet laser to polymerize photosensitive resin [27].…”

“…The SLA 3D printer is a technology that performs layer-by-layer polymerization using ultraviolet laser to polymerize photosensitive resin [27]. Previous studies evaluated the trueness of dental prostheses using SLA and DLP techniques [25][26][27][28], but studies evaluating both SLA and DLP technologies are still lacking. Also, studies evaluating trueness according to specific areas of intaglio surface of interim crowns are still lacking, except for the present study.…”