Comparison of water absorption of 3D printing resins and conventional composite resins

Aim: This study aimed to compare the water sorption of a nanohybrid composite resin and two 3D-printed resin materials over varying storage periods. Materials and methods: A total of 60 cylindrical specimens (8.0 mm diameter and 2.0 mm thickness) were prepared and divided into three groups (n=20) based on the materials used: a nanohybrid composite (Kuraray Clearfil Majesty Esthetic, NC, Japan) and two 3D-printed resin materials (Saremco Crowntec, SC, Switzerland; VarseoSmile Crown Plus, VS, Germany). NC specimens were fabricated using stainless steel molds, while SC and VS specimens were prepared using a Phrozen Sonic Mini 8K MSLA 3D printer (Phrozen Technology, Taiwan). Post-processing for SC and VS included immersion in ethanol for 5 minutes and UV curing at 405 nm for 20 minutes. All specimens were stored in a desiccator until a constant mass was achieved and then immersed in distilled water. Water sorption (WS) was evaluated according to ISO 4049:2009 standards at 1, 7, 30, and 90 days. Statistical analysis was performed using one-way ANOVA and Tukey's post-hoc test at a significance level of p<0.05. Results: The nanohybrid composite (NC) exhibited significantly higher water sorption values at all time points compared to the 3D-printed groups (SC and VS) (p<0,05). Between the 3D-printed resins, SC showed significantly higher water sorption than VS at 1 and 7 days(p<0,05) however, no significant difference was observed at 30 and 90 days(p>0,05). All materials demonstrated a rapid increase in water sorption in the first week, followed by a slower rate of absorption as storage time progressed. Conclusions: The nanohybrid composite (NC) exhibited greater water sorption compared to the 3D-printed resin materials. These findings suggest that 3D-printed resin materials, may be a suitable alternative for long-term clinical restorations. Keywords: Water sorption, Nanohybrid composite, 3D-printed permanent crown material, Dental materials.