Jee-Hwan Kim

Asaka K, et al. J Korean Acad Prosthodont. 2026 Oct;64(4):341-350. https://doi.org/10.4047/jkap.2026.64.4.341

Liu Y, et al. J Adv Prosthodont. 2026 Oct;18(5):410-419. https://doi.org/10.4047/jap.2026.18.5.410

Han WG, et al. J Adv Prosthodont. 2026 Aug;18(4):347-361. https://doi.org/10.4047/jap.2026.18.4.347

Denture base resins are susceptible to microbial colonization, and current antibacterial additives often lose effectiveness and may weaken material properties. This study evaluated whether immersion in a quaternary ammonium methacryloxy silane (QAMS)-containing monomer can enhance antibacterial activity without compromising the mechanical properties of digital light processing–printed urethane dimethacrylate denture base resin. Specimens of printed denture base resin were immersed in mixtures of denture base resin and a QAMS-containing monomer at ratios of 10:0 (Control), 7:3 (K3), 5:5 (K5), 3:7 (K7), and 0:10 (K10), followed by post-curing. Flexural strength and modulus were measured by three-point bending, and surface hardness was assessed by Vickers microhardness testing. Antibacterial activity against Streptococcus mutans was assessed by inhibition-zone and colony-counting assays. All QAMS-treated groups preserved flexural strength, with a slight reduction in modulus in K5 (p < 0.05), while hardness remained unchanged. Antibacterial activity improved in all QAMS-treated groups; K5 and K7 showed the strongest results. Surface analyses using scanning electron microscopy and energy-dispersive X-ray spectroscopy verified formation of a Si-rich modified layer. QAMS immersion followed by post-curing produced a stable, contact-active antibacterial surface without reducing mechanical properties. Among the formulations, K7 (~21 wt% QAMS) provided the most favorable balance of antibacterial activity and mechanical performance.

Given the growth-related challenges in pediatric and adolescent patients and the increasing adoption of digital workflows, durable yet adaptable materials are needed for provisional restorations. This study evaluated the mechanical performance of two 3D-printed resins, Graphy TC-80DP (GP) and NextDent C&B MFH (ND), and a milled nano-hybrid resin, Mazic Duro (MD). A multidimensional assessment was conducted, including fracture resistance, flexural strength, flexural modulus, viscoelasticity, and polymerization behavior. ND showed the highest fracture resistance, MD exhibited superior flexural strength and flexural modulus, and GP demonstrated faster polymerization and greater thermal stability. These findings suggest that both 3D-printed and milled resins are clinically viable for pediatric provisional restorations, with material selection depending on occlusal load, patient age, and functional demands.

This study investigated the effect of vacuum plasma treatment on the shear bond strength (SBS) of three-dimensional (3D)-printed resin and resin cement. Specimens were categorized based on airborne-particle abrasion (APA), plasma, and bonding agent treatments. Long-term adhesive stability was examined by comparing their SBSs before and after thermocycling. The group with the bonding agent applied after plasma treatment and before thermocycling exhibited the highest SBS of 23.9±2.2 MPa. No significant SBS difference was observed among the remaining groups, except for that subjected only to plasma treatment after thermocycling. The wettability of distilled water improved in the groups treated with plasma, whereas that of the bonding agent decreased in the group treated only with APA. Surface analysis revealed a roughened surface on the plasma-treated 3D-printed resin. Therefore, vacuum-plasma treatment before thermocycling can enhance the SBS of 3D-printed resin without compromising its properties.