Objective <p>Three-dimensional (3D) printing technologies are increasingly used in the fabrication of space maintainers in pediatric dentistry. However, studies on improving the properties of space maintainer materials produced by digital methods remain limited. The aim of this study was to evaluate the potential of a 3D printing resin modified with glass ionomer cement powders as a new-generation composite space maintainer material for pediatric dentistry in terms of mechanical properties. This study addresses the question of whether a 3D printing resin modified with glass ionomer cement powders can serve as a new-generation space maintainer material with favorable mechanical properties.</p> Materials and methods <p>Two different glass ionomer cement powders as fluoride sources were added to a 3D printing resin at different concentrations, and four experimental groups were formed. Unmodified resin was used as the control group, while acrylic was used as the clinical reference group. Mechanical properties of the composite space maintainers were assessed using three-point bending and tensile tests.</p> Results <p>Groups with lower filler levels generally exhibited a more balanced mechanical performance. In the tensile analysis, filler type had a significant effect on maximum stress (<i>p</i> = 0.0135), while filler level had a significant effect on maximum stress (<i>p</i> &lt; 0.0001), maximum strain (<i>p</i> = 0.0191), and elastic modulus (<i>p</i> &lt; 0.0001). Low-level filler groups showed mechanical behavior closer to that of the acrylic reference material.</p> Conclusion <p>The addition of glass ionomer powder altered the mechanical behavior depending on the filler ratio. Low filler levels provided better preservation of mechanical properties. Although these materials show potential as new-generation space maintainers in pediatric dentistry, further in vitro and in vivo studies are required to confirm their clinical applicability.</p>