Suppress warpage in support-free DLP orthodontic molds: A hybrid strategy combining honeycomb structures and process-parameter screening.

Warpage deformation caused by nonuniform shrinkage stress represents a critical barrier to the clinical application of orthodontic dental molds fabricated via Digital Light Processing (DLP). To address this issue, this study proposes an active suppression strategy based on embedded honeycomb microstructures and systematically investigates the deformation regulation of dental molds during DLP processing through a synergistic combination of process optimization and structural design. Moderate temperature (35 °C) and light intensity (2.5 mW cm-2) are conducive to reducing resin viscosity, improving leveling performance, and optimizing light transmittance and curing uniformity, thereby mitigating the internal stress induced by temperature gradients and nonuniform light absorption. The honeycomb structure dissipates and absorbs shrinkage stress through geometric deformation, resulting in a remarkable reduction in overall warpage. With optimized process parameters, the honeycomb-embedded dental mold achieved high-accuracy, support-free forming. This study provides guidance for overcoming the large-scale production bottleneck of support-free, high-accuracy orthodontic dental molds.