Abstract
Objectives: This study aimed to evaluate the fitness and retention of presurgical infant orthopedic (PSIO) plates fabricated from three materials—polyethylene terephthalate glycol-modified (PETG), PETG/polyurethane (PETG/TPU), and direct-printed Tera Harz resin—within a standardized in vitro framework. Methods: Thirty molding plates (ten per material) were fabricated on stereolithographic models. Fitness was assessed virtually using Exocad software DentalCAD 3.3 SR1 (exocad GmbH, Darmstadt, Germany), with gap distances measured at 36 standardized points across anterior, middle, and posterior regions. Statistical analysis was performed using Welch’s ANOVA and Games–Howell post hoc comparisons. Retention was tested on soft gum casts using a digital force gauge under simulated intraoral conditions. Plates were seated with denture adhesive, pressurized, and subjected to perpendicular traction until detachment. Mean retentive force was calculated from three repeated trials per plate. Results: PETG plates demonstrated the closest adaptation (0.226 ± 0.060 mm), significantly outperforming direct-printed plates (0.386 ± 0.120 mm; p = 0.006). PETG/TPU plates showed intermediate values (0.321 ± 0.134 mm) without significant deviation from either group. Region-specific analysis revealed the greatest misfit anteriorly, with PETG consistently achieving superior conformity. PETG exhibited the highest mean retentive force (4.30 N), significantly greater than PETG/TPU (2.28 N) and direct-printed plates (0.93 N; p < 0.001). PETG/TPU also performed significantly better than direct-printed plates. Conclusion: Material choice critically influences both the fit and retention of PSIO plates. PETG demonstrated more favorable adaptation and retention under controlled experimental conditions, suggesting potential advantages for appliance stability in presurgical infant orthopedic applications, while PETG/TPU offered moderate performance and direct-printed plates showed the weakest outcomes. Nonetheless, claims of clinical reliability or material superiority cannot be substantiated without further validation. Comprehensive longitudinal clinical studies are therefore required to confirm these preliminary observations and establish their relevance in patient care.