BMC Oral Health. 2026 Jul 20. doi: 10.1186/s12903-026-09183-9. Online ahead of print.
ABSTRACT
BACKGROUND: Additive manufacturing has expanded the clinical application of resin-based materials for definitive fixed dental prostheses (FDPs). This study aimed to evaluate the effect of different printing orientations on marginal and internal misfit, overall discrepancy, and fracture load of three-unit FDPs fabricated from a reinforced resin-based material (VarseoSmile TriniQ).
METHODS: Forty-eight three-unit FDPs were fabricated and divided into four groups (n = 12): a lithium disilicate control group (IPS, IPS e.max CAD) and three experimental groups of a permanent composite resin (VST, VarseoSmile TriniQ) printed at 0°, 45°, and 90° build orientations (VST-0, VST-45, and VST-90). Marginal and internal misfit values were evaluated using micro-computed tomography (micro-CT) before and after chewing simulation. Dynamic aging was followed by fracture load testing using a single-load-to-failure protocol. Failure modes were classified under stereomicroscopic examination. Data were analyzed using nonparametric statistical methods. Intergroup comparisons were performed using the Kruskal-Wallis test with Dunn’s post hoc analysis, while pre- and post-aging comparisons were assessed using the Wilcoxon signed-rank test. Correlations between misfit parameters and fracture load were evaluated using Spearman’s rank correlation analysis (α = 0.05).
RESULTS: Printing orientation significantly affected the marginal and internal misfit of TriniQ restorations. The 45° build orientation demonstrated the most consistent fit values both before and after the chewing simulation. Chewing simulation resulted in statistically significant increases in marginal, internal misfit as well as overall discrepancy values across all groups (p < 0.05). No statistically significant differences in fracture load were observed among the groups (p = 0.094). However, the IPS control group exhibited the highest Weibull modulus (m = 8.41). Spearman’s rank correlation analysis revealed no statistically significant correlations between fracture load and overall discrepancy in any group (p > 0.05). IPS restorations predominantly exhibited catastrophic brittle fractures, whereas TriniQ restorations mainly exhibited connector-related and deformation type failure patterns.
CONCLUSIONS: Build orientation influenced the adaptation accuracy of additively manufactured three unit FDPs, whereas no statistically significant differences in fracture load were observed among the groups. Minor variations in overall discrepancy did not appear to influence fracture load under static loading conditions. All tested groups exhibited fracture resistance values exceeding reported physiological masticatory forces. IPS e.max CAD restorations demonstrated higher structural reliability and more consistent, yet comparatively brittle, fracture behavior.
PMID:42477658 | DOI:10.1186/s12903-026-09183-9
