Print angulation affects fit and efficiency of 3D‑printed aligners—study

The adoption of LCD printing in dentistry is increasing, owing to its high resolution, fast printing times and cost-effectiveness and the growing availability of biocompatible resins validated for LCD. Most research on 3D-printed aligners has looked at stereolithography and digital light processing technologies, however, and few studies have investigated clear resins currently employed in clinical orthodontics.

The researchers examined how print orientation using an LCD system and a clear resin approved for clinical use affects both fit and efficiency. To assess accuracy, the team produced 70 aligners at seven orientations (ten per orientation) and measured dimensional deviations between the aligners and the original digital model.

They found that orienting the aligners parallel to the build platform produced the most accurate aligners, corroborating the findings of another study that found the same for digital light processing and stereolithography printers. They also reported that this orientation required the shortest printing time per build platform, but could accommodate fewer aligners per platform. Steeper angulations showed greater overall deviations and larger height reduction compared with the reference design. Although all the orientations demonstrated some height reduction, discrepancies were generally smaller at lower angles. The authors noted that, although the linear and angular deviations were statistically significant, the absolute differences were clinically negligible.

Aligners printed at 60° starting with the posterior showed the most variable discrepancies, whereas those printed at 60° starting with the anterior were more consistent. This suggests that accuracy is affected also by which part of the arch is being printed and how complex that area is. In contrast, horizontally oriented (0°) aligners likely benefited from more uniform layer stacking and less support-related deformation because this orientation requires the fewest number of layers and the shortest printing time, contributing to improved accuracy and shorter production times.

Clinical relevance and future research

The results indicate that even small changes in print orientation can measurably affect aligner fit and may influence force delivery and treatment predictability. The authors conclude that print angulation should be carefully considered when planning 3D printing of aligners, as it has measurable effects on both accuracy and efficiency—factors that may ultimately affect clinical performance and chairside workflow.

For practices and laboratories incorporating in-house aligner production, the findings identify print orientation as a straightforward optimisation point before investing in new hardware or workflow modifications. While clinical validation is still needed, the results support efforts to standardise orientation as part of quality control.

The study, titled “Effect of print angle on dimensional accuracy and printing efficiency of directly 3D-printed clear aligners”, was published online on 27 January 2026 in Scientific Reports.

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