Dimensional stability of 3D-printed models for orthodontic aligners: a six-month storage evaluation

Objective: This study aimed to analyze the dimensional stability of 3D resin-printed models for orthodontic aligners under specific storage conditions over a period of up to six months. Methods: A model of the upper arch of a dental mannequin (Orbital Bone) was scanned using the 3Shape Trios 3 scanner, to create digital models (n = 20), which were printed on the Anycubic Photon X6 KS printer and stored in a dark box at room temperature for six months. Dimensional analysis was performed by comparing the meshes of the models through superimposition at the following time points: T0 - immediately after printing (control group), T1 - 1 month, T2 - 3 months, and T3 - 6 months of storage. The Ortho Analyser software was used for this purpose, and measurements were performed by a single, trained examiner. After confirming normality (p > 0.05, Shapiro-Wilk test), Analysis of Variance (ANOVA) was applied to verify dimensional changes in the following regions of the dental arch: incisors, canines, premolars, and molars. Results: Dimensional changes in the models were not statistically significant (p > 0.05) during the storage period for all evaluated regions. However, the greatest dimensional changes occurred during the first month and in the molar region (0.175 mm), which showed a tendency to expand. Conclusions: After six months of storage in a light-free environment, the 3D-printed models exhibited minor dimensional changes, which may have some clinical impact on aligner treatment, particularly in the molar region.