Impact of multi-stacking and resin type on dimensional stability of dentate casts.

Objective To evaluate the effects of multi-stacking and resin type on the dimensional stability of additively manufactured (AM) dentate casts. Methods A master maxillary dentate model file was used to AM casts in a multi-stacked manner, consisting of four layers (L1-L4), using two different resins (DentaMODEL [DM] and KeyModel Ultra Ivory [KM], n = 10). Each cast was digitized one day, one week, two weeks, three weeks, four weeks, and three months after fabrication (T0-T5). The scan files were superimposed over the master file to evaluate the dimensional stability of the casts (anterior, posterior, and entire arch) using the root mean square method. Data were analyzed with a generalized linear model (α = 0.05). Results KM casts had their highest anterior and entire arch deviations when printed at L4 (P < 0.001). DM casts mostly had lower deviations than KM casts across tested layers and storage durations (P < 0.001). DM casts showed the highest anterior deviations at T1 and T2, while KM casts showed the highest at T0, T3, and T4 (P ≤ 0.009). Casts printed at L4 showed the highest anterior deviations at T0 and greater deviations than L1 at T3 and T5, regardless of resin (P ≤ 0.044). KM casts had lower entire arch deviations at T5 than at T3 (P = 0.027). Conclusions While the differences due to stacking were minimal and clinically negligible, the DM casts mostly had higher stability. All casts remained within clinically acceptable limits over three months. Clinical Significance Multi-stacking during printing may be an efficient method for large-scale of plateless dentate casts with clinically acceptable dimensional stability for diagnostic and orthodontic use over three months, when tested resins and three-dimensional printer are used.