Does ecologically sustainable printing and postprocessing enable dimensionally stable dental casts?

Objective To assess how resin type (water-washable [WW] and non-water-washable [NWW] and cleaning solution (water, methyl ether solvent [MES], or isopropyl alcohol [IPA]) affect the dimensional stability of additively manufactured casts over a three-month period. Methods Maxillary casts were fabricated using two WW (WW1 and WW2) and one NWW (NWW) cast resins (N = 24). These casts were divided into groups depending on the cleaning solution (water, MES, and IPA) used (n = 8), and digitized one day (T0), one week (T1), two weeks (T2), three weeks (T3), and three months (T4) after fabrication. Deviations were analyzed across regions (anterior, posterior, entire arch, soft tissue, and overall). A generalized linear model was used for statistical analysis (α = 0.05). Results NWW casts had the lowest anterior, posterior, and entire arch deviations (P < 0.001). WW1 casts mostly showed higher deviations than WW2 casts in these regions when cleaned with water or MES (P ≤ 0.028). WW1 casts had the highest soft tissue deviations within each cleaning solution (P < 0.001). With water, WW1 casts had higher deviations than with MES, while WW2 casts showed lower deviations than NWW casts (P ≤ 0.032). NWW resin or MES led to the lowest entire cast deviations, with the lowest values observed at T0 (P ≤ 0.007). Conclusions NWW casts mostly had the highest stability, while WW2 casts mostly had higher stability than WW1 casts. MES led to higher stability for WW resins and resulted in similar or higher stability for NWW resin compared to IPA. Clinical Significance Tested water-washable resins, particularly when cleaned with methyl ether solvent, may be sustainable alternatives to non-water-washable resin for dentate casts, as their deviations were acceptable for diagnostic and orthodontic purposes for three months. Methyl ether solvent can improve eco-friendliness of the fabrication of casts in tested non-water-washable resin.