From Extraction to Cryobanking: Which Critical Process Parameters Genuinely Improve DPSC Production?

<b>Background</b>: Advanced therapy medicinal products (ATMPs) require strict control of critical process parameters (CPPs) to ensure manufacturing efficiency. The relative impact of donor systemic factors, such as vitamin D status, versus technical process parameters on dental pulp-derived stem cell (DPSC) production remains unclear. <b>Methods</b>: In this prospective observational study, 250 adults undergoing extraction of impacted mandibular third molars were included. Dental pulp was processed under a standardized SOP using different preparation methods and enzyme conditions. Primary endpoints were serum 25(OH)D concentration and cell yield; secondary endpoints included number of passages and cryovials. <b>Results</b>: Mean 25(OH)D concentration was 30.1 ± 14.5 ng/mL and was higher in supplemented individuals (38.2 ± 14.0 vs. 25.6 ± 12.7 ng/mL; <i>p</i> < 0.0001) but was not associated with cell yield (ρ = 0.14, <i>p</i> = 0.168) or passages (ρ = 0.07, <i>p</i> = 0.406). In contrast, process parameters showed strong effects: scissor preparation resulted in a substantially higher yield than mechanical methods (median 5.00 vs. 1.00 million cells; <i>p</i> = 3.6 × 10^-13), and type II collagenase was independently associated with a higher yield (+2.04 million cells; <i>p</i> = 0.026). The number of passages was the strongest predictor of yield (β = 2.28 million per passage; <i>p</i> < 10^-26). Post-thaw viability remained high (mean 90.1% and range 81-98%). <b>Conclusions</b>: Manufacturing efficiency of DPSCs is primarily determined by critical process parameters, particularly preparation method, enzyme selection, and passage control, whereas donor vitamin D status did not significantly influence outcomes under the studied SOP. These findings highlight process standardization as the key driver of reproducible ATMP manufacturing.