[The effect of autoclaving conditions on the microstructure of the Dental Yellow Clear PRO photopolymer material produced by stereolithography].

OBJECTIVE

A comparative study of the effect of two clinically acceptable steam sterilization modes on the microstructure of samples made of the domestic photopolymer material Dental Yellow Clear PRO using stereolithography with different layer heights.

MATERIAL AND

METHODS

Disc-shaped specimens were printed with layer height of 0.05 mm and 0.1 mm and subsequently sterilized using two autoclaving protocols: a "Soft Program" (121°C, 1.1 bar, 15 min) and a "Flash Program S" (134°C, 2.2 bar, 3.5 min). Surface morphology and interlayer integrity were analyzed using field-emission scanning electron microscopy (FE-SEM).

RESULTS

Autoclaving did not lead to interlayer delamination or macroscopic structural defects, regardless of layer thickness. Sterilization at 121°C resulted in partial smoothing of interlayer boundaries without signs of substantial material degradation. In contrast, sterilization at 134°C produced more pronounced alterations, including localized surface softening and the formation of microstructural heterogeneities, whose distribution and characteristics may be related to degassing of low-molecular-weight components in the polymer matrix.

CONCLUSION

The two sterilization regimes exerted different levels of thermal impact on the surface microstructure of the photopolymer while maintaining overall structural integrity. The 121°C protocol is recommended as a gentler method for preserving the original morphology of SLA-printed Dental Yellow Clear PRO specimens.