Impact of varnishing, coating, and polishing on the chemical and mechanical properties of a 3D printed resin and two veneering composite resins.

STATEMENT OF PROBLEM

Three-dimensional (3D) printing enables the fast fabrication of definitive fixed dental prostheses (FDPs). However, data on the effects of surface treatments on their chemical and mechanical properties are lacking.

PURPOSE

The purpose of this in vitro study was to examine the influence of different surface treatments on a 3D printed resin in comparison with 2 veneering composite resins.

MATERIAL AND METHODS

A total of 288 specimens were manufactured from a 3D printed resin (VarseoSmile Crown) or veneering composite resins (GRADIA PLUS; VITA VM LC flow). Surfaces underwent varnishing, coating, polishing or remain untreated. Conversion rate (DC), surface roughness (SR), Martens parameter, flexural strength (FS), and 3-body wear (3BW) were determined (n=12). Statistical analysis was performed using Mann-Whitney-U, Kruskal-Wallis, and Spearman correlation tests (α=.05).

RESULTS

After polishing, the 3D printed resin showed higher DC, SR, and 3BW but lower Martens parameters compared with veneering composite resins (P<.007). After goat hair brushing, the 3D printed resin showed lower FS than VITA-VCR (P=.043). For the 3D printed resin, goat hair brushing or GC-Varnish reduced SR, while VITA-Varnish showed the lowest 3BW (P<.045). For both veneering composite resins, goat hair brushing led to low SR and 3BW and high E and FS (P<.043). Silicone polishing led to low E of the 3D printed resin and low E and FS of GC-VCR (P<.009). Coating resulted in a lower E than the untreated surface and higher 3BW than GC-Varnish (P<.030).

CONCLUSIONS

The 3D printed resin showed higher DC, SR, 3BW and lower HM, E, and FS values than the veneering composite resins. Polishing with a goat hair brush can be recommended for all tested materials. For the 3D printed resin, varnishing presents a promising alternative with regard to SR and 3BW. Silicone polishing and coating cannot be recommended.