Effect of finishing and polishing and aging protocols on the mechanical properties, surface characteristics, and Candida albicans adherence of 3-dimensional-printed and prefabricated dental resins for definitive restorations.

BACKGROUND

The authors aimed to evaluate the effects of different finishing and polishing (FP) protocols and aging (thermocycling [TC]) on the flexural strength, microhardness, surface roughness, and Candida albicans adherence of 3-dimensional (3D)-printed and prefabricated resins for definitive restorations.

METHODS

A total of 360 specimens (240 from 3D-printed resins and 120 from Tetric CAD [T] resin, Ivoclar Vivadent) were fabricated and divided into 24 groups (n = 15) on the basis of resin, FP protocol (ie, control, diamond bur, composite resin rubber, and a combination of diamond bur and composite resin rubber), and aging (with, without). The specimens were stored (37 °C for 24 hours) or thermocycled for 10,000 cycles. Specimens were tested for flexural strength (in megapascals), Vickers microhardness (in gigapascals), surface roughness (arithmetical mean height in micrometers), C albicans adhesion (logarithm of colony-forming units per milliliter), and scanning electron microscopy. Statistical analyses included analysis of variance, Tukey test, Weibull analysis, and Kruskal-Wallis test.

RESULTS

The T resin exhibited higher flexural strength values than the 3D-printed resins (P < .01). The T resin and diamond bur FP group had the highest arithmetic mean height among all groups (P < .01). Lower microhardness values were observed for the T resin and composite resin rubber FP with aging (TC) group and the T resin and diamond bur FP with aging (TC) group than the groups without aging (P < .01). C albicans adherence was not influenced by means of the resin and FP factors.

CONCLUSIONS

Rubber polishing maintained mechanical strength and produced the smoothest surfaces in both printed and prefabricated resins but did not influence C albicans adhesion. Aging affected the prefabricated resin only, reducing its strength and microhardness.

PRACTICAL IMPLICATIONS: Rubber polishers are recommended for FP printed or prefabricated resin materials and diamond burs should be avoided. However, if diamond burs must be used, subsequent polishing with rubber polishers can help mitigate any adverse effects.