Effect of surface treatment protocols on the maintenance of a light-activated characterization coating for 3D printable composite resin.

STATEMENT OF PROBLEM

Effective methods for improving the maintenance of light-activated characterization coatings for 3-dimensionally (3D) printable composite resin need to be investigated, and an appropriate working protocol must be established.

PURPOSE

The purpose of this in vitro study was to determine the effect of treatment protocols on the maintenance of characterization coating in 3D printed dental restorations by focusing on preserving color stability and gloss retention to support clinical longevity.

MATERIAL AND METHODS

Fifty disk-shaped (Ø12×2 mm) specimens were prepared with a 3D printable composite resin and divided into 10 groups (n=5) according to the surface treatment (aluminum oxide airborne-particle abrasion, phosphoric acid, silane, or adhesive). They were coated with a light-activated characterization and a sealant. Color stability, surface roughness, and gloss tests were conducted before and after a toothbrushing abrasion simulation (20 000 cycles). Color change (ΔE00, based on the CIE2000 standard) was measured using a spectrophotometer, surface roughness (Ra) with a profilometer, and gloss (GU) with a glossmeter. Two-way repeated measures analyses of variance (ANOVA) followed by Tukey post hoc tests (α=.05) were used to analyze the results for roughness and gloss before and after toothbrush abrasion. One-way ANOVA followed by the Tukey post hoc test was used for color difference.

RESULTS

Before the brushing simulation, the group that used the complete surface treatment protocol exhibited the lowest Ra values. After brushing, no statistically significant differences were observed (P>.05). Groups to which adhesive had not been applied and those treated exclusively with characterization and sealant exhibited the highest gloss values before the simulation. However, no difference in gloss values was found among the groups after brushing, except for the control group, which showed the lowest values. High color changes were observed in groups where adhesive or silane was applied separately without abrasion beforehand.

CONCLUSIONS

Overall, the surface treatments applied resulted in lower roughness and higher gloss. However, they led to treatments with reduced color stability compared with those without the characterization agent.