Effect of immersion in disinfectants on the color stability of denture base resins and artificial teeth obtained by 3D printing.

PURPOSE: To evaluate the effect of immersion in disinfecting solutions on the color stability of denture base resins and artificial teeth obtained by 3D printing. MATERIALS AND METHODS: Forty discs (15 × 3 mm) were obtained for each group: Lucitone 550 and Cosmos Denture 3D (denture base resins), Duralay and Cosmos TEMP 3D (artificial teeth resins). The discs were immersed in disinfectant solutions: Corega Tabs, 2% chlorhexidine digluconate, 0.25% sodium hypochlorite, and distilled water. Color measurements were obtained with a spectrophotometer before immersion in disinfectants and after the simulated periods of 6 and 12 months. Data (ΔE00 ) were submitted to mixed three-way ANOVA and Bonferroni post-test. RESULTS: For denture base resins, Cosmos Denture 3D showed greater color change regardless of the solution and immersion time. The immersion time of 6 months influenced the color change of the denture base resins regardless of the disinfectant solution. For the artificial teeth resins, the immersion time of 12 months showed a significant color change when compared to 6 months. Cosmos TEMP 3D showed greater color change for all solutions, except for 0.25% sodium hypochlorite. Duralay resin showed greater color change in 2% chlorhexidine, regardless of immersion time. CONCLUSIONS: For denture base resins, the immersion time significantly changed the color regardless of the solution. For artificial teeth resins, Cosmos TEMP 3D showed greater color changes in all solutions when compared to Duralay, except for 0.25% sodium hypochlorite. Chlorhexidine digluconate significantly changed the color of Duralay.

Biological and physicochemical implications of the aging process on titanium and zirconia implant material surfaces.

STATEMENT OF PROBLEM: Changes in physicochemical properties because of implant material aging and natural deterioration in the oral environment can facilitate microbial colonization and disturb the soft-tissue seal between the implant surfaces. PURPOSE: The purpose of this in vitro study was to investigate the effect of aging time on the physicochemical profile of titanium (Ti) and zirconia (ZrO2) implant materials. Further microbiology and cell analyses were used to provide insights into the physicochemical implications of biological behavior. MATERIAL AND METHODS: Disk-shaped specimens of Ti and ZrO2 were submitted to roughness, morphology, and surface free energy (SFE) analyses before nonaging (NA) and after the aging process (A). To simulate natural aging, disks were subjected to low-temperature degradation (LTD) by using an autoclave at 134 ºC and 0.2 MPa pressure for 20 hours. The biological activities of the Ti and ZrO2 surfaces were determined by analyzing Candida albicans (C. albicans) biofilms and human gingival fibroblast (HGF) cell proliferation. For the microbiology assays, a variance analysis method (ANOVA) was used with the Tukey post hoc test. For the evaluation of cellular proliferation, the Kruskal-Wallis test followed by Dunn multiple comparisons were used. RESULTS: Ti nonaging (TNA) and ZrO2 nonaging (ZNA) disks displayed hydrophilic and lipophilic properties, and this effect was sustained after the aging process. Low-temperature degradation resulted in a modest change in intermolecular interaction, with 1.06-fold for TA and 1.10-fold for ZA. No difference in biofilm formation was observed between NA and A disks of the same material. After 48 hours, the viability of the attached HGF cells was very similar to that in the NA and A groups, regardless of the tested material. CONCLUSION: The changes in the physicochemical properties of Ti and ZrO2 induced by the aging process do not interfere with C. albicans biofilm formation and HGF cell attachment, even after long-term exposure.