Denture Cleansers Significantly Affect Color Stability in TiO2-Infused Materials, Study Finds

In this in vitro study, 90 disc-shaped specimens of PMMA were divided into three groups based on the concentration of TiO2 NPs: 0wt%, 1wt%, and 2wt%. Each group was further divided into three subgroups, with each subgroup immersed in either distilled water, an oxygenating tablet (Corega), or 0.5% sodium hypochlorite. The specimens were then analyzed for color changes, surface roughness, and hardness values after 90 and 180 days of storage.

The study led to the following findings:

• Denture cleansers had a significant impact on color change in all groups compared to distilled water.
• After 90 days, specimens immersed in sodium hypochlorite exhibited a notably higher color change than those immersed in Corega.
• At the 0wt% concentration, sodium hypochlorite caused the color change to exceed the clinically acceptable threshold (∆E >3.7), indicating significant discoloration.
• The cleansers did not significantly alter the surface roughness of the samples containing TiO2 nanoparticles compared to the distilled water group.
• Immersion in hypochlorite resulted in significantly higher surface roughness for non-TiO2 nanoparticle samples at the 0wt% concentration.
• After 180 days, hypochlorite increased the surface roughness of non-TiO2 nanoparticle samples compared to those containing TiO2 nanoparticles.

Regarding surface hardness, the study found that the cleansers did not cause consistent changes across the different groups. The immersion time had a more substantial effect on surface roughness and hardness than the type of cleanser used. While the color change was notably influenced by the cleanser type, the surface properties, including roughness and hardness, remained relatively stable for TiO2 NP-infused samples.

"Denture cleansers significantly affected the color stability of PMMA containing TiO2 NPs, with sodium hypochlorite showing the most adverse effects. However, the cleansers did not notably alter surface roughness or hardness, particularly in TiO2 NP-infused samples," the researchers wrote.

"These findings suggest that while cleansers can affect the aesthetics of dentures, their impact on the mechanical properties of TiO2 nanoparticle-enhanced materials is less pronounced. Further studies are needed to explore the long-term effects of denture cleansers on these materials," they concluded.

Reference:

Ansarifard, E., Mohaghegh, M., Saadat, M. H., & Taghva, M. (2024). Effect of denture cleansers on color stability and surface properties of denture base material containing titanium dioxide nanoparticles. Journal of Prosthodontics, 34(1), 49-57. https://doi.org/10.1111/jopr.13793