Evaluation of hardness, surface roughness, and color stability of polymer materials after immersion in denture cleansers

Objective

The durability and color stability of denture base materials are crucial for long-term esthetic and functional success. Oral exposure can lead to surface deterioration and discoloration. While denture cleansers support hygiene, their effects on hardness, surface roughness, and color stability depend on the material. This study evaluated the impact of Efferdent, Corega, and Protefix on the hardness, surface roughness, and color stability of PEEK, PEKK, and 3D-printed denture base materials.

Materials And Methods

A total of 108 disk-shaped specimens (10 mm diameter, 2 mm thick) were prepared from PEEK, PEKK, and 3D-printed resin. The specimens were divided into three groups (n=36), and each material was exposed to three denture-cleaning solutions: Efferdent, Corega, and Protefix (n=12). Hardness, surface roughness (Ra, μm), and color change (ΔE00) were measured using a microhardness tester, profilometer, and spectrophotometer. Data were analyzed using two-way ANOVA, Tukey’s post-hoc test, and Robust ANOVA (P<0.05).

Results

Hardness reduction significantly differed among materials (P=0.011), with the highest loss in the 3D-printed material (22.18%). Denture cleansers had no significant effect on hardness (P=0.687). No significant interaction was found between material and cleansers regarding roughness and color stability. However, PEKK-Efferdent showed the highest roughness increase (10.60%), while the 3D-printed-Corega group exhibited the greatest color change (3.83). PEEK showed the lowest color change (1.41).

Conclusion

Materials and cleansers significantly influence denture properties. The 3D-printed material showed the highest hardness loss and color change, while PEKK demonstrated better mechanical resistance. Careful selection is essential for long-term denture durability and esthetics.