Influence of ageing on surface properties and biofilm adhesion on denture base resin material fabricated by different manufacturing techniques.

Objectives: To evaluate the effects of hydrothermal ageing on biofilm adhesion and surface properties of denture base resins fabricated via different techniques.

Materials and methods: Denture base resin samples were produced using the following manufacturing techniques: conventional cold polymerization (CP), heat polymerization (HP), CAD-CAM milling (CADm) and CAD-CAM printing (3D). The samples were tested before and after hydrothermal ageing (5000 cycles, 5 °C/55°C). The surface roughness was measured using atomic force microscopy (AFM), and the hydrophobicity was observed by measuring the water contact angle (WCA). Monomicrobial biofilm of Staphylococcus aureus and Candida albicans were formed and quantified before and after ageing using colony-forming units (CFUs/ml) and the MTT test. Statistical differences were evaluated using a two-way analysis of variance (ANOVA).

Results: Two-way ANOVA showed that ageing significantly influenced the roughness (p = 0.002). The highest roughness values before and after ageing were measured for 3D resin samples. The WCA values of 3D resin samples changed after ageing (p = 0.018). Amount and metabolic activity of monomicrobial biofilms were increased during ageing on all four tested denture base resins.

Conclusions: Ageing influenced the roughness and microbial adhesion on all tested denture base materials, regardless of the manufacturing method.

Clinical relevance: Finding support replacing dentures every five years due to increased biofilm adhesion post ageing.