Evaluation of the effects of denture disinfectants on the physical, mechanical, and microbiological properties of denture base materials fabricated using different manufacturing techniques

The aim of this study was to comparatively evaluate the changes in the physical, mechanical, and microbiological properties of PMMA-based denture base materials manufactured using conventional heat-polymerization, DLP, and LCD additive manufacturing techniques following the application of different chemical denture disinfectants. A total of 240 samples were prepared, with 80 specimens produced by each manufacturing method. Of these, 120 samples were used for surface roughness, surface hardness, and color stability evaluations, while the remaining 120 were used to assess Candida albicans biofilm formation. The specimens were immersed in Polident, 2% chlorhexidine, 1% sodium hypochlorite, and distilled water for 30 cycles over 6 days to simulate a 180-day cleaning protocol. Surface roughness was measured using a profilometer; surface hardness was measured using a Vickers microhardness tester, and color change was assessed with a spectrophotometer and calculated using the CIEDE2000 formula. Microbiological analysis was performed using crystal violet staining and CFU counting methods. Data were analyzed with SPSS version 22, with a significance level set at p<0.05. Material type significantly affected surface hardness, color stability, and Candida albicans biofilm formation (p<0.05). The DLP group exhibited the highest surface hardness values, while the LCD group showed the most favorable color stability. Materials produced via the conventional method demonstrated generally lower performance. Microbiologically, a statistically significant difference was observed only in the Polident group, where the conventional samples exhibited reduced biofilm accumulation; no significant differences were found among the other disinfectants. The results of this study indicate that both the manufacturing technique and the disinfectant type independently influence the properties of denture base materials. Additive manufacturing technologies generally provided superior physical and mechanical outcomes compared to the conventional method. Although limited in the literature, the LCD technique demonstrated promising performance in this study. These findings support the clinical applicability of digital manufacturing methods. Given that the effects of disinfectants varied depending on the material, the selection of cleaning agents should be tailored to the type of denture base material used.