Influence of various disinfection methods on the flexural strength of additively manufactured denture base resins: an in vitro study

With the advancement of technology for digitally fabricated removable dental prostheses, protocols for the disinfection of three-dimensional (3D)-printed dentures are lacking. Therefore, this study aimed to assess and compare the effects of different disinfection protocols on the flexural strength (FS) of 3D-printed denture base resins.

A total of 200 bar-shaped samples (64 × 10 × 3.3 mm) were fabricated via two types of 3D-printed denture base resins: DentaBase (DB) and Denture 3D+ (D). According to the disinfectant method, each resin sample was divided into five groups (n = 20). The samples were then further subdivided based on the duration of disinfection, either 90 days or 180 days. One control group was kept in water, while the other four groups were disinfected using a effervescent denture cleanser tablets (EDC), microwave (MW), ultraviolet light (UV), or ultrasonic (US). The flexural strength (FS) was measured. The collected data were statistically analyzed via three-way ANOVA, and post hoc Tukey’s test was used for data analysis (α = 0.05).

For Denture 3D+, FT significantly reduced FS at 90- and 180-day intervals (p < 0.05). UV disinfection maintained the highest FS at 90 days (72.1 MPa, p < 0.013); however, both the US and MW methods resulted in significant reductions by 180 days (p < 0.05). In the DentaBase, FT and MW disinfection caused significant FS reductions at 90 days (p < 0.001). By 180 days, FT, US, and MW disinfection methods led to significant decreases in FS (p < 0.001). However, UV light did not have a significant effect on FS at either point (p = 0.22).

UV disinfection proved to be the most suitable method for maintaining the mechanical integrity of 3D-printed denture base resins, while chemical, microwave, and ultrasonic methods should be used with caution due to their deteriorating effects on flexural strength.