Microbiological Evaluation of Thermoplastic PETG Dental Appliances Related to Surface Characteristics

(1) Background: The adhesion and microbiological behaviour of thermoplastic PETG dental appliance surfaces is governed by roughness parameters. The aim of this research was to evaluate the antibiofilm activity of alkaline peroxide-based disinfectant in Candida albicans biofilms on thermoplastic PETG, related to artificial ageing and surface characteristics, on multiscale levels. (2) Methods: In the present study, two PETG materials were investigated: Crystal^® (Bio Art Dental Equipment, Sao Carlos, Brazil), noted as C, and Duran^® (Scheu-Dental GmbH, Iserlohn, Germany)-noted as D. Half of the specimens were thermally cycled (TC), resulting in four sample groups, as follows: C, CTC, D, and DTC. Surface roughness was evaluated on different scale topographies. The biofilms were grown on the surfaces. An alkaline peroxide-based disinfectant was used. Statistical analyses were performed. (3) Results: Related to nanoroughness, there are insignificant differences among materials or related to thermocycling. More irregular surfaces are associated with larger grain sizes. After thermocycling, micro-roughness values increase. Disinfectant activity decreases the amount of biofilm developed on the surfaces, significantly in the two groups, but is not correlated to the material and artificial ageing. (4) Conclusion: The impact of surface roughness (Ra) on biofilm constitution is controlled by different scale topographies.