These hypotheses will be addressed by collection of discarded devices from participants who are users of voice prostheses and registered at the Speech and Voice Clinic, Aberdeen Royal Infirmary (up to 27 people). Participants will be requested to donate discarded devices, mouthwash samples and simple data on recent antimicrobial or antacid treatments, and the use of dentures. The microbes colonising prostheses and contained within mouthwash samples will be isolated and identified and the association between microbial species and patient data over time will be analysed. Microbes will be stored as clinical isolates and used to test biofilm establishment and maintenance on silicones with modified surfaces designed to reduce biofouling.