Health risk of dental unit waterline system to dental patients – an issue of concern

Water delivered through dental unit waterline system (DUWS) is often reported contaminated with microbes dislodged from biofilm that forms within the tubing of a dental chair unit (DCU). ADM: The study aimed at evaluating the sanitary level of DCU water from a teaching dental clinic. Materials: The presence of pathogenic bacteria which include total coliforms, faecal coliforms, E. coli, faecal streptococci and P. aeruginosa were determined using conventional microbiological methods while PCR technique was used to identify other microbial contaminants. Result: pH of DCU water was found slightly acidic at pH 5.4-5.5 and the temperature was 23?C. Pathogenic contaminants were absent but the DCU water was highly loaded with Sphingomonas rhizogenes (17.9%), Sphingomonas dokdonesis (79.5%), Sphingomonas mucosissima (1.1%) and Methylobacterium radiotolerans (1.5%). The high load of microbes that exceeded 200 cfu/ml was of great concern as it failed to meet recommendation set by the American Dental Association.