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.