OBJECTIVETo establish a salivary sediment malodor system, and to evaluate the effect of several kinds of bacteria dedicated to the halitosis formation, hence to identify halitosis-correlated bacteria.

METHODSThe proportion of the supernatant and sediment, gained from centrifugal whole saliva, was adjusted to establish a salivary sediment malodor system incubated in facultative aerobic environment under 37 degrees C for 7 hours. The halitosis indexes in both gaseous phase and liquid phase were checked by direct sniffing, and volatile sulphur compounds (VSCs) and pH were determined by halimeter and glass electrode respectively between hours to evaluate the malodor formation. The suspended fluid of suspicious halitosis-correlated bacteria and non-halitosis-correlated bacteria and water control were introduced into the salivary sediment system incubated for 1 hour. The five groups were incubated in facultative aerobic environment under 37 degrees C in the residual hours. The halitosis indexes, VSCs and pH changes were recorded between hours.

RESULTSThe salivary sediment malodor system can simulate the metabolism of halitosis formation to produce halitosis. The odors of the suspicious halitosis-correlated bacteria introduced groups were higher than the non-halitosis-correlated bacteria and water control group.

CONCLUSIONWith its simple but fundamental manipulations, incubated whole saliva is a powerful model for study of the metabolism of the oral mixed microbial flora, malodor formation, and other oral diseases-related processes.