The assessment of methyl mercaptan, an important clinical marker for the diagnosis of oral malodor

Objective. This study aimed to determine the clinical assessment of volatile sulfur compound (VSCs) for the evaluation of noticeable oral malodor using gas chromatography (GC). Methods. The oral malodor of 127 adult patients was investigated using the organoleptic test and GC, and the relation between the organoleptic evaluation and VSCs were analyzed. Results. The optimum cut-off values of CH3SH, H2S and total VSC (CH3SH+H2S) to discriminate between the patients with and without noticeable oral malodor were obtained from ROC curves, and determined to be 0.44, 1.10 and 2.20 ng/10 ml, respectively. The logistic regression was analyzed for estimation of the association between an organoleptic evaluation greater than a slight level and the groups with CH3SH, H2S or total VSC with concentrations above the optimum cut-off value. Only CH3SH showed an independent association with noticeable oral malodor. Conclusions. It was evident that CH3SH was a more useful marker for the evaluation of oral malodor than H2S. Moreover, it appears CH3SH is the predominant causative factor of noticeable oral malodor.