Correlations between Hydrogen Sulfide and Methyl Mercaptan Levels and the Proportion of Porphyromonas Gingivalis in Patients with Periodontitis

The mixture of hydrogen sulfide and methyl in volatile sulfur compounds (VSCs) are known to cause oral malodor along with the action of microorganisms, particularly the periodontal pathogen Porphyromonas gingivalis (P. gingivalis). This study aimed to determine the correlation between hydrogen sulfide and methyl mercaptan levels and the proportion of P. gingivalis in the gingival crevicular fluid (GCF) and tongue coatings of patients with periodontitis. Clinical samples were collected from the GCF and tongues of 32 subjects, including periodontitis group and healthy individuals. Hydrogen sulfide and methyl mercaptan levels were measured using a gas chromatograph. Measurements of the probing pocket depth, bleeding on probing, and tongue coating scores were included as the diagnostic criteria. A pocket depth of ≥3 mm was taken into consideration. The quantities of P. gingivalis in the GCF and tongue coatings were evaluated by quantitative real-time polymerase chain reaction. Correlations between the levels of the two gases and the clinical parameters were analyzed using Spearman’s correlation test. Thirty-two samples collected were divided into three groups: healthy/control group (n = 6), periodontitis group A with a pocket depth 3–4 mm (n = 12), and periodontitis group B with a pocket depth of ≥5 mm (n = 14). Moderate positive correlations were found between both gases, hydrogen sulfide (r = 0,55; p<0,05) and methyl mercaptan (r = 0,432; p<0,05), and the proportion of P. gingivalis in the GCF. In the tongue coatings, hydrogen sulfide (r = 0,455, p<0,05), but not methyl mercaptan (r = 0,256;p>0,05), was correlated to P. gingivalis. Weak-to moderately-positive correlations between hydrogen sulfide and methyl mercaptan levels and the proportion of P. gingivalis were seen in the GCF and tongue coatings of the patients with periodontitis, which may be related to halitosis.