Volatile sulphur compound levels and related factors in patients with chronic renal failure

Aims To analyse specific volatile sulphur compound(VSC) levels in a group of chronic renal failure (CRF) patients and determine the relationship between these VSC levels and organoleptic measurements, blood urea nitrogen (BUN) levels, dental and periodontal conditions, salivary flow rate, and tongue coating scores. Materials and Methods One examiner performed organoleptic and VSC measurements on fifty patients with CRF before and after haemodialysis (HD) and controls. DMFT and CPITN indexes, tongue coating scores, salivary flow rates were measured. Comparisons were performed using the Mann–Whitney U, Wilcoxon signed-ranks, and chi-square tests. Spearman correlation coefficient was used to analyse correlations. Results Before HD, the mean dimethyl sulphide level was 1.04 ± 1.20 in the CRF patients and 0.51 ± 0.65 in controls, with a significant difference. The mean hydrogen sulphide, methyl mercaptan and dimethyl sulphide levels in CRF patients were 1.47 ± 3.04, 1.03 ± 1.85, and 1.04 ± 1.20, respectively, before HD; and 0.53 ± 1.65, 0.48 ± 1.27, and 0.56 ± 0.85, respectively, after HD; with the differences being significant. Methyl mercaptan levels increased with an increase in HD duration. Tongue coating and organoleptic measurements were significantly correlated with methyl mercaptan. Conclusions Dimethyl sulphide is the main VSC in extraoral blood-borne halitosis; but methyl mercaptan may also contribute to this type of halitosis. A decreased salivary flow rate and an increased pH of the biofilm matrix may be a significant parameter for VSC levels in CRF patients.