Evaluation of sulcular sulphide level monitoring using a portable sensor system

Volatile sulphur compounds (VSC) such as hydrogen sulphide and methyl mercaptan are toxic bacterial metabolites considered to contribute to the progression of periodontitis. However, the quantitative determination of sulcular VSC concentration requires costly time-consuming laboratory methods limiting its evaluation in large clinical trials. Recently, a portable monitor with a sulphide microsensor has been developed to measure sulcular VSC levels (SU). This cross-sectional study evaluated 1) the clinical usage of the sulphide sensor system, 2) the reproducibility of SU-measurements, 3) the distribution of SU-values in periodontal health and disease and 4) the relationship between SU and clinical parameters documenting periodontal disease severity.

The specificity, the measuring range and the reproducibility of the sensor system were tested with reference solutions in vitro. 10 probands with healthy gingiva, 23 patients with gingivitis and 30 patients with chronic periodontitis were examined recording periodontal parameters (clinical attachment loss, CAL, probing depth, PD, bleeding on probing intensity BI, plaque and gingival index PI, GI) and sulcular sulphide level (SU) measured by the portable monitor as a digital score ranging from 0.0 (< 10 superset -6 M of S2-) to 5.0 (10 superset -2 M of S superset 2-) in increments of 0.5.

The in vitro testing confirmed the sensor s specificity for sulphide ions. The intraexaminer agreement (Pearson correlation coefficient) was 0.91 between two measurements (p < 0.05). However, positive SU-values decreased with measurement repetition due to the volatility of the sulphur compounds. SU and the percentage of positive SU-values per patient were correlated with disease severity. There were no positive SU-values in healthy probands, a mean SU of 0.11 +/- 0.08 in gingivitis and of 0.22 +/- 0.15 in periodontitis (p <0.001). SU was significantly correlated with PD in gingivitis, PD and CAL in periodontitis and the bleeding index in the analysis of all data.

The portable sulphide monitor is a reliable method for the chairside determination of sulcular sulphide level in periodontal disease and in spite of its limitations a valuable supplementation of traditional clinical examination methods. It offers the possibility of relating in vitro results on the toxicity of VSC to clinical findings and might provide new insight into the impact of sulcular sulphide on the pathophysiology of periodontitis.