Contribution of gingival conditions and bacterial levels in dental plaque and tongue coating on oral malodor of young subjects without periodontitis

Abstract

Aim: The aim of this study was to investigate the relationships between volatile sulfur compounds (VSC) levels in mouth air, gingival conditions and amount of oral microorganisms in samples of dental plaque and tongue coating in young subjects without periodontitis.
Subjects and methods: Eighteen systemic healthy young adults consisted of 13 males and 5 females (mean age: 22.7±3.1 yrs.) voluntarily participated in this study. After oral examinations, they were divided into 2 groups by their gingival conditions (gingivitis group and healthy group). At baseline, concentrations of hydrogen sulfide (H₂S) and methyl mercaptan (CH₃SH) in mouth air were measured using a gas chromatography after assessing the tongue coating score using the Winkel tongue coating index (WTCI). Subsequently, tongue coating were collected from the posterior of tongue dorsum and dental plaque was collected from the first molar lingual surfaces on both sides of the mandibular. Then, subjects cleaned their tongue thoroughly with soft toothbrush. After 3 days, the same measurement and sample collection were carried out. Oral samples were applied to real-time PCR assay to determine the amounts of total bacteria and Fusobacterium nucleatum. This study protocol was approved by the Ethical Committee of Iwate Medical University School of Dentistry.
Results: At baseline, CH₃SH concentration, and total amounts of bacteria in plaque samples were significantly higher in the gingivitis group. Three days after the tongue cleaning, H₂S concentration was reduced compaved to the baseline in the gingivitis group. For all subjects, there was a significant single correlation between amounts of total bacteria and F. nucleatum in dental plaque. Multiple linear regression analysis revealed that bleeding from gingiva on probing, periodontal pocket with 3 mm depth, WTCI and the amount of F. nucleatum were significantly related with VSC levels in mouth air.
Conclusion: VSC concentrations in mouth air are depend on gingival conditions and bacterial levels in dental and, as well as tongue coating.