Induction and inhibition of oral malodor

Abstract

Volatile sulfur compounds (VSCs) such as hydrogen sulfide (H2S) and methyl mercaptan (CH3SH) are the main components of oral malodor, and are produced as the end products of the proteolytic processes of oral microorganisms. The main pathway of proteolysis is the metabolism of sulfur‐containing amino acids by gram‐negative anaerobic bacteria. Gram‐positive bacteria may promote VSC production by gram‐negative anaerobes by cleaving sugar chains from glycoproteins and thus providing proteins. A large variety of bacteria within the oral microbiota are thought to be involved in the complex phenomenon of halitosis. Oral microbiota associated with a lack of oral malodor, oral microbiota associated with severe and H2S‐dominant oral malodor, and oral microbiota associated with severe and CH3SH‐dominant oral malodor have been distinguished through molecular approaches using the 16S rRNA gene. Pathological halitosis may primarily be addressed through treatment of causative diseases. In all cases, plaque control is the basis of oral malodor control, and dentifrices, mouthwashes, and functional foods play a supplementary role in addition to brushing. Recently, the use of natural ingredients in products tends to be favored due to the increase in antibiotic‐resistant strains and the side effects of some chemical ingredients. In addition, probiotics and vaccines are expected to offer new strategies for improving the oral conditions through mechanisms other than antibacterial agents.

The Role of Oral Microbiota in Intra-Oral Halitosis

“…The VSCs are the most essential substances responsible for malodor. They are products of metabolism of sulfur amino acids: methionine, cysteine, and homocysteine in the Gram-negative anaerobic bacteria [25,30,47,60]. Hydrogen sulfide and mercaptans are the principal end products [38].…”

Effects of eradication of Helicobacter pylori on oral malodor and the oral environment: a single-center observational study

“…There is disagreement as to whether H. pylori is present in the oral cavity. The bacterial communities in the oral cavity are highly complex and include a large number of VSC-producing bacteria [2]. The oral malodor associated with H. pylori is unlikely to be caused by its production of VSCs but, rather, by exacerbation of periodontitis and changes in the populations of some oral bacteria.…”

“…In 1985, Marshall et al [1] first reported oral malodor in subjects experimentally infected with H. pylori; however, the malodor was judged subjectively. Upper gastrointestinal disorders can cause oral malodor, but oral malodor is linked to the oral cavity in 90% of cases [2].…”

Rapid and accurate determination of trace volatile sulfur compounds in human halitosis by an adaptable active sampling system coupling with gas chromatography

“…It is caused by various volatile molecules including volatile sulfur compounds (VSCs), aromatic compounds, amines, and so on . Especially, VSCs, mainly including H 2 S, CH 3 SH, and CH 3 SCH 3 , are considered as the major components associated with halitosis , which accounts for about 90% of total halitosis . Besides, it has been reported that mostly (85%) of the pathology causing halitosis originated from the oral cavity , which has become a common phenomenon affecting the quality of social life .…”