A novel and visual test for oral malodour: first observations

A Literature Review and Framework Proposal for Halitosis Assessment in Cigarette Smokers and Alternative Nicotine-Delivery Products Users

Halitosis is a health condition which counts cigarette smoking (CS) among its major risk factors. Cigarette smoke can cause an imbalance in the oral bacterial community, leading to several oral diseases and conditions, including intraoral halitosis. Although the best approach to decrease smoking-related health risks is quitting smoking, this is not feasible for many smokers. Switching to potentially reduced-risk products, like electronic vapor products (EVP) or heated tobacco products (HTP), may help improve the conditions associated with CS. To date, there have been few systematic studies on the effects of CS on halitosis and none have assessed the effects of EVP and HTP use. Self-assessment studies have shown large limitations owing to the lack of reliability in the participants' judgment. This has compelled the scientific community to develop a strategy for meaningful assessment of these new products in comparison with cigarettes. Here, we compiled a review of the existing literature on CS and halitosis and propose a 3-layer approach that combines the use of the most advanced breath analysis techniques and multi-omics analysis to define the interactions between oral bacterial species and their role in halitosis both in vitro and in vivo. Such an approach will allow us to compare the effects of different nicotine-delivery products on oral bacteria and quantify their impact on halitosis. Defining the impact of alternative nicotine-delivery products on intraoral halitosis and its associated bacteria will help the scientific community advance a step further toward understanding the safety of these products and their potentiall risks for consumers.

The Role of Oral Microbiota in Intra-Oral Halitosis

Halitosis is a common ailment concerning 15% to 60% of the human population. Halitosis can be divided into extra-oral halitosis (EOH) and intra-oral halitosis (IOH). The IOH is formed by volatile compounds, which are produced mainly by anaerobic bacteria. To these odorous substances belong volatile sulfur compounds (VSCs), aromatic compounds, amines, short-chain fatty or organic acids, alcohols, aliphatic compounds, aldehydes, and ketones. The most important VSCs are hydrogen sulfide, dimethyl sulfide, dimethyl disulfide, and methyl mercaptan. VSCs can be toxic for human cells even at low concentrations. The oral bacteria most related to halitosis are Actinomyces spp., Bacteroides spp., Dialister spp., Eubacterium spp., Fusobacterium spp., Leptotrichia spp., Peptostreptococcus spp., Porphyromonas spp., Prevotella spp., Selenomonas spp., Solobacterium spp., Tannerella forsythia, and Veillonella spp. Most bacteria that cause halitosis are responsible for periodontitis, but they can also affect the development of oral and digestive tract cancers. Malodorous agents responsible for carcinogenesis are hydrogen sulfide and acetaldehyde.

Use of plastic-based analytical device, smartphone and chemometric tools to discriminate amines

Amine-based volatile compounds released by microorganisms offer an alternative diagnostic approach for the identification of foodborne pathogens.

Instrumental assessment of halitosis for the general dental practitioner

At the moment there are no clear protocols for the assessment of bad breath. An organoleptic evaluation is still the reference. To date there are several tools available to detect and quantify specific compounds related to halitosis. This paper reviews the available information on three sulphur monitors (OralChroma™ (CHM-1), Halimeter® and Breathtron®), in order to suggest guidance for the general dental practitioner. All three devices showed an acceptable correlation with organoleptic scores. The Halimeter® and Breathtron® seem the most appropriate devices for a general dental practitioner, because they are easy to handle. Because of its capacity of distinguishing between different sulphur compounds and due to its time-consuming and complicated use, the OralChroma™ (CHM-1) seems more suitable in a research environment.

Efficacy of different mouthrinse formulations in reducing oral malodour: a randomized clinical trial

AIMS

The aim of this study was to assess the efficacy of mouthrinses formulations in oral malodour.

MATERIAL & METHODS

This single-centre, double-blind, randomized, parallel group clinical trial compared the efficacy of Halita™ and meridol(®) with and without zinc lactate versus negative and positive control. Volunteers with confirmed oral malodour (18/group) rinsed with one mouthrinse during 7 days (15 ml, 2x/day for 1 min.). 15 min. after a first rinse (masking effect), and after 7 days (therapeutic effect) the change in organoleptic scores and level of sulphur compounds was recorded.

RESULTS

All rinses showed a masking effect (OLS 1 to 2 values reduced), only the rinses with antimicrobial ingredients showed a therapeutic effect (OLS 1 to 1.5 value less). The addition of zinc resulted in a more pronounced masking effect. Halita™ and meridol(®) with zinc showed the best therapeutic effect.

CONCLUSION

Although the masking effect of the rinses can be attributed partially to a dilution and the effect of aromas, the therapeutic effect should be linked to the anti-microbial action of active ingredients and counter action of zinc ions on VSC. A complete resolution of the unpleasant breath by additional mechanical intervention remains to be proven.

Injection of deuterated water into the pulmonary/alveolar circulation; measurement of HDO in exhaled breath and implications to breath analysis

The results of experiments are described in which a known quantity of sterile deuterated water is injected directly into the pulmonary circulation via the right internal jugular vein of several haemodialysis patients and the deuterium to hydrogen ratio, D/H, in the exhaled lung water was measured using the flowing afterglow mass spectrometry technique. The breath D/H abundance was measured in sequential breath exhalations before and after the injection, providing data that are sufficiently detailed to follow the production and loss rate of D/H in the exhaled breath. Thus, in principle, considering isotope dilution the volume of water in the lungs and pulmonary circulation can be derived. However, it is seen that the maximum abundance that the breath D/H reached was much lower than anticipated by considering the likely volume of blood/water in the pulmonary circulation and so it is deduced that either 'leakage' of the injected deuterated water rapidly occurs from the pulmonary to the systemic circulation and/or isotope exchange of deuterium with hydrogen along the bronchial tree efficiently occurs, thus reducing the D/H in the exhaled breath. This latter phenomenon has important implications to breath analysis in which it is often assumed that so-called alveolar breath concentrations of metabolites reflect blood/systemic levels. Detailed consideration of the breath D/H abundances when the deuterium is equilibrated amongst the total body water, TBW, of the patients, which occurs about 40 min after injection of the deuterated water, allows the TBW of the patients to be estimated.

Breaking paradigms: a new definition for halitosis in the context of pseudo-halitosis and halitophobia

It is known that almost one-third of patients who seeks treatment for bad breath do not have genuine halitosis. Halitosis can occur even in cases when the malodor is not perceived by those around the patient and can neither be confirmed by organoleptic tests, nor by sulfur portable monitor readings. In such cases, these patients have been considered as halitophobic or have pseudo-halitosis. The complaint might signal the existence of a chemosensory dysfunction. Factors associated with taste and smell perception can be potentially connected to the occurrence of oral malodor. The threshold values of volatile sulfur compounds that have been used to establish the diagnosis of genuine halitosis do not take into account that the patient may perceive low levels of these and of other volatile compounds through retronasal olfaction. The current concept of halitosis requires the presence of a signal that has been based on equipment results, from the olfactory perception of the examiners and of those who interact with the patient. Nevertheless, the concept does not encompass the symptoms of halitosis. This paper addresses some of the possible causes of chemosensory dysfunction and proposes a new definition for halitosis.

Bacterial lysine decarboxylase influences human dental biofilm lysine content, biofilm accumulation, and subclinical gingival inflammation

BACKGROUND

Dental biofilms contain a protein that inhibits mammalian cell growth, possibly lysine decarboxylase from Eikenella corrodens. This enzyme decarboxylates lysine, an essential amino acid for dentally attached cell turnover in gingival sulci. Lysine depletion may stop this turnover, impairing the barrier to bacterial compounds. The aims of this study are to determine biofilm lysine and cadaverine contents before oral hygiene restriction (OHR) and their association with plaque index (PI) and gingival crevicular fluid (GCF) after OHR for 1 week.

METHODS

Laser-induced fluorescence after capillary electrophoresis was used to determine lysine and cadaverine contents in dental biofilm, tongue biofilm, and saliva before OHR and in dental biofilm after OHR.

RESULTS

Before OHR, lysine and cadaverine contents of dental biofilm were similar and 10-fold greater than in saliva or tongue biofilm. After 1 week of OHR, the biofilm content of cadaverine increased and that of lysine decreased, consistent with greater biofilm lysine decarboxylase activity. Regression indicated that PI and GCF exudation were positively related to biofilm lysine after OHR, unless biofilm lysine exceeded the minimal blood plasma content, in which case PI was further increased but GCF exudation was reduced.

CONCLUSIONS

After OHR, lysine decarboxylase activity seems to determine biofilm lysine content and biofilm accumulation. When biofilm lysine exceeds minimal blood plasma content after OHR, less GCF appeared despite more biofilm. Lysine appears important for biofilm accumulation and the epithelial barrier to bacterial proinflammatory agents. Inhibiting lysine decarboxylase may retard the increased GCF exudation required for microbial development and gingivitis.