Negative correlation between oral malodour and numbers and activities of sulphate-reducing bacteria in the human mouth

ORGANOLEPTIC AND HALITOMETRIC ASSESSMENTS DO NOT CORRELATE WELL IN INTRA-ORAL HALITOSIS: A SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND

The gold standard method for diagnosing oral halitosis is the subjective organoleptic measurement. Device-supported methods are also widespread worldwide. The challenges and safety concerns around performing organoleptic measurements during pandemics and the diversity of measuring device alternatives raised our clinical question: which halitometer is the most suitable for diagnosing halitosis?

METHODS

This systematic review was registered in PROSPERO (ID CRD42022320024). The search was performed on March 23, 2022 in the following electronic databases: MEDLINE, Embase, Scopus, Web of Science, and CENTRAL. Adult populations with or without halitosis were included, and patients with systemic diseases were excluded. Organoleptic (subjective) measurement and the device-supported (objective) methods were compared; the primary outcome was the correlation coefficient, and the secondary was the specificity and sensitivity of the devices. QUADAS-2 and QUADAS-C were used to evaluate the risk of bias in the studies. Random-effects meta analyses were performed on the outcomes, and the secondary outcomes were plotted on a common ROC plot.

RESULTS

A total of 1231 records were found in the 5 databases. After the selection process, 76 articles were eligible for the systematic review, and 14,635 patients were involved in the qualitative analysis. The pooled Spearman's correlation coefficient (c.c.) for sulfide monitors was 0.65; 95% CIs: [0.53-0.74]; I2 = 95%, P < .01. The pooled Spearman's c.c. for portable gas chromatographs was 0.69; 95% CIs: [0.63-0.74]; I2 = 12%, P < .01. The pooled Spearman's c.c. for gas chromatographs was 0.76; 95% CIs: [0.67-0.83]; I2 = 0%, P < .01.

DISCUSSION

None of the most commonly used halitometers proved to be significantly superior to the others. Halimeter and OralChroma measurements did not correlate well with the organoleptic level of oral halitosis in adults. Therefore, better halitometers need to be developed as an alternative to organoleptic measurements.

Hydrogen Sulfide: From a Toxic Molecule to a Key Molecule of Cell Life

Hydrogen sulfide (H2S) has always been considered toxic, but a huge number of articles published more recently showed the beneficial biochemical properties of its endogenous production throughout all regna. In this review, the participation of H2S in many physiological and pathological processes in animals is described, and its importance as a signaling molecule in plant systems is underlined from an evolutionary point of view. H2S quantification methods are summarized and persulfidation is described as the underlying mechanism of action in plants, animals and bacteria. This review aims to highlight the importance of its crosstalk with other signaling molecules and its fine regulation for the proper function of the cell and its survival.

A timeline of hydrogen sulfide (H2S) research: From environmental toxin to biological mediator

The history of H2S - as an environmental toxin - dates back to 1700, to the observations of the Italian physician Bernardino Ramazzini, whose book "De Morbis Artificum Diatriba" described the painful eye irritation and inflammation of "sewer gas" in sewer workers. The gas has subsequently been identified as hydrogen sulfide (H2S), and opened three centuries of research into the biological roles of H2S. The current article highlights the key discoveries in the field of H2S research, including (a) the toxicological studies, which characterized H2S as an environmental toxin, and identified some of its modes of action, including the inhibition of mitochondrial respiration; (b) work in the field of bacteriology, which, starting in the early 1900s, identified H2S as a bacterial product - with subsequently defined roles in the regulation of periodontal disease (oral bacterial flora), intestinal epithelial cell function (enteral bacterial flora) as well as in the regulation of bacterial resistance to antibiotics; and (c), work in diverse fields of mammalian biology, which, starting in the 1940s, identified H2S as an endogenous mammalian enzymatic product, the functions of which - among others, in the cardiovascular and nervous system - have become subjects of intensive investigation for the last decade. The current review not only enumerates the key discoveries related to H2S made over the last three centuries, but also compiles the most frequently cited papers in the field which have been published over the last decade and highlights some of the current 'hot topics' in the field of H2S biology.

Detection and measurement of oral malodor in chronic periodontitis patients and its correlation with levels of select oral anaerobes in subgingival plaque

Introduction:

Oral malodor is generally ascribable to oral microbial putrefaction generating malodorous volatile sulfur compounds. The aim of the present study is to correlate organoleptic recordings with a small handheld portable volatile sulfide monitor and periodontal clinical parameters and correlate the levels of halitosis causing bacteria in plaque between baseline, 1-week, and 1-month.

Materials and Methods:

A total of 20 systemically healthy subjects with self-reported halitosis were subjected to organoleptic examination and FitScan^®. Subgingival plaque samples for anaerobic culturing were harvested followed by an assessment of plaque index (PI), gingival bleeding index (GBI), and pocket probing depth. Data derived were subjected to statistical analysis using Wilcoxon signed rank test and Spearman's rank test (P < 0.05).

Results:

No correlation was seen between organoleptic measurements and portable volatile sulfide monitor at any time interval. There was a statistically significant (P < 0.05) correlation between the scores of PI, gingival index, GBI, and myeloproliferative disease with organoleptic readings at all-time intervals. Anaerobic culture has shown to identify Fusobacterium species, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia. However, no correlation could be established in between total microbial load with organoleptic and FitScan^® reading at any time interval (P < 0.05).

Conclusion:

Significant correlation could be established between organoleptic readings and periodontal parameters.

Salivary nitrate and nitrite may have antimicrobial effects on Desulfovibrio species

The antibacterial effects of salivary nitrate/nitrite on the growth of three Desulfovibrio species were examined. The bacteria did not grow on plates with ≥ 0.2 mM nitrate or ≥ 1.0 mM nitrite. They were also incubated in filter-sterilized saliva. D. desulfuricans was reduced on the order of >10(2) compared with the control solution (phosphate-buffered saline) in nine out of the 10 participants.

Detection of Sulphate-Reducing Bacteria and Others Cultivable Facultative Bacteria in Dental Tissues

AIM

To detect for the presence of sulphate-reducing bacteria (SRB) and evaluate the possible association between SRB and cultivable facultative bacterial of oral sites with different periodontal conditions.

METHODS

The study was carried out on 9 samples from different oral sites in 8 patients (two samples were collected from the same patient). Material was collected using modified Postgate E culture medium, indicated for the growth and isolation of SRB. In addition, a reducing solution for anaerobic bacteria was used as a transport solution for facultative bacteria and identified by polymerase chain reaction amplification (PCR) and sequencing of the 16S rRNA gene.

RESULTS

SRB was found in 3 patient samples: the first in a root fragment, the second in a root fragment and a healthy tooth with vertical bone loss and a mobility degree of 3; and the third in a healthy tooth extracted for orthodontic treatment. In the final patient, the cultivable facultative species Lactobacillus casei was identified. Other facultative bacterial species were identified in patient 5 (Kurthia Gibsonii) and patient 7 (Pseudomonas aeruginosa).

CONCLUSIONS

The detection of SRB in different dental tissues with distinct periodontal features demonstrated that new studies need to be developed in order to determine the true role of SRB in the oral microbiota. In addition, it was possible to verify the presence of Lactobacillus casei together with SRB in one sample.

One-pot microbial method to synthesize dual-doped graphene and its use as high-performance electrocatalyst

A novel strategy to synthesize nitrogen (N) and sulfur (S)-doped graphene (G) is developed through sulfate-reducing bacteria treating graphene oxide (GO). The N, S-doped G demonstrates significantly improved electrocatalytic properties and electrochemical sensing performances in comparison with single-doped graphene due to the synergistic effects of dual dopants on the properties of graphene.

Detection of sulphate-reducing bacteria in human saliva

OBJECTIVE

The aim of the current study was to investigate the presence of sulphate-reducing bacteria (SRB) in human saliva and correlate with oral and systemic conditions.

METHODS

Saliva samples were collected from 118 patients and inoculated in 2 ml of modified Postgate's E medium culture. After 28 days of incubation at 30°C the presence of SRB was identified by the production of sulphide.

RESULTS

Of 118 saliva samples collected, 35 were positive for the presence of SRB. Three positive samples were randomly chosen to identify the species of SRB by PCR and sequenced. The three selected samples were identified as Desulfovibrio fairfieldensis, Desulfovibrio desulfuricans and Raoultella ornithinolytica. Gastritis (14.4%) was the most prevalent systemic disease, followed by diabetes (3.4%), while periodontitis (11%) and traumatic fibroma (4.2%) were the oral manifestations most frequently found. A bivariate analysis was performed to examine for the presence of SRB and the most prevalent systemic and oral manifestations. Only periodontitis showed a statistically significant association (p = 0.0003).

CONCLUSIONS

The results showed SRB can be found in oral microbiota of healthy patients. Regarding the several conditions studied, there was a higher prevalence of SRB in patients with gastritis and patients with periodontal disease, with a possible correlation between the presence of SRB in the oral microbiota and periodontal disease.

Microbial volatile compounds in health and disease conditions

Microbial cultures and/or microbial associated diseases often have a characteristic smell. Volatile organic compounds (VOCs) are produced by all microorganisms as part of their normal metabolism. The types and classes of VOC produced is wide, including fatty acids and their derivatives (e.g. hydrocarbons, aliphatic alcohols and ketones), aromatic compounds, nitrogen containing compounds, and volatile sulfur compounds. A diversity of ecological niches exist in the human body which can support a polymicrobial community, with the exact VOC profile of a given anatomical site being dependent on that produced by both the host component and the microbial species present. The detection of VOCs is of interest to various disciplines, hence numerous analytical approaches have been developed to accurately characterize and measure VOCs in the laboratory, often from patient derived samples. Using these technological advancements it is evident that VOCs are indicative of both health and disease states. Many of these techniques are still largely confined to the research laboratory, but it is envisaged that in future bedside 'VOC profiling' will enable rapid characterization of microbial associated disease, providing vital information to healthcare practitioners.

Prevalence of halitosis in young male adults: a study in swiss army recruits comparing self-reported and clinical data

BACKGROUND

Sound epidemiologic data on halitosis are rare. We evaluated the prevalence of halitosis in a young male adult population in Switzerland using a standardized questionnaire and clinical examination.

METHODS

Six hundred twenty-six Swiss Army recruits aged 18 to 25 years (mean: 20.3 years) were selected as study subjects. First, a standardized questionnaire focusing on dental hygiene, self-reported halitosis, smoking, and alcohol consumption was filled out by all participants. In the clinical examination, objective values for the presence of halitosis were gathered through an organoleptic assessment of the breath odor and the measurement of volatile sulfur compounds (VSCs). Additionally, tongue coating, plaque index, and probing depths were evaluated for each recruit.

RESULTS

The questionnaire revealed that only 17% of all included recruits had never experienced halitosis. The organoleptic evaluation (grades 0 to 3) identified eight persons with grade 3, 148 persons with grade 2, and 424 persons with grade 1 or 0. The calculation of the Pearson correlation coefficient to evaluate the relationship among the three methods of assessing halitosis revealed little to no correlation. The organoleptic score showed high reproducibility (kappa = 0.79). Tongue coating was the only influencing factor found to contribute to higher organoleptic scores and higher VSC values.

CONCLUSIONS

Oral malodor seemed to pose an oral health problem for about one-fifth of 20-year-old Swiss males questioned. No correlation between self-reported halitosis and organoleptic or VSC measurements could be detected. Although the organoleptic method described here offers a high reproducibility, the lack of correlation between VSC values and organoleptic scores has to be critically addressed. For further studies assessing new organoleptic scores, a validated index should always be included as a direct control.

A review of the current literature on aetiology and measurement methods of halitosis

OBJECTIVES

This work reviews the current knowledge of aetiology and measurement methods of halitosis.

DATA

Halitosis is an unpleasant or offensive odour emanating from the breath. The condition is multifactorial and may involve both oral and non-oral conditions.

SOURCES

A private, monthly with keywords halitosis, malodo(u)r, (a)etiology, measurement, and management from Medline and Pubmed updated database of literature was reviewed.

CONCLUSIONS

In approximately 80-90% of all cases, halitosis is caused by oral conditions, defined as oral malodour. Oral malodour results from tongue coating, periodontal disease, peri-implant disease, deep carious lesions, exposed necrotic tooth pulps, pericoronitis, mucosal ulcerations, healing (mucosal) wounds, impacted food or debris, imperfect dental restorations, unclean dentures, and factors causing decreased salivary flow rate. The basic process is microbial degradation of organic substrates. Non-oral aetiologies of halitosis include disturbances of the upper and lower respiratory tract, disorders of the gastrointestinal tract, some systemic diseases, metabolic disorders, medications, and carcinomas. Stressful situations are predisposing factors. There are three primary measurement methods of halitosis. Organoleptic measurement and gas chromatography are very reliable, but not very easily clinically implemented methods. The use of organoleptic measurement is suggested as the 'gold standard'. Gas chromatography is the preferable method if precise measurements of specific gases are required. Sulphide monitoring is an easily used method, but has the limitation that important odours are not detected. The scientific and practical value of additional or alternative measurement methods, such as BANA test, chemical sensors, salivary incubation test, quantifying beta-galactosidase activity, ammonia monitoring, ninhydrin method, and polymerase chain reaction, has to be established.

Effect of different mouthrinses on morning breath

BACKGROUND

Morning breath odor is an often-encountered complaint. This double-blind, crossover, randomized study aimed to examine the bad breath-inhibiting effect of 3 commercially available mouthrinses on morning halitosis during an experimental period of 12 days without mechanical plaque control.

METHODS

Twelve medical students with a healthy periodontium refrained from all means of mechanical plaque control during 3 experimental periods of 12 days (with intervening washout periods of at least 3 weeks). A professional oral cleaning preceded each period. During each experimental period, as the only oral hygiene measure allowed, the students rinsed twice a day with one of the following formulations in a randomized order: CHX-Alc (a 0.2% chlorhexidine [CHX] solution); CHX-NaF (CHX 0.12% plus sodium fluoride 0.05%); or CHX-CPC-Zn (CHX 0.05% plus cetylpyridinium chloride 0.05% plus zinc lactate 0.14%). After 12 days, morning breath was scored via volatile sulfur compound (VSC) level measurements of the mouth air and organoleptic ratings of the mouth air, the expired air, and a scraping of the tongue coating. At the 12-day visit, a questionnaire (subjective ratings) was completed and samples taken from both the tongue coating and the saliva for anaerobic and aerobic culturing and vitality staining. The de novo supragingival plaque formation was also recorded. All parameters were correlated with the baseline registrations.

RESULTS

Although oral hygiene during the 3 experimental periods was limited to oral rinses, bad breath parameters systematically improved, with the exception of a slight increase in VSC levels while using CHX-Alc, a finding which was associated with the direct influence of the CHX on the sulfide monitor. The oral microbial load after the use of CHX-NaF remained unchanged, while for the CHX-Alc and CHX-CPC-Zn, significant reductions in both aerobic and anaerobic colony forming units (CFU)/ml were noticed in comparison with baseline data for both tongue coating and saliva samples. The composition of microflora, on the other hand, did not reveal significant changes. The supragingival plaque formation was inhibited, in descending order, by CHX-Alc, CHX-CPC-Zn, and CHX-NaF. The subjective scores for the rinses indicated a higher appreciation for CHX-CPC-Alc and CHX-NaF because of a better taste and fewer side effects.

CONCLUSIONS

The results of this study demonstrate that morning halitosis can be successfully reduced via daily use of mouthrinses. CHX-Alc and CHX-CPC-Zn mouthrinses result in a significant reduction of the microbial load of tongue and saliva.

Decrease of sulfate-reducing bacteria after initial periodontal treatment

Sulfate-reducing bacteria (SRB) are associated with periodontitis, but it is unknown if elimination of these potential pathogens accompanies clinical improvement. This longitudinal study examined the occurrence of SRB and clinical effects following scaling and root planing. In this study, the presence of periodontal SRB was determined in 38 selected patients before and six months after mechanical therapy. SRB were detected by the enrichment culture technique. Mechanical periodontal treatment resulted in elimination of SRB in 89% of the patients, and 95% of the sites (n = 76). SRB were significantly reduced in patients with progressive, adult, and refractory periodontitis. The elimination of SRB was accompanied by clinical improvement. The mean gain of attachment of these pockets was 3 mm (p < 0.001). The reductions in pocket depth (p < 0.001) and bleeding were significant (p < 0.001). Persistence of SRB correlated with the initial pocket depth (p < 0.02) and attachment level (p < 0.02), and with bleeding of the site after treatment (p < 0.05). In conclusion, mechanical debridement is generally effective for the elimination of SRB.