bluuebunny/crossref_metadata_2025 huggingface dataset:
Lethal photosensitization of oral pathogens via red‐filtered halogen lamp
Authors: Krespi YP , Slatkine M , Marchenko M , Protic J
Published: March 2005

Objective of investigation:  The ability of laser irradiation in the presence of photosensitizing agent to induce lethal effect on oral bacteria is well documented. We designed an in‐vitro experiment to achieve phototoxic results on two common oral pathogens, using a high intensity, red filtered halogen lamp. Our goal was to determine the minimum duration of light exposure and drug dilution to achieve at least 50% reduction in bacteria counts.

Methods:  Two common oral pathogens, Porphyromonas gingivalis and Prevotella intermedia were used in experiments. The source for light energy was a continuous working, high intensity, red filtered, halogen lamp (HL) with light transmitted through a flexible light guide over petri dishes containing live bacteria. Microorganisms were exposed to light for 5, 10 and 20 min. Methylene Blue (MB) in concentrations of 0.1, 0.075, 0.05, 0.025 and 0.01% was used as a photosensitizing agent. Light energy alone and MB alone was used as controls.

Results and discussion:  Optimum lethal photosensitization (50% or more bacteria killing) of oral pathogens was achieved using halogen light illumination for 5 min and longer with 0.05% MB or exposure to light for 20 min in the presence of 0.025 and 0.01% MB. Light exposure of 20 min in the absence of MB was not effective in killing bacteria. In the absence of light, MB at concentrations of 0.025 and 0.001% was not effective. Reduction of bacteria with the use of 0.05% MB alone was also insignificant. However, 0.075 and 0.1% MB, even in the absence of light was found to be bacteriocidal.

Conclusions:  Our in‐vitro data indicate that we were able to achieve lethal photosensitization of two common oral pathogens with high intensity red filtered HL in the presence of diluted MB. In this era of increased incidence of antibiotic resistance, bacterial killing with laser or light energy in the presence of photosensitizing agent can prove to be a valuable treatment modality.
Is transmission of bacteria that cause halitosis from pets to humans possible?
Authors: Iwanicka‐Grzegorek E , Kepa J , Lipkowska E , Michalik J , Pierzynowska E , Placha R
Published: March 2005

Objective: Bacteria that cause halitosis naturally colonize the animal's mouth. The possibility of transmission of these bacteria from pets to human is an intriguing question. Therefore, the possible correlation between halitosis and regular contact of dental patients with pet animals was the aim of the presented study.

Materials and methods: The study covered 84 patients suffering from halitosis and 40 healthy controls aged 20–62 years. Each person completed a questionnaire and was then examined for organoleptic score, volatile sulphur compounds (VSC) and evaluation of low molecular mass amines in saliva by a ninhydrin colorimetric reaction. Halitosis was diagnosed if the average level of VSC was 125 ppb and the organoleptic measurement using a 0–5 point scale was 2. Statistical analysis was performed using Wilcoxon's and chi‐square tests.

Results: The results showed that among the halitosis group over 80% of patients had reported having pets in childhood and over 70% owned a pet at present. In the control group results are 47 and 40%, respectively. Analysis showed a significant correlation between frequency of halitosis and regular contact with pets at present (P < 0.001) or in childhood (P < 0.001).

Conclusion: Pets (dogs, cats) owned in childhood or at present may transmit bacteria that cause halitosis.
O12  Volatile markers of oral malodor in the breath
Authors: Phillips M , Nachnani S , Cataneo RN , Greenberg J
Published: March 2005

Objective  To identify the chemical composition of volatile organic compounds (VOCs) in the breath of patients with oral malodor.

Methods  Patients with strong offensive oral malodor (n = 4) donated oral cavity breath into inflatable bags lined with polyethylene. Patients had grade ≥3 oral malodor on an organoleptic scale (0–5) as assessed by trained organoleptic judges. In the laboratory, each bag was heated to 38°C to vaporize condensed water. 150 ml breath was then removed from the bag and injected on to a sorbent trap (Carbotrap, Supelco) in order to capture the VOCs. Samples were analyzed by automated thermal desorption with gas chromatography and mass spectroscopy (ATD/GC/MS) and the VOCs were identified from a computer‐based library of mass spectra.

Results and discussion  The 10 most abundant VOCs observed were (in descending order): methylbenzene, 2,2‐dimethyldecane, 2,2,3,3‐tetramethylbutane, 2‐propanone, 3‐methyl‐5‐propylnonane, methylcyclohexane, 3‐methylhexane, 2‐methyl‐1‐propene, ethanol and methylcyclopentane. These VOCs may have been produced by bacterial metabolism.

Conclusions  Assay with ATD/GC/MS identified the most abundant VOCs in oral cavity breath of patients with strong offensive oral malodor. Potential clinical applications of this technique include identification of the VOCs responsible for oral malodor in individual patients, and monitoring the effectiveness of treatment to reduce the abundance of these VOCs.
O13  Trimethylaminuria, diet and a ‘fish‐like’ odour
Authors: Mitchell SC , Smith RL
Published: March 2005

Trimethylaminuria, also known colloquially as the fish malodour syndrome, is a metabolic disorder characterized by the presence of abnormal amounts of the dietary‐derived tertiary amine, trimethylamine, in the urine, sweat, expired air and other bodily secretions. Trimethylamine usually undergoes metabolism to form the innocuous metabolite, trimethylamine N‐oxide. However, ‘greater‐than‐normal’ amounts of trimethylamine may accumulate within the body owing to a mismatch in the enzyme's capacity to undertake this N‐oxidation reaction and the substrate load it has to process. Trimethylamine itself is a volatile substance and has the powerful aroma of rotting fish, conferring upon the sufferer a highly objectionable body odour, which can be destructive to the personal, social and work life of the affected individual. As more cases of this condition have been uncovered it has become apparent that there are several sub‐types of this disorder, falling into two major categories, and this has allowed a clearer picture to emerge. First, there are those forms that are related to a dysfunction of the normal enzyme (flavin‐containing monooxygenase 3; FMO3) activity owing to genetic, hormonal or inhibitory chemical influences. Secondly, there are those forms arising from substrate overload of enzyme activity (either in a normal or depressed state) such as an excess of dietary precursors or variations of gut microflora resulting in enhanced liberation of trimethylamine. Clearly, certain aspects of these two categories are intimately entwined and several factors may act together to give rise to the disorder. In recent years much progress has been made at all levels in our understanding of this condition. This presentation will summarize this progress, draw attention to the different types of the condition and highlight aspects that require further investigation.

S.C. Mitchell, R.L. Smith (2001). Trimethylaminuria: the fish malodour syndrome. Drug Metabolism and Disposition29: 517–521.

J.R. Cashman, K. Camp, S.S. Fakharzadeh, P.V. Fennessey, R.N. Hines, O.A. Mamer, S.C. Mitchell, G. Preti, D. Schlenk, R.L. Smith, S.S. Tjoa, D.E. Williams, S. Yannicelli (2003). Biochemical and clinical aspects of the human flavin‐containing monooxygenase form 3 (FMO3) related to trimethylaminuria. Current Drug Metabolism4: 151–170.
O14  In vitro models for oral malodor
Authors: Greenman J , Spencer P , Mckenzie C , Saad S
Published: March 2005

We start with a description of what we mean by a model and introduce the idea of using different types of model to answer different types of questions. A model is a representation of some real phenomena and contains aspects or elements of the real system to be modelled. The model reflects (or duplicates) the type of behaviour (or mechanisms) seen in the real system. The main characteristic of any model is the mapping of elements or parameters found in the system being studied (e.g. tongue dorsum biofilm in situ) on to the model being devised (e.g. laboratory perfusion biofilm). Such parameters include correct physico‐chemical (abiotic) conditions as well as biotic conditions that occur in both model and reality. The main purpose of a model is to provide information that better explains the processes observed or thought to occur in the real system. Such models can be abstract (mental, conceptual, theoretical, mathematical or computational) or ‘physical’ e.g. in the form of a real disaggregated in vitro system or laboratory model. A wide range of different model systems have been used in oral biofilm research. These will be briefly reviewed with special emphasis on those models that have contributed most to knowledge in breath odour research. The different model systems used in breath odour research will be compared with each other regarding their advantages, disadvantages and main applications. Finally, the requirements for developing an overall ‘bad breath model’ from considering the processes as a whole (real oral cavity; substrates in saliva;, biotransformation; odour gases in the breath) and extending this to the detection of malodour by the human nose (and all stages in between) will be outlined and discussed.
O15  Use of molecular identification techniques to study oral microbes and microcosms
Authors: Spratt D
Published: March 2005

Over the last 100 years traditional culturing techniques have shaped our understanding of the oral microflora. However it is generally accepted that around 50% of the oral microbiota is unculturable. Recent advances in molecular biology have given rise to numerous techniques which form the basis of a number of strategies that can be used to detect and identify micro‐organisms to levels and specificities unattainable by conventional culture techniques. The molecular biology basis of these techniques can be conveniently split in to two broad groups. (1) DNA hybridization techniques: these are used for slot blot and checkerboard analysis and when combined with microscopy form a powerful visualization technique – fluorescent in situ hybridization (FISH). (2) PCR based approach: development of the PCR concept has lead to techniques such as global PCR, specific PCR, nested PCR, PCR‐cloning, reverse transcriptase PCR, real time PCR and PCR‐DGGE. The above techniques can usually be used on their own however they provide even more power when used in conjunction with each other. For example PCR‐cloning or PCR‐DGGE can be used to analyse a whole community. From this, un‐named or unculturable taxa can be ‘identified’ and targeted for further characterisation. This may involve the use of PCR specific for the taxon in question, to survey a large number of samples to obtain some prevalence data or in a real time setting to quantify the taxon. Indeed, a fluorescently labelled probe could be synthesized and used to visualize the taxon in an appropriate environmental sample or microcosm using confocal laser scanning microscopy. All the above techniques add up to a powerful set of tools which if selected appropriately have the potential to revolutionize our understanding of the microbial world.
O16  Organoleptic assessment of pure odour compounds representative of the metabolic end‐products of oral microbes
Authors: Spencer PS , Greenman J , Saad S
Published: March 2005

We have measured various production rates of volatile compounds in tongue scrape cell suspensions, oral biofilm models and the oral cavity in situ and wish to relate these to equivalent levels of oral malodour as assessed by the human nose.

Objectives  To assess the relationship between measured concentrations of pure odourants and resultant organoleptic scores (using a defined 0–5 score).

Methods  Seven odour judges, all with experience of organoleptic assessment, were used in this study for all experiments carried out at a single site (UWE, Bristol). A wide range of pure odourants were prepared at a range of concentrations (from a stock of 0.1 M) and were dispensed as 12 ml volumes into ‘universal’ bottles (24 ml capacity) leaving a headspace of 12 ml. The bottles were secured with rubber‐lined metal caps, labelled with a randomized code and were presented to the odour judges for assessment using the Rosenberg 0–5 scale. The volatile sulphur compounds (H2S and CH3SH) were presented as gases with dilutions being prepared through a dynamic gas flow rig (using oxygen free nitrogen as the diluent) and presented to the odour judges at a flow rate of 200 ml min−1. Group means of determinations for each odourant were plotted against log10 of the concentration. Linear regression analysis was used to measure the gradient, 95% CI, and the scatter of the points around the gradient (R2 value).

Results  Organoleptic scores were proportional to the log10 concentration of odourant. Detection thresholds (expressed as mol dm‐3) were skatole (7.2 × 10−13) < methyl mercaptan (1.0 × 10−11) < trimethylamine (1.8 × 10−11) < butyrate (2.3 × 10−10) < hydrogen sulphide (6.4 × 10−10) < putrescine (9.1 × 10−10) < dimethyldisulphide (5.9 × 10−8). Hydrogen sulphide showed highest olfactory power whilst putrescine was the lowest.

Conclusions  The olfactory response is exponential in nature. For any single compound, its contribution to malodour depends on: odour (olfactory) power, threshold (of detection) and volatility in addition to the concentration. It is now possible to relate production rates of VC's in models to typical levels of oral malodour perceived by the human nose.
O17  Effect of Probiotic Streptococcus salivarius K12 on oral malodour parameters
Authors: Burton JP , Chilcott CN , Moore CJ , Tagg JR
Published: March 2005

Objective  Recent non‐cultural‐based studies of the oral microbiota indicate that some subjects with halitosis are less likely to have the usually predominant commensal bacterium Streptococcus salivarius detected [J Clin Microbiol (2003) 41(2): 558–563.]. The aim of this study was to determine whether the oral delivery of viable bacteriocin‐producing S. salivarius could influence the composition of the oral microbiota implicated in halitosis and impact upon measurable parameters of malodour.

Methods  Thirteen subjects with volatile sulphur compound (VSC) breath readings of >200 ppb on two separate visits were recruited for the study. The subjects undertook a 3‐day regimen of chlorhexidine rinses followed at intervals by the sucking of four lozenges, each containing >1 × 109 colony forming units of the bacteriocin‐producing S. salivarius K12. The subjects then ceased using the chlorhexidine and took just two lozenges per day for a total of 2 weeks. At each pre‐treatment visit and at 1 and 2 weeks after treatment initiation the subjects were tested for VSC and both saliva samples and tongue swabs were subjected to BANA testing, microbial culture and PCR‐denaturing gradient gel electrophoresis (PCR‐DGGE) analysis. All measurements were taken in the morning prior to the subjects eating, drinking or using any oral care. The ability of the bacteriocins produced by S. salivarius K12 to inhibit bacteria implicated in halitosis was tested in vitro by deferred antagonism tests using pure cultures and saliva samples.

Results and discussion  The VSC levels of eight subjects were significantly lower when tested 1 and 2 weeks after commencing treatment, three subjects had lower readings only after 1 week and two subjects maintained high levels throughout the study. Reduction of BANA activity and changes in the PCR‐DGGE profiles occurred in most subjects following treatment. In deferred antagonism studies, S. salivarius K12 inhibited some of the bacterial species implicated in halitosis, and significantly inhibited black‐pigmented colony types in saliva samples.

Conclusions  The replacement of bacteria implicated in halitosis with the bacteriocin‐producing commensal bacterium S. salivarius K12 appears to provide an alternative therapy for the long‐term reduction of halitosis.
O19  H2S inhibits O2− scavenger and causes oxidative damage in vivo
Authors: Yaegaki K , Qian W , Lee W , Choi D
Published: March 2005

Objective  Volatile sulphur compounds (VSCs), namely hydrogen sulfide and methyl mercaptan have been demonstrated to initiate or progress periodontal disease by increasing the permeability of sulcal epithelium and the degradation of extracellular matrices. Superoxide dismutase (SOD) is one of the most important antioxidative enzymes in intracellular protection against superoxide free radicals which may cause cancer or aging process. The objectives of this study were to demonstrate that hydrogen sulfide, a major contributor to oral malodor, inhibits SOD activity, and to determine if VSCs cause oxidative damage.

Methods  Cu,Zn‐ and Mn‐SOD, and human gingival fibroblast (HGF) SOD activities were examined with the determination of the inhibitory activity of the production of 2‐(4‐Iodophenyl)‐3‐(4‐nitrophenyl)‐5‐(2,4‐disulfophenyl)‐2H‐tetrazolium formazan. Western blot analysis was employed to determine the effect of hydrogen sulfide on SOD molecules. Oxidative damage was determined with comet, caspase III and other assays.

Results and discussion  The activity of Cu,Zn‐SOD (0.01 U ml−1) was found to decrease by 83% when exposed to 52 ng/10 ml of hydrogen sulfide for 60 min (P < 0.0001 by ANOVA and P < 0.001 by Tukey's multiple comparison test) and that of HGF‐SOD decreased by 46% (P < 0.0001 by ANOVA and P < 0.001 by Tukey's multiple comparison test). The inhibition of SOD by H2S was both time‐ and concentration‐dependent. Following exposure to VSC, SOD activity resumed after incubation in air. The results suggested that the inhibition might be reversible. VSC might cleave the disulfide bonds and might produce monomeric SOD resulting in reversible inhibition. However, Western blot analysis has not demonstrated monomeric SOD. Comet assay and other examination demonstrated that VSC caused oxidative damage and apoptosis.

Conclusion  SOD is the body's major defence against oxidative damage. Cu,Zn‐ and Mn‐SOD, and human gingival fibroblast (HGF) SOD activities were strongly inhibited by hydrogen sulfide. The inhibition of SOD resulted in oxidative damage and apoptosis.
O21  Malodour in denture wearers
Authors: Verran J
Published: March 2005

A significant proportion of the adult population wear complete or partial dentures, a proportion increasing with age. Denture plaque has not been studied to the same extent as dental plaque, and although there are many similarities in microbial composition, there are some significant differences. Plaque on denture fitting surfaces, particularly of the upper denture, is associated with denture‐associated stomatitis, with the aetiological agent generally acknowledged as the yeast Candida albicans. In addition, poor denture hygiene and a more acidogenic denture plaque appear to be factors contributing to the condition. Anaerobic microorganisms, although present in denture plaque, have been specifically investigated rarely. Teeth adjacent to partial dentures are also more susceptible to caries and periodontal diseases, perhaps due to an increased plaque buildup at the prosthesis/tooth interface. Dentures are fabricated from polymethylmethacrylate, using casts constructed from impressions taken in the mouth. The denture‐fitting surface is not smooth (although the lingual/labial surfaces are polished) hence plaque accumulates more readily at the relatively stagnant sites. Over time, the epithelial surfaces in the edentulous mouth alter in shape, and dentures may fit less well. Soft liners, or more temporary tissue conditioners are applied to the prosthesis to improve comfort and fit. These materials, are more porous, and may thus entrap and accumulate more plaque biofilm. Little work has been done on malodour associated with denture wearers. There may be a number of reasons for this:

(i) the population is deemed to be one which is less cosmetically aware, less likely to invest in products to enhance aesthetics. As the global population ages, and lifespan extends along with enhanced finance, leisure time and health status in selected developed countries, this presumption is perhaps inappropriate.

(ii) The nature of malodour in denture wearers is ill defined. The wide age and health range presented by denture wearers poses problems in terms of defining the target populations and specific conditions.

(iii) The origin of malodour in denture wearers – and indeed in the elderly in general – is varied: underlying serious illness (malignancy), chronic illness, ulcers, increased medication etc. are all likely to affect breath odour – ammonia, ketones etc.

(iv) The increased likelihood of the presence of Candida spp. in the mouth may contribute ‘yeasty’ odours.

(v) Poor denture hygiene, accumulation of calculus on prostheses, deterioration and colonization of soft liners will cause significant increases in plaque quantity. Products of deterioration of inert materials in the mouth may also contribute to odour.

This presentation will review current status in the area, suggest possible causes of malodour in denture wearers, and consider the need for further work.
O23  Predicting bad breath in the non‐complaining population
Authors: Knaan T , Cohen D , Rosenberg M
Published: March 2005

Relatively few studies have addressed the prevalence and attributes of oral malodor among subjects who do not complain of bad breath. In the present investigation, 88 Israeli adults (mean age 37 ± 9 years) undergoing routine medical checkups, were asked to fill out a questionnaire including 38 questions on general and oral health, dietary habits, and their opinions regarding their own oral malodor levels. Oral malodor assessments included whole mouth odor judge scores on a 0–5 malodor intensity scale, as well as volatile sulfide levels (Halimeter®, Interscan Corp.), and salivary β‐galactosidase (OK to Kiss, InnoScent Ltd.). Based on an odor judge cutoff score of 2, the prevalence of bad breath was found to be 29.8 ± 9.6%. Odor judge scores were significantly correlated with both Halimeter® (r = 0.55, P < 0.01; Pearson) and OK to Kiss (r = 0.59, P < 0.01; Spearman). Dichotomous analysis of odor judge scores, as compared with detection of salivary β‐galactosidase (OK to Kiss) yielded sensitivity, specificity and accuracy of 89, 75 and 79%, respectively. Among the questionnaire results, 10 responses were significantly associated with odor judge scores (P < 0.05, unpaired t‐test). When the 10 responses were factored into linear multiple regression analysis to account for odor judge scores, a multiple R of 0.846 was obtained. The results suggest that (i) the prevalence of bad breath in the general population is at least 20%; (ii) the OK to Kiss is a valid test for measuring the presence of oral malodor; and (iii) a simple questionnaire can be used to determine the degree of oral malodor among subjects without a complaint of bad breath.
O3  Effects of training on experience and non‐experience sensory odor judges
Authors: Nachnani S , Majerus G , Lenton P
Published: March 2005

In oral malodor research, sensory odor judging is considered the gold standard to evaluate and rate breath odor quality and intensity. Although training and calibration of sensory odor judges has been well documented in other scientific disciplines (foods/beverages, air/water quality, personal care products), little data have been published on training judges for bad breath assessment.

Objective  The purpose of this pilot study was to evaluate the training process, with experienced and novice odor judges, for rating both pleasant and unpleasant odorants.

Methods  Six oral malodor sensory judges four with prior experience and two novices were given verbal information on the oral malodor intensity scale (0‐5) and were given the opportunity to sniff a reference sample of n‐butanol, that had been declared to have a level 3 intensity. Subjects then independently assessed 20 odorant samples for odor intensity (pretest). Four unpleasant and two pleasant odorants, in a variety of intensity levels, and a water samplewere included. Subjects then participated in a training program based on the American Society for Testing and Materials (ASTM) standards. Investigators assigned each odorant sample a ‘true’ intensity score. Subjects’ intensity scores were then analyzed as the absolute difference from the ‘true’ intensity. This dependant variable was analyzed using repeated measures ANOVA.

Results  Training significantly (P = 0.02) reduced (improved) odor judge error levels, irrespective of previous experience. When comparing improvement between experienced and novice odor judges, there was no significant (P = 0.99) difference in the size of deviations from the ‘true’ scores (errors) between experienced (0.948) and novice (0.950) judges. There was also no difference (P = 0.94) in improvement in error levels from pre‐ to post‐test for experienced (pre = 1.13 and post = 0.76) or novice (pre = 1.13 and post = 0.78) judges. There was consistent improvement from pre‐ to post‐test for all odorants (P = 0.02; pre = 1.10; post = 0.75) except for dimethylsulfide, which became worse (P = 0.01; pre = 0.97; post = 1.58). When comparing the unpleasant vs pleasant odorants, there was a significant (P = 0.006) difference in error levels (unpleasant 1.09; pleasant 0.70). After removing the water blank scores from the pleasant odorant category the difference was no longer significant (P = 0.26).

Conclusions  A specific training program for odor judges improved subjects’ ability to assess odor intensity irrespective of previous experience. This type of training is recommended prior to conducting oral malodor‐related clinical research trials.
P12  Halitometry in patients with chronic caseous tonsilitis prior to CO2 laser treatment
Authors: Dal Rio AC , Nicola EM
Published: March 2005

Objective  Halitosis is a very common complaint at the ENT clinics. The aim of this study is to assess a population with chronic caseous tonsilitis (CCT) and complaint of halitosis prior to criptolisis with CO2 laser treatment.

Methods  Thirty patients were selected for CO2 laser criptolisis. All patients underwent anamnesis, physical examination and halitometry prior to laser treatment. Halitometry technique followed the HalimeterInterscanTM manufacturer's instructions. Results <150 ppb of Volatile Sulphidric Compounds (VSC) were considered normal.

Results  Thirty patients, nine male (30%) and 21 female (70%), average age 27.7 years (±10.4) underwent halitometry. The patients were divided into two groups: Group A – abnormal halitometry (>150 ppb) – five patients (16.66%); Group B – normal halitometry (<150 ppb) – 25 patients (83.33%). Group A results: one male, four female, average age 25.2 (±5.6). Halitometry was 315.8 ppb (±164), three patients had caseum at examination (60%). Group B results: eight male, 17 female, average age 28.7 (±11.2). Halitometry was 47.9 ppb (±18.6), three patients had caseum at examination (12%).

Discussion  Halitosis is a very common complaint among patients with CCT. Only 16% of the patients with CCT and complaint of oral malodor had abnormal halitometry. Nevertheless this population had a high incidence of tonsillary caseum (60%) comparing to a normal halitometry population (12%).

Conclusions  Halitometry of VSC is useful to detect halitosis in patients with CCT. The presence of caseum at the examination is a predictor factor of abnormal halitometry. Further studies must be done to assess how CO2 laser criptolisis could benefit this population.
P22  Clinical efficacy of a triclosan/copolymer/NaF dentifrice and a commercially available breath‐freshening dentifrice on hydrogen sulfide‐forming bacteria
Authors: Vazquez J , Pilch S , Williams M , Cummins D
Published: March 2005

Objective  The objective of this double blind clinical study was to compare the 4‐h and overnight effects of a triclosan/copolymer/fluoride (TCF) dentifrice and a commercially available breath freshening (CBF) dentifrice containing fluoride for their ability to control H2S‐forming bacteria.

Methods  Following a one‐week washout period of brushing with a regular fluoride dentifrice, subjects reported to the clinical site without performing oral hygiene, eating or drinking in preparation for baseline saliva sampling. After providing a baseline saliva sample, subjects were randomly assigned a test dentifrice and instructed to brush their teeth for one minute, twice a day for one week. On the morning of the 8th day, subjects returned to the test site having refrained from oral hygiene, eating and drinking for overnight sampling. Subjects then brushed for 1 min with the assigned dentifrice, and returned for 2‐ and 4‐h postbrushing evaluations. Following a second one‐week washout, subjects repeated the same regimen, but now using the other dentifrice. Oral micro‐flora samples were collected by subjects rinsing with 10 ml of sterile water for 10 s. Each collected sample was serially diluted and plated in duplicate onto lead acetate agar. After incubating for 72 h, dark colonies were counted, expressed as log colony‐forming units ml−1, and reductions from baseline were calculated.

Results  Compared to baseline, the TCF dentifrice reduced H2S‐forming bacteria 0.82, 0.80 and 0.22 log units at the 2‐, 4‐ and 12‐h time points compared to 0.60, 0.43 and 0.07 log units for the CBF dentifrice. The TCF dentifrice was statistically significantly better (P < 0.05) than the CBF dentifrice at 4 h and overnight after brushing the teeth.

Conclusion  These results support data obtained in organoleptic and gas chromatography studies and strongly suggest that the TCF dentifrice is effective in controlling bacteria implicated in the formation of bad breath.
P24  Comparison of sampling bags used for measuring breath odor
Authors: Hayashida A , Hoshi K , Sato Y , Ito J , Arai T , Imai S , Hanada N , Uematsu H
Published: March 2005

The use of sampling bags to collect breath odor has not been well established. The aim of this study was to compare and judge the quality and performance of three commercially available sampling bags. An aluminized polyethylene bag (Aluminum Bag, Tokyo Deodorant Inc., Japan), the Tedlar® bag (Tedlar® Bag, Tokyo Deodorant Inc.), and a polyester bag (Flek‐Sampler® Nioibukuro; Omi Odorair Service Co. Ltd., Japan) were assessed. A GC instrument (GC14‐B, Shimadzu, Japan) equipped with a flame photometric detection system were used to measure the concentrations of volatile sulfur compounds (VSC: hydrogen sulfide, methyl mercaptan, and dimethyl sulfide) released from the sampling bags over time. An electronic nose (e‐nose) (Odor Discrimination Analyzer FF‐1, Shimadzu, Japan) was used to assess the characteristics of the gas eluted from the inner surfaces of the bags. The GC results showed that the Tedlar® bag had the highest performance, with 73% of the VSC concentration lasting for up to 4 days. The disadvantage of this bag, however, is that the Tedlar® bag itself has an odor that disturbs the e‐nose's response and organoleptic evaluation. The polyester bags were only able to hold hydrogen sulfide for 2 h. The e‐nose's responses were strongly associated with changes in humidity within the polyester bag. The humidity was more stable within the aluminized polyethylene bag, which was able to sustain 94% of the VSC concentration for up to 24 h. In conclusion, Tedlar® bags are beneficial for GC usage. Aluminum coated polyester bags are beneficial for GC measurements, e‐nose measurements, and organoleptic judgements. Polyester bags have poor hold of VSC, but the low cost suits required disposability for the measurements of individual patients. Thus, breath odor sampling bags should be selected based on the specificity of the measuring instrument.
P32  Saliva incubation as replacement for intra‐oral malodour evaluation
Authors: Quirynen M , Zhao H , Soers C , Pauwels M , Van Steenberghe D
Published: March 2005

Background  Breath odor is scored by different techniques, each with its own shortcomings. Organoleptic ratings are uncomfortable for the patient, subjective, influenced by external parameters including food and cosmetics, and lack of international calibration. An intra‐oral VSC rating (Halimeter) or gas chromatography can overcome the embarrassing situation for the patient, but not every clinician has this equipment. This project evaluated the reliability of saliva incubation as an indirect, in vitro, test for bad breath.

Methods  In a double‐blind, randomized, long‐term, parallel study 45 moderate periodontitis patients that received a ‘one‐stage, full‐mouth’ disinfection, oral hygiene instruction (including tongue scraping) and antiseptics. The intra‐oral VSC ratings (at baseline, and at 3 and 6 months) were compared to in vitro VSC recordings of the headspace air from saliva (0.5 ml, 37°C, 1 and 2 h, anaerobic chamber). The latter recordings were further correlated to the number of CFU in the saliva. At the same time the headspace also received an organoleptic rating.

Results  Even though the VSC values remained within a narrow range (90% observation 10–200), a strong correlation was found between the intra‐oral VSC ratings and the 1 h (r = 0.48, P < 0.0001) and 2 h (r = 0.43, P < 0.0001) VSC production of saliva. The VSC values of incubated saliva correlated strongly (r = 0.71) with the CFU for anaerobic species in the saliva. The VSC values and organoleptic ratings of the incubated saliva also correlated strongly (r = 0.64 after 1 h and 0.73 after 2 h incubation).

Conclusions  Saliva incubation can be used as an indirect way to score bad breath. Due to its simplicity it can be useful in longitudinal studies as alternative for direct organoleptic recordings.
P33  In vitro perfusion biofilm model for the growth of oral microbes associated with oral malodour
Authors: Spencer P , Greenman J , Mckenzie C , Flanagan A
Published: March 2005

Objectives  Oral malodour is mainly due to the generation of volatile sulphur compounds (VSC) by oral anaerobes present in the tongue biofilm. The aim of this study was to evaluate the use of a biofilm system to model the ecology and VSC physiology of tongue biofilm microcosms. Of particular interest was the use of the model to maintain a high diversity of bacterial groups and study their response to environmental changes including exposure to VSC substrates and inhibitors.

Methods  Biofilms were grown using a Sorbarod perfusion model modified by supply of anaerobic gas to grow oral anaerobes. Sorbarods were inoculated using tongue scrape suspension containing 3 × 108 cfu ml−1 and pre‐incubated anaerobically for 24 h at 37°C to promote cell adhesion. After 24 h, the biofilm system was perfused at 12 ml h−1 with BHI (0.74 g L−1) supplemented with haemin, cysteine and/or DTT. Biofilms and eluates (released cells) were sampled up to 96 h and numbers of broad bacterial groups enumerated by selective media. VSC production was measured using a HalimeterTM.

Results  Repeated analysis of biofilms showed that a quasi‐steady state was achieved between 48 and 96 h. The mean specific growth rate was 0.018 h−1. Ecological analysis showed all broad groups were maintained at a constant proportion reflecting the original inoculum for both biofilms and eluates. VSC specific activity was upregulated when biofilms were perfused with appropriate VSC‐substrates (cysteine, glutathione and methionine). In situ exposure of the biofilms to pulses of putative inhibitors (Zn, H2O2 and chlorhexidine) at a range of concentrations typically used in vivo gave dose‐dependent inhibition of VSC production (for Zn and H2O2) and reduced viable numbers by one to two log‐fold (H2O2 and chlorhexidine).

Conclusions  The modified Sorbarod perfusion model is suitable for maintaining high diversity biofilms representative of the tongue flora in terms of both ecological behaviour and response towards VSC substrates and inhibitors.
P37  Differences in score and inter examiner variation between four organoleptic methods
Authors: Jensdottir T , Nauntofte B , Rasch A , Dynesen AW , Lykkeaa JS , Bardow A
Published: March 2005

Objective  Organoleptic measurements are important tools for measuring halitosis. Many different methods have been applied, but an internationally recognized standardized method has not yet been agreed on. We hypothesized that four various organoleptic methods: (A) the open mouth method, (B) the counting method, (C) the ‘HA‐HA‐HA’ method (determining breath while the subject says HA‐HA‐HA), and (D) the glass straw method, may produce different scores and inter examiner variations. Thus the aim of this study was to compare the scores and inter examiner variations obtained by these four methods.

Methods  Five trained (UWE Bristol) odour judges (OJs) assessed the breath of 20 test persons (17–71 years) by the methods A to D (see above), in a randomised and blinded set up. The 0–5 organoleptic scale by Rosenberg et al. (1991) was used for determining the intensity of oral malodour. OJs were allowed to score in fractions of 0.25 score. Inter examiner variation was calculated as the average percentage deviation for the scores of each OJ (computed from the mean score of the five OJs).

Results  The mean organoleptic score of the 20 subjects differed significantly depending on the method applied (P < 0.001). Method (A) produced a score of 1.20 ± 0.88, (B) 1.69 ± 0.83, (C) 1.80 ± 0.89, and (D) a score of 2.11 ± 0.92. Further a significant difference was obtained for the inter examiner variation between the four methods (P < 0.001). The inter examiner variation for method (A) was 55%, for (B) 30%, for (C) 31%, and for (D) 26%. Finally a significant correlation was obtained between the organoleptic score and the inter examiner variation (rs = −0.70, P < 0.001) becoming lower with higher scores.

Conclusion  Due to the higher mean scores and the lower inter examiner variation the glass straw method may be preferable for organoleptic research studies of halitosis.
P43  Effectiveness of a mechanic‐chemical method in reducing malodor of dentures
Authors: Sazvar SMR , Dashti MH , Afshan BK
Published: March 2005

Objective of investigation  To assess effectiveness of a mechanic‐chemical denture cleansing to reduce malodor in denture wearers in comparison with a brushing only method.

Methods  Twenty‐nine denture wearers between 50 and 60 years old, 6 months after denture delivery were trained to clean their dentures with denture brush and soak in normal saline at nights for 1 month. The malodor of dentures was detected with a bad breath detector (VSC monitor: Tanita, Japan). In the following month the subjects were trained to clean with a denture brush but additionally soak in antiseptic mouthwash (Listerine, USA) each night and soak in 5% sodium hypochlorite twice a week for 5 min. At the end of 1 month the malodor of dentures was again assessed using the VSC monitor.

Results and discussion  For denture brush alone all cases showed severe malodor VSC levels. Following the mechanic‐chemical cleansing, 20 cases gave moderate and nine cases gave mild malodor VSC levels. Statistical analysis with Wilcoxon test determined the mechanic‐chemical method to have been significantly effective (P‐value <0.05). The results show that for reducing malodor of dentures, denture brush alone is insufficient and use of antiseptic materials are necessary. Some studies have stated that allergic reactions to sodium hypochlorite are possible and in addition denture cleansing may be difficult for disabled or elderly patients. Therefore, future studies should focus on non‐allergic disinfectants and/or simpler/easier methods (recommended protocols) to carry out effective disinfection.

Conclusion  The mentioned mechanic‐chemical method proved to be effective at reducing malodor of dentures whilst brushing alone was insufficient.
P44  Management of volatile sulphur compounds with ozone
Authors: Holmes J
Published: March 2005

Volatile sulphur compounds (VSCs) are responsible for oral malodour (bad breath). There are many otc products for people for use, based on an oxidative reaction system. This paper examines the effect of ozone on VSCs.

Objective  To test the efficacy of Ozone (O3) dissolved in water on VSCs and the management of bad breath in a small pilot study in a general dental practice environment, test the Halimeter, and test a new bad breath Index, the Ks Index.

Method  Twenty subjects were recruited into this study. After olfactory assessment, they were assigned to a Ks Index (The Kissability Index) and measured with the Halimeter (Interscan Corp, USA) after calibration, to establish their base‐line VSCs. Each subject gargled with ozonated water for 30 s, and were re‐assessed with the Halimeter. This was repeated after 5‐, 30‐ and 60‐min intervals. Ozone (O3) was bubbled under pressure into 1 l of cooled, distilled water at a concentration of 2100 ppm for 1 min for each subject.

Results  After just 1 min of gargling and mouth rinsing with 100 ml ozonated water, there was an average VSC reduction of 42.5% from the pretreatment baseline value. Five minutes after treatment, the VSCs rose an average of 14.2%; after 30 min, a further 18.9%, and after 60 min, the VSC values had risen by a further 24.6%. Ozone is a powerful oxidant, and in gaseous form, is used to reverse caries (1). When dissolved in water (maximum 5% volume in distilled, cooled and pressurised water) ozone is safe, and has been extensively used in reducing cfu's in dental water lines (2). Studies in Russia (3) have shown ozone to be an effective oral hygiene adjunct. This study showed that low concentrations of ozonized water is cheap and easy to make. It is a very effective product to reduce VSC's, and further research is proposed in this area.

Conclusion  Ozone dissolved in water may offer a cheap alternative to the more expensive and less effective commercial mouth rinses to combat bad breath. However it is unstable (half‐life of about 2–3 h if kept cold) and needs to be manufactured when required. It may have a greater role in the control of oral hygiene or as a presurgical mouth rinse.
P45  Microbiological culture analysis of the tongue microflora in subjects with and without halitosis
Authors: Donaldson AC , McKenzie D , Flanagan AJ , Riggio MP
Published: March 2005

Objective  Determination of the microflora present on the tongue dorsum of subjects with and without halitosis using conventional microbiological culture methods.

Methods  Twenty‐one halitosis and 20 control patients were recruited using a strict clinical protocol. Samples were collected from the posterior dorsum of the tongue using a sterile brush. Each sample was vortex mixed for 30 s and serial 10‐fold dilutions to 10−7 were carried out. Samples were plated onto fastidious anaerobe agar (FAA) and FAA enriched with vancomycin. These were incubated under anaerobic conditions for 10 days at 37°C. Strict anaerobes were identified by metronidazole sensitivity and bacteria were identified to genus level by a combination of colony morphology, Gram staining and biochemical and enzymatic tests (rapid ID 32 A).

Results  The predominant species in test and control groups were Veillonella and Prevotella. Greater species diversity was found in the halitosis samples compared to controls. The halitosis samples contained a larger number of unidentifiable gram‐negative rods, gram positive rods and gram negative coccobacilli.

Conclusions  There was no obvious association between halitosis and any specific bacterial genus. The increased species diversity found in halitosis samples suggests that halitosis may be the result of complex interactions between several bacterial species. The role of uncultivable bacteria may also be important in contributing to this process.
P46  Stable storage of chlorine dioxide mouthrinse solutions
Authors: Richter JL , Kross R
Published: March 2005

Chlorine dioxide (ClO2) is a highly effective yet non‐toxic malodor counteractant and germicide that is listed as an ingredient in many mouthrinses. It is a water‐soluble gas whose purported chemical instability and permeability through common storage containers has resulted in its inability to be provided as a shelf‐stable, marketable solution of significant concentration. Thus ClO2 has had to be generated in situ, or shortly before use, which has limited its utility. The object of the present investigation was to evaluate ClO2 concentrations over time in aqueous, near neutral pH, ClO2‐ClO2−(1:1–1:14) solutions (32–40 ppm ClO2) prepared according to the method of Richter in containers made from a variety of materials under ambient, accelerated storage and other conditions. [ClO2] was measured with standard spectrophotometric technique. All containers tested were standard 16 oz. bottles. The materials tested were glass of various colors and opacities, polyvinyl chloride (PVC), high‐density polyethylene (HDPE), fluorinated HDPE, high‐density terephthalate (PETE) of various colors and fluoridated polyolefins. We discovered that certain materials, such as glass, fluoridated HDPE, clear and white PETE and fluorinated polyolefins can maintain relatively constant levels of ClO2 in pre‐prepared solutions and in some cases for periods of up to several years under ambient and normal shipping conditions. In one series of studies, the mean loss of ClO2 per day from solutions prepared to approximately 35 ppm was 0.8 ppm (s.d. = 2.9) (2.2%) for HDPE (32 days); 0.8 ppm (s.d. = 2.2)(2.16%) for PVC (30 days); 0.4 ppm (s.d. = 0.71)(1.20%) for fluoridated HDPE (45 days); 0.02 ppm (s.d. = 0.63) (0.045%) for PETE (45 days) and 0.14 ppm gain (s.d. 0.54)(0.31%) for clear glass (31 days). The s.d.s reported here are skewed high because they assume a linear loss of ClO2 over time when in fact the actual measured loss (or gain) was in all cases nearly perfectly parabolic. In another study, one supplier's white opaque PETE actually showed a 6.2% overall gain in 252 days of storage. These results dispel the popular notion that ClO2 always decomposes so rapidly that fresh solutions must be made up frequently to maintain effective ClO2 concentrations. ClO2 production from the reservoir of ClO2− in these solutions is apparently sufficient to equal or exceed losses of ClO2 from decomposition, diffusion through the container wall, possible reaction with the container material and escape during sampling for some of the materials tested. Previously observed losses of [ClO2] from ClO2‐ClO2− solutions were apparently due primarily to diffusion out of the containers rather than from decomposition within the containers. This achievement now allows for the broad distribution of pre‐prepared ClO2 solutions for a wide range of oral care and other deodorant and germicidal applications.