Ruthenium(II)-Bipyridine/NanoC3 N4 Hybrids: Tunable Photochemical Properties by Using Exchangeable Alkali Metal Cations.

A series of nanoporous carbon nitrides that contained a range of alkali metal cations (M@nanoC3 N4 : M=Li+ , Na+ , K+ , Rb+ , and Cs+ ) have been successfully synthesized from as-synthesized g-C3 N4 by delamination with concentrated sulfuric acid, followed by neutralization with aqueous solutions of the corresponding alkali metal hydroxides. Tris(2,2'-bipyridine)ruthenium(II) complexes, [Ru(bpy)3 ]2+ , were grafted onto the carbon nitrides in an effort to explore the physicochemical properties of the deposited [Ru(bpy)3 ]2+ , as well as its photocatalytic activity in the aerobic photooxidation of phenylboronic acid and H2 production from aqueous media in the presence of a Pt co-catalyst under visible-light irradiation. Highly porous nanoC3 N4 could significantly enhance photocatalytic activity, because of its high surface area, owing to its unique porous structure. More interestingly, the photoluminescence intensities of [Ru(bpy)3 ]2+ complexes that were associated with M@nanoC3 N4 increased in the presence of lighter alkali metal cations, which correlated with increased photocatalytic activities for both reactions. This study demonstrates that M@nanoC3 N4 are fascinating supports, in which the local environment of an immobilized metal complex can be precisely controlled by varying the alkali metal cation from Li+ to Cs+ .

Nickel-supported carbon nitride photocatalyst combined with organic dye for visible-light-driven hydrogen evolution from water.

A noble-metal-free photocatalytic H2 production system consisting of a Ni-based catalyst, visible-light-responsive organic dye, and graphitic carbon nitride (g-C3N4) as a support has been developed. Characterization by means of XAFS revealed that the deposition of a trinuclear Ni precursor complex, Ni(NiL2)2Cl2 (L = ß-mercaptoethylamine), on the g-C3N4 affords a monomeric Ni(ii) species involving ß-mercaptoethylamine and aqua ligands in an octahedral coordination geometry. Such a Ni species acts as a hydrogen production site from an aqueous solution without an electron relay reagent by combining with thiazole orange (TO) as a photosensitizer. The emission of the attached TO at around 550 nm decreases with increasing loading amount of Ni catalyst, suggesting electron transfer from TO to the Ni catalyst via the g-C3N4 support. Leaching and agglomeration of the active Ni catalyst and TO are not observed during the photocatalytic reaction. Moreover, the use of highly porous carbon nitride (nanoporous carbon nitride; nanoC3N4) is proven to significantly enhance the photocatalytic activity because of the high surface area due to the unique porous structure as well as high absorption and emission properties of TO associated with nanoC3N4.

Lactobacillus salivarius WB21--containing tablets for the treatment of oral malodor: a double-blind, randomized, placebo-controlled crossover trial.

OBJECTIVE: This study evaluated the effect of probiotic intervention using lactobacilli on oral malodor. STUDY DESIGN: We conducted a 14-day, double-blind, placebo-controlled, randomized crossover trial of tablets containing Lactobacillus salivarius WB21 (2.0 × 10(9) colony-forming units per day) or placebo taken orally by patients with oral malodor. RESULTS: Organoleptic test scores significantly decreased in both the probiotic and placebo periods compared with the respective baseline scores (P < .001 and P = .002), and no difference was detected between periods. In contrast, the concentration of volatile sulfur compounds (VSCs) (P = .019) and the average probing pocket depth (P = .001) decreased significantly in the probiotic period compared with the placebo period. Bacterial quantitative analysis found significantly lower levels of ubiquitous bacteria (P = .003) and Fusobacterium nucleatum (P = .020) in the probiotic period. CONCLUSIONS: These results indicated that daily oral consumption of tablets containing probiotic lactobacilli could help to control oral malodor and malodor-related factors.

Effect of S-PRG Eluate on Biofilm Formation and Enzyme Activity of Oral Bacteria.

Recently, the antibacterial activity of a composite resin containing prereacted glass ionomer (S-PRG) filler was revealed. We examined the effect of an S-PRG eluate on various biologic activities of Streptococcus mutans and Porphyromonas gingivalis. Adherence ability of S. mutans was evaluated by microtiter plate assay; protease and gelatinase activities of P. gingivalis were examined by synthetic substrate hydrolysis and gelatin film spot assay, respectively. Coaggregation of P. gingivalis with Fusobacterium nucleatum was also examined. S-PRG eluate was found to suppress streptococcal adherence. S-PRG eluate inhibited the protease and gelatinase activities of P. gingivalis and the coaggregation between P. gingivalis and F. nucleatum. These results indicate that S-PRG eluate suppresses streptococcal adherence and inhibits the protease and coaggregation activities of P. gingivalis. These findings may prompt research into novel strategies for preventing caries and periodontitis.

Effects of oil drops containing Lactobacillus salivarius WB21 on periodontal health and oral microbiota producing volatile sulfur compounds.

The objective of this paper is to evaluate the effects of oil drops containing Lactobacillus salivarius WB21 on periodontal health and oral microbiota producing volatile sulfur compounds (VSCs). For this study, 42 subjects were randomly assigned to receive oil samples containing L. salivarius WB21 or a placebo for two weeks. Oral assessment and saliva collection were performed on days 1 and 15. Bacterial analysis was performed using the real-time polymerase chain reaction and terminal restriction fragment length polymorphism (T-RFLP). In both the experimental and placebo groups, the average probing depth, number of periodontal pockets, and the percentage of bleeding on probing (BOP) decreased while stimulated salivary flow increased on day 15. BOP was reduced in the experimental group compared with the placebo group (P = 0.010). In the experimental group, total bacterial numbers decreased, and the number of L. salivarius increased. The number of Prevotella intermedia, which is correlated with hydrogen sulfide concentration in mouth air, increased in the placebo group and did not change in the experimental group. T-RFLP analysis found that the peak area proportions representing Porphyromonas gingivalis, P. intermedia, Tannerella forsythensis, and Fusobacterium nucleatum decreased in the experimental group, although there was no significant change in the bacterial composition. Thus we observed oil drops containing L. salivarius WB21 improved BOP and inhibited the reproduction of total and VSC-producing periodontopathic bacteria compared with the placebo group, but also showed the limit of its efficacy in controlling VSCs producing and periodontal pathogens.

Enterococcus faecium WB2000 Inhibits Biofilm Formation by Oral Cariogenic Streptococci.

This study investigated the inhibitory effect of probiotic Enterococcus faecium WB2000 on biofilm formation by cariogenic streptococci. The ability of E. faecium WB2000 and JCM5804 and Enterococcus faecalis JCM5803 to inhibit biofilm formation by seven laboratory oral streptococcal strains and 13 clinical mutans streptococcal strains was assayed. The Enterococcal strains inhibited biofilm formation in dual cultures with the mutans streptococcal strains Streptococcus mutans Xc and Streptococcus sobrinus JCM5176 (P < 0.05), but not with the noncariogenic streptococcal strains. Enterococcus faecium WB2000 inhibited biofilm formation by 90.0% (9/10) of the clinical S. mutans strains and 100% (3/3) of the clinical S. sobrinus strains. After culturing, the pH did not differ between single and dual cultures. The viable counts of floating mutans streptococci were lower in dual cultures with E. faecium WB2000 than in single cultures. Enterococcus faecium WB2000 acted as a probiotic bacterial inhibitor of cariogenic streptococcal biofilm formation.

Association between oral malodour and psychological characteristics in subjects with neurotic tendencies complaining of halitosis.

OBJECTIVE: To assess the psychosomatically subjective symptoms of subjects with neurotic tendencies complaining of halitosis. DESIGN: Breath malodour was measured in 368 patients using organoleptic test and gas chromatography. Neurotic tendency and subjective symptoms were assessed using the Cornell Medical Index (CMI). RESULTS: Of the 79 subjects who met the criteria for neurotic tendencies according to CMI scores, 58 (73.4%) had oral malodour, whereas 21 (26.6%) did not. Coated tongue, periodontal pocket, and daily drinking were significantly more common in subjects with oral malodour. On the CMI questionnaire, subjects with no oral malodour more frequently responded 'yes' to questions about fatigue and psychological problems in their families. Additionally, many answered that they had perceived their own bad breath. CONCLUSIONS: Difficulties experienced by subjects with neurotic tendencies and oral malodour may manifest primarily in oral conditions, whereas those experienced by individuals with neurotic tendencies and no oral malodour may manifest primarily in psychosomatic symptoms.

Effects of probiotic Lactobacillus salivarius WB21 on halitosis and oral health: an open-label pilot trial.

OBJECTIVE: The objective of this study was to evaluate whether oral administration of lactobacilli alters the degree of halitosis and clinical conditions associated with halitosis. STUDY DESIGN: Twenty patients with genuine halitosis were given 2.0 x 10(9)Lactobacillus salivarius WB21 and xylitol in tablet form daily. Oral malodor and clinical parameters were evaluated at the same time of day for each patient after 2 and 4 weeks. RESULTS: All 20 patients were positive for L. salivarius DNA in their saliva at 2 weeks, although 12 patients were negative for this organism at baseline. Oral malodor parameters significantly decreased at 2 weeks in the subjects with physiologic halitosis. The scores of an organoleptic test and bleeding on probing significantly decreased at 4 weeks in the subjects with oral pathologic halitosis. CONCLUSIONS: Oral administration of probiotic lactobacilli primarily improved physiologic halitosis and also showed beneficial effects on bleeding on probing from the periodontal pocket.

The relationship between alcohol consumption and oral malodour.

OBJECTIVE: To analyse the relationship between alcohol consumption and oral malodour. SUBJECTS: 235 individuals, aged 46.5 +/- 15.3 years (mean +/- SD), who complained of oral malodour. METHODS: An organoleptic test (OLT) was used to estimate the degree of oral malodour, gas chromatography was used to measure volatile sulphur compounds (VSCs), and a questionnaire was used to gather data about the subjects' habits related to alcohol consumption. RESULTS: Of the 55 individuals who consumed alcohol daily, 17 (30.9%) had strong malodour (OLT score, 4), and there were significant differences among the 'daily', 'sometimes', and 'no alcohol' groups (Kruskal-Wallis test, p < 0.01). The daily group also had a higher VSC concentration than the 'sometimes' and 'no alcohol' groups (t-test, p < 0.05), and there was no difference in the VSC concentration among the subjects with strong malodour. Analyses of the relationships between drinking habits and the clinical factors causing oral malodour revealed that daily drinking was positively associated with a probing pocket depth > or = 5 mm (chi2 test, p < 0.01). CONCLUSION: This study found an association between daily alcohol consumption and strong malodour, especially related to periodontal disease.

A Case Report of Tooth Wear Associated with a Patient's Inappropriate Efforts to Reduce Oral Malodor Caused by Endodontic Lesion.

Here, we report a case of severe tooth wear associated with a patient's inappropriate efforts to reduce oral malodor. A 72-year-old male patient visited our breath clinic complaining of strong breath odor. Former dentists had performed periodontal treatments including scaling and root planing, but his oral malodor did not decrease. His own subsequent breath odor-reducing efforts included daily use of lemons and vinegar to reduce or mask the odor, eating and chewing hard foods to clean his teeth, and extensive tooth brushing with a hard-bristled toothbrush. Oral malodor was detected in our breath clinic by several tests, including an organoleptic test, portable sulphide monitor, and gas chromatography. Although patient's oral hygiene and periodontal condition were not poor on presentation, his teeth showed heavy wear and hypersensitiving with an unfitted restoration on tooth 16. Radiographic examination of the tooth did not reveal endodontic lesion, but when the metal crown was removed, severe pus discharge and strong malodor were observed. When this was treated, his breath odor was improved. After dental treatment and oral hygiene instruction, no further tooth wear was observed; he was not concerned about breath odor thereafter.

Detection of Helicobacter pylori DNA in the saliva of patients complaining of halitosis.

Helicobacter pylori infection, which causes peptic ulcers and gastric cancer, is considered a possible cause of halitosis. Recently, the oral cavity was identified as a possible H. pylori reservoir, particularly in the presence of periodontal disease, which is a cause of halitosis. The purpose of this study was to evaluate by PCR the prevalence of oral H. pylori in the saliva of subjects complaining of halitosis. Samples were obtained from 326 non-dyspeptic subjects, comprising 251 subjects with actual malodour and 75 subjects without halitosis. DNA was extracted from the samples, and the presence of H. pylori and periodontopathic bacteria including Porphyromonas gingivalis, Treponema denticola and Prevotella intermedia was examined by PCR. H. pylori was detected in 21 (6.4 %) of 326 samples. The methyl mercaptan concentration and periodontal parameters including tooth mobility, periodontal pocket depth (PPD) and occult blood in the saliva were significantly greater in the H. pylori-positive subjects. Each of the periodontopathic bacteria was also detected at a significantly higher frequency in the H. pylori-positive subjects. Among those patients with a PPD of > or =5 mm and a tongue coating score of < or =2, no difference was observed in oral malodour levels between the H. pylori-positive and -negative subjects. However, the presence of occult blood in the saliva and the prevalence of Prevotella intermedia were significantly greater in the H. pylori-positive subjects. H. pylori was detected in 16 (15.7 %) of 102 subjects with periodontitis, suggesting that progression of periodontal pocket and inflammation may favour colonization by this species and that H. pylori infection may be indirectly associated with oral pathological halitosis following periodontitis.

Relationship between halitosis and psychologic status.

OBJECTIVE: To examine the psychosomatic aspects of patients complaining of halitosis. STUDY DESIGN: Breath malodor in 165 patients was measured using an organoleptic test (OLT), sulfide monitoring, and gas chromatography. Clinical evaluation included oral examination, OLT, and volatile sulfur compound measurement. The psychologic condition of patients was assessed using the Cornell Medical Index (CMI). RESULTS: Every item in the CMI questionnaire was negatively correlated with the OLT scores. Nine of 21 subjects (42.9%) diagnosed with pseudohalitosis and approximately 20% of subjects diagnosed with genuine halitosis were considered to be provisionally neurotic. Subjects with pseudohalitosis reported significantly higher physical scores, but not mental scores, than those with genuine halitosis. Subjects with physiologic halitosis showed significantly higher symptoms of depression than those with oral pathologic halitosis. CONCLUSION: The psychologic condition of patients complaining of halitosis was associated with the actual degree of malodor and the clinical characteristics.