Whereas previous studies have shown correlations between volatile sulphur compounds (VSC) and bad breath levels, it is probable that other compounds found in the oral cavity may contribute to oral malodor. In the present investigation, the possibility that diamines (cadaverine and putrescine) are associated with oral malodor parameters was assessed. Saliva samples from 52 subjects were analyzed for cadaverine and putrescine by HPLC. Oral malodor of whole mouth, tongue, and saliva of the subjects was recorded by an experienced judge on a continuous 10-cm scale; peak and steady-state VSC intraoral levels were measured by the Interscan 1170 sulphide monitor. Log-transformed VSC and diamine levels were compared with odor judge measurements by Pearson analysis and stepwise forward multiple regression. Putrescine scores were not significantly associated with odor judge parameters or with VSC levels (p > 0.1). However, highly significant correlations (p < or = 0.003) were found between cadaverine levels and all three odor judge assessments. In contrast, associations between cadaverine and VSC measurements were non-significant. In an attempt to correlate odor judge results in terms of both VSC and diamines, we carried out stepwise forward multiple regression. Results showed that VSC and cadaverine both factor significantly in explaining each of the odor judge measurements, with multiple r values ranging from 0.545 (p = 0.0002) to 0.604 (p < 0.0001). The results suggest that cadaverine levels are associated with oral malodor, and that this association may be independent of VSC.

We present a novel method for producing complex metallic nanostructures of programmable design. DNA origami templates, modified to have DNA binding sites with a uniquely coded sequence, were adsorbed onto silicon dioxide substrates. Gold nanoparticles functionalized with the cDNA sequence were then attached. These seed nanoparticles were later enlarged, and even fused, by electroless deposition of silver. Using this method, we constructed a variety of metallic structures, including rings, pairs of bars, and H shapes.

Bad breath is a common phenomenon, usually the result of bacterial metabolism in the oral cavity. It is generally accepted that Gram-negative bacteria are responsible for this problem, largely through degradation of proteinaceous substances. In initial experiments, screening of malodorous isolates following outgrowth of samples obtained from saliva, periodontal pockets, and the tongue dorsum yielded enterobacterial isolates. Clinical studies were conducted to examine the prevalence of such bacteria in four different populations: orthodontic patients, malodor clinic patients, complete-denture wearers, and a healthy young population. The prevalence of Enterobacteriaceae in the oral cavities of the denture-wearing population was very high (48.0%) as compared with the other groups: 27.1% in the malodor clinic patients, 16.4% in the normal population, and 13% among orthodontic patients. Isolates of Klebsiella and Enterobacter emitted foul odors in vitro which resembled bad breath, with concomitant production of volatile sulfides and cadaverine, both compounds related to bad breath. When incubated on a sterile denture, enterobacterial isolates produced typical denture foul odor. Isolates exhibited cell-surface hydrophobic properties when tested for adhesion to acryl and aggregation with ammonium sulphate. The results, taken together, suggest that Klebsiella and related Enterobacteriaceae may play a role in denture malodor.

The purpose of the study was to examine the anti‐malodor, anti‐gingivitis, and plaque reducing properties of a 2 phase oil:water mouthrinse compared with a control mouthrinse. Fifty subjects rinsed with one of the two rinses for 30 seconds twice a day over 6 weeks, while continuing their normal oral hygiene habits. Measurements were made at time zero (prior to beginning the rinsing regimen), and ≥ 9 hours following rinsing, at intervals of 1, 3, and 6 weeks. Malodor of whole mouth, as well as tongue dorsum anterior and posterior, was assessed on a 0 to 5 semi‐integer scale by two odor judges. Volatile sulphide compounds (VSC) were determined using a sulphide monitor. Gingival, plaque, and bleeding indices were recorded for Ramfjord teeth. Oral microbial levels were assessed using the oratest. Salivary levels of diamines (putrescine and cadaverine) were analyzed by HPLC. Results were analyzed by 2tailed covariant ANOVA, with the time zero value as covariant. Dramatic improvements were observed in parameters associated with malodor, periodontal health, plaque accumulation, and microbial levels in both groups. As compared to time zero scores, whole mouth odor, tongue dorsum anterior and posterior odors decreased continuously over time, attaining 80%, 79% and 70%, reductions, respectively following 6 weeks, in the 2‐phase mouthrinse group, versus 70%, 77% and 59% for the control group. For whole mouth and tongue dorsum posterior, the reductions observed in the 2‐phase mouthrinse group were significantly greater than those obtained with the control mouthrinse (P = 0.026 and P = 0.025, respectively), suggesting that the 2‐phase mouthrinse is superior to the control mouthrinse in long‐term reduction of oral malodor. For bleeding index, gingival index, oral microbial levels, and VSC, differences between the groups were not significant. Diamine levels were not significantly reduced in either group. The control mouthrinse reduced plaque index more significantly than the 2‐phase mouthrinse (P < 0.005). The results of this randomized clinical trial suggest that the 2‐phase oikwater mouthrinse formulation is superior to the control mouthrinse in long‐term reduction of oral malodor. J Periodontol 1996;67:577–582.

Polycationic polymers have been noted for their effects in promoting cell adhesion to various surfaces, but previous studies have failed to describe a mechanism dealing with this type of adhesion. In the present study, three polycationic polymers (chitosan, poly-L-lysine, and lysozyme) were tested for their effects on microbial hydrophobicity, as determined by adhesion to hydrocarbon and polystyrene. Test strains (Escherichia coli, Candida albicans, and a nonhydrophobic mutant, MR-481, derived from Acinetobacter calcoaceticus RAG-1) were vortexed with hexadecane in the presence of the various polycations, and the extent of adhesion was measured turbidimetricaily. Adhesion of all three test strains rose from near zero values to over 90% in the presence of low concentrations of chitosan (125 to 250 ,ug/ml). Adhesion occurred by adsorption of chitosan directly to the cell surface, since E. coli cells preincubated in the presence of the polymer were highly adherent, whereas hexadecane droplets pretreated with chitosan were subsequently unable to bind untreated cells. Inorganic cations (Na+, Mg2+) inhibited the chitosan-mediated adhesion of E. coli to hexadecane, presumably by interfering with the electrostatic interactions responsible for adsorption of the polymer to the bacterial surface. Chitosan similarly promoted E. coli adhesion to polystyrene at concentrations slightly higher than those which mediated adhesion to hexadecane. Poly-L-lysine also promoted microbial adhesion to hexadecane, although at concentrations somewhat higher than those observed for chitosan. In order to study the effect of the cationic protein lysozyme, adhesion was studied at 0°C (to prevent enzymatic activity), using n-octane as the test hydrocarbon. Adhesion of E. coli increased by 70% in the presence of 80 ,ug of lysozyme per ml. When the negatively charged carboxylate residues on the E. coli cell surface were substituted for positively charged ammonium groups, the resulting cells became highly hydrophobic, even in the absence of polycations. The observed "hydrophobicity" of the microbial cells in the presence of polycations is thus probably due to a loss of surface electronegativity. The data suggest that enhancement of hydrophobicity by polycationic polymers is a general phenomenon.