Laboratory evaluation of extrinsic stain removal by a specially engineered sonic powered toothbrush with unique sensing and control technologies

OBJECTIVE

The purpose of this laboratory study was to evaluate extrinsic stain removal from teeth by a specially engineered sonic powered toothbrush with unique sensing and control technologies, using the Triple Clean and the Sensitive refill brush heads, in comparison to a manual flat-trim toothbrush.

METHODS

Twelve (12) artificially stained bovine teeth were tested with each product. The percentage of stain removed by each product was calculated by taking the ratio of the amount of stain removed by brushing for 800 strokes to the total amount of stain removed by subsequent application of a dental prophylaxis. The stain was quantified by measuring the light reflected by the stained teeth with a spectrophotometer. Data were reported as L*, lightness of the stain, and as W*, a whiteness index comprising the lightness, hue, and chroma of reflected light. Statistical analyses were performed separately for the AL* and AW* scores. Comparisons of the toothbrushes with respect to baseline-adjusted deltaL* and deltaW* scores were performed using an analysis of covariance (ANCOVA). Post-ANCOVA pair-wise comparisons of the study toothbrushes were performed using Tukey's test for multiple comparisons. All statistical tests of hypotheses were two-sided, and employed a minimum level of significance of 0.05.

RESULTS

The percentage of stain removed by the sonic powered toothbrush, using either the Triple Clean brush head or the Sensitive brush head under laboratory test conditions, is superior (p < 0.05) to the percentage of stain removed by the manual flat-trim toothbrush when analyzed for both the deltaL* and deltaW* scores. The mean percentage of stain removed was 62.10 for the power toothbrush with the Triple Clean brush head, 49.01 for the power toothbrush with the Sensitive brush head, and 30.56 for the manual flat-trim toothbrush when calculated using deltaL* scores. The mean percentage of stain removed was 59.89 for the power toothbrush with the Triple Clean brush head, 46.83 for the power toothbrush with the Sensitive brush head, and 29.25 for the manual flat-trim toothbrush when calculated using deltaW* scores.

CONCLUSIONS

This new specially engineered sonic powered toothbrush with unique sensing and control technologies effectively removes extrinsic stains from the surface of teeth under laboratory test conditions with both the Triple Clean and the Sensitive brush heads. The effectiveness of stain removal with either brush head is significantly greater than the effectiveness of stain removal of a manual flat-trim toothbrush under these conditions.

Membrane lipid alkyl chain motional dynamics is conserved in Sarcina ventriculi despite pH-induced adaptative structural modifications including alkyl chain tail to tail coupling

Sarcina ventriculi, an anaerobic Gram-positive bacterium, adapts to increasing temperature, the presence of organic solvents, or the lowering of the pH of its growth medium by joining the tails of membrane lipids from opposite sides of the bilayer, forming transmembrane, bifunctional fatty acid species. Since this is done to offset the increase in membrane mobility caused by these perturbations, it is of interest to determine whether the motional (dynamic) properties of membrane lipid alkyl chains are conserved. In this study, conservation of the motional time scales of the alkyl chains of total membrane lipids from Sarcina ventriculi cells grown at different pH values was demonstrated using proton nuclear magnetic resonance (NMR) spectroscopy. The NMR longitudinal relaxation times (T1) of the protons in the bulk methylene groups were measured for lipids from cells grown at pH 3.0 and 7.0. These measurements indicated that the temperature profile of the T1 relaxation behavior for the methylene protons from these two different preparations was the same. Analysis of the data from T1 measurements indicated that the thermal barrier for relaxation is the same in both lipid systems. This is only true if the pH of the sample on which the measurement is being made is adjusted to the same value as that at which the corresponding cells were cultured. It is clear from this latter observation that the state of protonation of the lipid head groups is a contributor to the overall motional freedom of the membrane lipid components. The correlation times (tau c) of characteristic lipid alkyl chain motion were estimated to be approximately 10(-10) s.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of pH extremes on sporulation and ultrastructure of Sarcina ventriculi

Distinct morphological changes in the ultrastructure of Sarcina ventriculi were observed when cells were grown in medium of constant composition at pH extremes of 3.0 and 8.0. Transmission electron microscopy revealed that at low pH (less than or equal to 3.0) the cells formed regular packets and cell division was uniform. When the pH was increased (to greater than or equal to 7.0), the cells became larger and cell division resulted in irregular cells that varied in shape and size. Sporulation occurred at high pH (i.e., greater than or equal to 8.0). The sporulation cycle followed the conventional sequence of development for refractile endospores, with the appearance of a cortex and multiple wall layers. The spores were resistant to oxygen, lysozyme, or heating at 90 degrees C for 15 min. Spores germinated within the pH range of 4.6 to 7.0.

Physiological adaptations of anaerobic bacteria to low pH: metabolic control of proton motive force in Sarcina ventriculi

Detailed physiological studies were done to compare the influence of environmental pH and fermentation end product formation on metabolism, growth, and proton motive force in Sarcina ventriculi. The kinetics of end product formation during glucose fermentation in unbuffered batch cultures shifted from hydrogen-acetate production to ethanol production as the medium pH dropped from 7.0 to 3.3. At a constant pH of 3.0, the production of acetate ceased when the accumulation of acetate in the medium reached 40 mmol/liter. At a constant pH of 7.0, acetate production continued throughout the entire growth time course. The in vivo hydrogenase activity was much higher in cells grown at pH 7.0 than at pH 3.0. The magnitude of the proton motive force increased in relation to a decrease of the medium pH from 7.5 to 3.0. When the organism was grown at pH 3.0, the cytoplasmic pH was 4.25 and the organism was unable to exclude acetic acid or butyric acid from the cytoplasm. Addition of acetic acid, but not hydrogen or ethanol, inhibited growth and resulted in proton motive force dissipation and the accumulation of acetic acid in the cytoplasm. The results indicate that S. ventriculi is an acidophile that can continue to produce ethanol at low cytoplasmic pH values. Both the ability to shift to ethanol production and the ability to continue to ferment glucose while cytoplasmic pH values are low adapt S. ventriculi for growth at low pH.

Target substances of some antifungal agents in the cell membrane

Copiamycin, an antifungal antibiotic, exhibits antimicrobial activity against a few bacteria in addition to a wide variety of fungi. The methanol extract of Sarcina lutea, one of the most susceptible bacteria, was found to reverse the antimicrobial activity of copiamycin. The reversing activity was associated with the phospholipid fraction of the bacteria. The S. lutea phospholipids also reversed the activities of azalomycin F and miconazole, but not that of clotrimazole. The effects of authentic phospholipids and fatty acids were also investigated. As the antimicrobial activities of copiamycin and azalomycin F were most strongly reversed in the same manner by phospholipids with unsaturated fatty acids and basic hydrophilic groups, the sites on the cell membrane sensitive to both antibiotics are assumed to be identical. On the other hand, the activity of miconazole was affected by different phospholipids from those which affected these two antifungal antibiotics, and the activity of clotrimazole was not affected by any of the phospholipids and fatty acids. It was postulated that the sites on the cell membrane sensitive to miconazole and clotrimazole are different from those sensitive to copiamycin and azalomycin F.

Anti-riboflavin activity of 8N-alkyl analogues of roseoflavin in some Gram-positive bacteria

Three new 8N-alkyl analogues of roseoflavin (MM), i.e., 8-ethylamino- (EH), 8-methylethylamino- (ME), 8-diethylamino-8-demethyl-D-riboflavin (EE), their tetraacetates, and 8-amino-8-demethyl-D-riboflavin (HH) tetraacetate, were synthesized. A relation between the anti-riboflavin activity and the chemical structure of 8N-alkyl analogues (8N-methyl, ethyl) was studied by a restoration by riboflavin (RF) of inhibitory effect of the analogues on a growth of Gram-positive bacteria, i.e., Sarcina lutea, Bacillus cereus, and Staphylococcus aureus. The inhibitory effect of most of the analogues was restored by RF. But in some cases, i.e., 8-methylamino-8-demethyl-D-riboflavin (MH) in Sar. lutea and MM in Staph. aureus, the effect was not completely restored. Apparently, the inhibition in early phase of growth was restored, but the maximum growth was still suppressed. The non-alkylated amino analogue (HH) showed only unrestorable suppression of maximum growth in Sar. lutea. Of restorable effect by RF of N-alkyl analogues, approximate decreasing orders of anti-RF activity were as follows. Dialkylated analogue greater than monoalkylated. HH showed insignificant anti-RF activity. In each group, methylated analogue greater than ethylated. In B. cereus monoalkylated analogues, and in Staph. aureus monoalkylated and EE showed no significant inhibitory effect. Redox potentials of the N-alkyl analogues were measured, and a definite relation between the chemical structure and the potential was found (RF = EE greater than ME greater than MM greater than HH greater than EH greater than MH). But the anti-RF activity of the analogues was not completely explained by the difference of the redox potential from RF.

[Relationship between adsorption of microorganisms and the stage of their development]

Bond strength during adsorption of microorganisms depends on their growth stages, as was found by light optical and scanning electron microscopy. The strenth of adsorption often decreases as a culture growth on the surface of an adsorbent. Adsorption of microorganisms is an important ecological process. Under favourable conditions, microorganisms grow at a high rate when they are firmly bound to a solid surface. After abundant growth which deteriorates their microenvironment, microorganisms desorb and are dispersed. Such is a distribution of microorganisms growing on solid surfaces.

[Antagonistic interrelationships between the staphylococci and Sarcina isolated from the upper respiratory tracts of virtually healthy persons]

The antagonistic activity of staphylococci isolated from the mucosa of the anterior parts of the nose of practically healthy persons was studied with respect to 102 strains of Sarcinia. Staphylococcus aureus had the most pronounced inhibitory effect on Sarcinia. No difference in the antagonistic activity of the staphylococci isolated from the carriers of the permanent and transitory types was found. However, Staphylococcus aureus isolated from the permanent carriers had a broader activity spectrum.

Motility tracks: technique for quantitative study of bacterial movement

A method for recording movements of bacteria in time and space on a single photograph is described. Quantitative information on the behavior of various motile organisms may easily be obtained for comparative studies. The method possesses certain advantages over cinematography, and illustrations of applications of the technique are presented.