John Afseth

Accumulation of Cu and Zn in human dental plaque in vivo.

The rentention of copper and zinc in dental plaque in vivo after repeated mouth rinses with aqueous solutions of salts of these elements was measured by neutron activation analysis. The reduction in a

The in vivo effect of glucose solutions containing Cu+ + and Zn+ + on the acidogenicity of dental plaque

A series of experiments were performed to evaluate the lowest concentration of copper or zinc effective in reducing the acidogenicity of dental plaque in vivo when applied simultaneously with a carbohydrate challenge. The effect of a combination of sub-effective concentrations of these metals was also determined. The results showed a significant reduction in acid production in plaque challenged with glucose solutions containing 0.25 mM CuSO4 or 5.0 mM Zn (C2H3O2).2 as compared to glucose solutions alone. Neither 0.1 mM copper sulphate nor 2.5 mM zinc acetate reduced the acidogenicity of plaque significantly, whereas a combination of these subeffective concentrations was effective. The low metal concentrations causing reduction in acid formation in this study may be explained by the inhibiting substances reaching the bacteria at the same time as the substrate. The synergistic effect of the combination of low concentrations of copper and zinc is consistent with the view that these metals effect dental plaque by the same mechanisms.

Microbial composition, pH-depressing capacity and acidogenicity of 3-week smooth surface plaque developed on sucrose-regulated diets in man

The effect of 3 weeks dietary supplementation, respectively restriction, of sucrose on gingival smooth surface plaque was assessed in 4 caries-inactive adults. Plaque samples collected from discrete t

Clinical Experiments with a Toothpaste Containing Amyloglucosidase and Glucose Oxidase

A toothpaste containing sodium fluoride and enzymes activating the antibacterial lactoperoxidase-thiocyanate system was tested in a model with sucrose-induced plaque formation. The dentifrice did not

The effect of a combination of copper and hexetidine on plaque formation and the amount of copper retained by dental plaque bacteria

Zn++ in combination with hexetidine exerts a synergistic plaque inhibition. Studies in our laboratory on the mechanism of this effect suggested that Cu++ and hexetidine may have a similar combination effect. This hypothesis was tested in vivo on a human test panel in a double-blind crossover study. The amount of Cu++ retained by plaque bacteria in vitro was also evaluated. Seven volunteers rinsed with the solutions for 1 min twice daily for 5 days. The test solutions were H2O, 1.0 mM CuSO4, 2.0 mM hexetidine, and the last two in combination. During the test period no oral hygiene was allowed, and sucrose-containing chewing gum was used to enhance plaque formation. The plaque index scores after rinsing with the combination were significantly (p less than 0.05) lower than those of the other solutions. The effect of hexetidine on Cu++ retention in plaque bacteria was evaluated in plaque samples (n = 3) grown anaerobically overnight in PPLO medium. The bacteria were washed five times, digested in concentrated HNO3, and Cu++ determined by atomic absorption. The presence of hexetidine resulted in a significantly greater amount of Cu++ retained by bacteria at all CuSO4 concentrations. It is suggested that the nonpolar nature of the hexetidine molecule enables Cu++ bound to hexetidine to pass into the bacterial cell. Within the cell, Cu++ can interfere with bacterial metabolism, giving a reduction in plaque growth.

Clinical Experiments with a Mouthrinse Containing Sanguinarine Chloride

A mouthrinse containing 0.1% (w/v) of the isoquinoline alkaloid sanguinarine chloride with 1,000 ppm Zn was tested in a model with sucrose-induced plaque formation. Rinsing twice daily for 1 min with

Effect of a Combination of Copper and Hexetidine on the Acidogenicity and Copper Accumulation in Dental Plaque in vivo

A double-blind crossover study on 4 adult volunteers was performed to evaluate the effect of hexetidine on Cu2+ accumulation in dental plaque as well as a possible enhanced effect of copper on inhibition of acid production in the presence of hexetidine. The experimental period was 5 days. No oral hygiene was allowed, and sucrose-containing chewing gum was used to enhance plaque formation during the test period. In order to evaluate the effect on pH, the test persons rinsed with a 15% glucose (w/v) solution on the 5th experimental day. Plaque pH values recorded before and 5 min after the rinse served as control values. One hour later the test persons rinsed with 10 ml of the test solutions for 1 min. Glucose rinses with pH measurements 5 min after the rinse were carried out 0, 3, and 7 h after the test agents were used. The combination of 1.0 mM copper and 2.0 mM hexetidine gave a significant (p less than 0.05) inhibition of acid production at all times compared both to the controls and to each of the test agents separately. Plaque samples were collected with a toothpick immediately before a 1-min rinse with 10 ml of the test solutions. Subsequent plaque samples were taken 5 min and 3 and 8 h after a rinse from corresponding tooth surfaces. Dry weight was estimated, the plaque bacteria digested by HNO3, and the amount of Cu2+ determined by atomic absorption.(ABSTRACT TRUNCATED AT 250 WORDS)

Copper in approximal plaque from conventional and non-gamma-2 amalgam restorations

Differences in copper concentrations found in plaque adjacent to conventional compared with copper-rich non-gamma-2 amalgam fillings were evaluated. Plaque was sampled at baseline and up to 2 months after polishing of two to four fillings of each type of amalgam in six patients. Copper concentrations of several hundred ppm were found, with higher values in plaque sampled from copper-rich amalgam. However, the copper release from the copper-rich amalgam probably has very little influence on plaque ecology owing to a relatively low copper ion activity because of stable copper complexes in plaque.