Triclosan inhibits histamine-induced inflammation in human skin.

Previous studies indicate that triclosan reduces the pain and other symptoms after chemically-induced inflammation in the oral mucosa and skin when sodium lauryl sulfate (SLS) is used as an irritant. The aim of the present study was to examine whether triclosan has an effect on the inflammation in human skin caused by intradermal administration of histamine. 9 female volunteers participated in a double-blind study, and skin patch tests were performed in 2 series. In the 1st, the skin was pre-treated for 1 h with triclosan before the histamine was applied. In the 2nd, the histamine reaction was elicited first and triclosan applied subsequently. The effect of triclosan on the weals formed in the skin after histamine application was measured. It was found that triclosan reduced the size of the weals markedly when triclosan was applied after the weals were formed, and that pre-treatment of the skin had only a slight effect. It is assumed that triclosan has an effect on the cascade reactions of inflammation elicited by histamine. 2 other phenols tested in the same study had similar effects.

Experiments with two-phase plaque-inhibiting mouthrinses.

Reports indicate that oil/water mouthrinses with an aqueous phase containing an antibacterial agent, reduce the amount of volatile bacterial products in expiration air compared with aqueous mouthrinses. These systems have not, however, been tested concerning antiplaque activity. The aim of the present study was to examine the plaque-inhibiting effect of a mouthrinse with an aqueous phase containing 0.2% chlorhexidine (CHX) and an oily phase (soya oil) containing 0.3% triclosan. A test panel rinsed with the mouthrinses twice daily for 4 d. The mouthrinse containing CHX and triclosan in two phases was significantly better than the negative control (water). However, it was not as effective as the rinse consisting of an aqueous phase with chlorhexidine combined with an oily phase without triclosan. A two-phase mouthrinse with soya oil containing 0.3% triclosan was not superior to soya oil alone, and the combination of CHX and triclosan in a two-phase rinse was not as effective as 0.1% CHX alone in water. No beneficial effect on plaque inhibition could thus be found by using a two-phase system with two different antibacterial agents (one water soluble and one lipid soluble). Soya oil without triclosan rendered higher plaque inhibition than the control, presumably due to formation of a hydrophobic layer on the tooth surfaces.

Organic solvents and oils as vehicles for triclosan in mouthrinses: a clinical study.

Previous experiments have shown that the nature of the detergents used in aqueous triclosan-containing mouthrinses affects the plaque-inhibiting effect of these mouthrinses, probably because of the properties of the micelles formed. It has also been shown that triclosan has a marked plaque-inhibiting effect when dissolved in pure propylene glycol. The aim of the present study was to compare the clinical effect of triclosan dissolved in oils and in the pure solvents glycerol (GLY) and polyethylene glycol (PEG). A test panel of 12 volunteers rinsed with the allocated mouthrinses for 4 days in a double-blind, crossover study. Three different oils were tested: olive oil, soy oil, and sunflower seed oil, as well as PEG and GLY. Triclosan was used in a 0.3% concentration to facilitate comparison with previous studies. However, only 0.15% triclosan was added to the GLY-containing rinse (maximum soluble concentration). In addition, soy oil without triclosan was tried. The mean plaque score for water was 1.42 +/- 0.19; for olive oil, 1.08 +/- 0.34; for soy oil with triclosan, 0.95 +/- 0.35; for pure soy oil, 0.94 +/- 0.09; for sunflower seed oil, 1.19 +/- 0.19; for PEG, 1.04 +/- 0.22; and for GLY, 1.12 +/- 0.28. The results indicate that triclosan dissolved in oils loses its clinical effect. However, oils in themselves exhibit significant plaque inhibition. In vitro tests showed no antibacterial activity of triclosan dissolved in oils. Toothpastes and mouthrinses contain flavoring oils and occasionally also GLY and PEG. Such substances may well interfere with the clinical effect of triclosan in these products.(ABSTRACT TRUNCATED AT 250 WORDS)

Significance of choice of solvents for the clinical effect of triclosan-containing mouthrinses.

The aim of this study was to investigate the plaque-inhibiting effect of triclosan. It is known that triclosan and sodium lauryl sulfate (SLS) have a marked inhibitory effect. However, since SLS has a plaque-reducing effect in itself, the relative importance of triclosan and the surfactant is undecided. Twelve dental students participated in the trial, during which oral hygiene was suspended for 4-day periods when the different mouthrinses were used twice daily. The following mouthrinses were used: A, water (negative control); B, 0.2% chlorhexidine acetate (CHX) (positive control); C, 0.3% triclosan in water-free propylene glycol (PG); D, 0.3% triclosan with 1.5% SLS in PG; E, 0.15% triclosan in PG; F, 0.075% triclosan in PG; G, 0.3% triclosan in diluted PG (1:8 in water) with 1.5% SLS; and H, 0.3% triclosan in 0.5% sodium carbonate. The results showed that triclosan dissolved in the organic solvent PG had a significant plaque-inhibiting effect, whereas, dissolved in alkali, it had a negligible effect. The addition of SLS to PG somewhat reduced the antiplaque activity, and the aqueous solution of triclosan had markedly less effect. Lower concentrations of triclosan exhibited less clinical effect than higher concentrations. It can be concluded that triclosan alone, dissolved in a suitable solvent, has an antiplaque effect. The study confirmed the hypothesis that the nature of the detergent or organic solvent used to dissolve triclosan affects its clinical effect markedly.

Experiments with triclosan-containing mouthrinses: dose response--and an attempt to locate the receptor site(s) of triclosan in the mouth.

A double-blind cross-over clinical study was performed on eight volunteers to determine the plaque-inhibiting effect of different triclosan- and sodium lauryl sulfate (SLS)-containing mouthrinses. An attempt was also made to locate the binding site(s) of triclosan in the oral cavity. After the volunteers rinsed for four days with solutions of various concentrations of triclosan and/or SLS, plaque deposits were scored according to the Silness and Löe Plaque Index. The study showed that 0.15% and 0.3% concentrations of triclosan yielded a comparable plaque-inhibiting effect in vivo. Furthermore, the 0.1% triclosan with 1.5% SLS exhibited a higher (though not significant) effect than 0.1% triclosan with 0.75% SLS. The mouthrinse containing 0.05% triclosan and 0.25% SLS was as effective as the two mentioned mouthrinses containing 0.1% triclosan. Collectively, the results indicate that triclosan alone has an antiplaque effect, independent of the effect of SLS. Furthermore, the results suggest that the SLS monomers may play a role as carriers of triclosan and that the teeth are not the only binding site of triclosan, since topical application of 0.3% triclosan failed to produce a clinically discernible effect.

Triclosan-containing mouthwashes--does the nature of the solvent influence their clinical effect?

The effect of triclosan on plaque inhibition was studied with various solvents. Eight subjects used the solutions as mouthwashes twice daily for 4 days while refraining from any other form of oral hygiene. Bacteriologic tests were also done with the same solutions. The study showed that the nature of the substance used to dissolve triclosan may be of clinical significance. Solutions of triclosan in polyethylene glycol, glycerol, or 3% sodium lauryl sulfate (SLS) alone showed marked antiplaque effect. (The first two solutions both contained 1.5% SLS). However, triclosan dissolved in Tween 80 had only a negligible clinical effect. In vitro experiment showed that antibacterial tests did not correlate well with clinical data. It is proposed that the nature of the micelles of the detergents which are used to dissolve triclosan is of significant importance. Strongly charged micelles such as SLS show clinical effect, whereas less charged micelles of SLS/Tween 80 or uncharged micelles of Tween 80 alone appear not to have this effect.

Effects of oral rinsing with triclosan and sodium lauryl sulfate on dental plaque formation: a pilot study.

Mouthwashes containing 0.3% or 0.15% triclosan in combination with 1.5% sodium lauryl sulfate (SLS) produced a significant reduction in plaque formation in a test panel of 11 students who refrained from oral hygiene during the test periods, during which they rinsed twice daily with different mouthwashes. Pl.I. was evaluated after each test period. A mouthwash containing only 1.5% SLS inhibited plaque to almost the same degree. In both cases, the major effect was on the buccal/lingual surfaces, where score 2 was changed to score 0. Addition of triclosan appeared to reduce the untoward side-effects of mouth-washes containing SLS alone (i.e. desquamation and a burning sensation in the mouth).

Adaptation of dental plaque to sorbitol after 3 months' exposure to chewing gum.

Five subjects used sorbitol-containing chewing gum for a period of 12 wk. Plaque was collected before and after the sorbitol exposure and also 12 wk after the termination of the exposure. The individual plaque samples were incubated with 14C-labeled sorbitol, and the medium was examined by HPLC. It was found that plaque samples from all subjects catabolized more sorbitol after the exposure. The flora adapted to sorbitol was persistent, and all the subjects had a higher capacity for metabolizing sorbitol even 12 wk after the end of the sorbitol exposure than before it. Formate, acetate, ethanol, and lactate were the major catabolites of sorbitol. Small amounts of succinate and propionate were found in some samples.

Evidence for xylitol 5-P production in human dental plaque.

The Turku sugar studies indicated that xylitol may possess a caries-therapeutic effect. More recent data show that xylitol exhibits a bacteriostatic activity on a wide range of bacteria based on uptake and expulsion of xylitol. Intracellular xylitol 5-P appears to be a key substance associated with inhibition of bacterial metabolism by xylitol. This has been shown in studies with pure strains of bacteria, mainly Streptococcus mutans. The aim of the present study was to examine if production of xylitol 5-P occurs in freshly collected dental plaque which is exposed to labeled xylitol. Plaque extracts were analyzed by thin-layer chromatography combined with autoradiography and high performance liquid chromatography. Strong indications were obtained that xylitol 5-P is readily produced by dental plaque. No other significant xylitol metabolites were identified. The bacteriostatic properties of xylitol in plaque are a mechanism which may well account for the caries-therapeutic effect of xylitol.

Further in vivo studies on the plaque-inhibiting effect of chlorhexidine and its binding mechanisms.

The aim of the present study was to investigate the relative importance of chemical groups in the oral cavity which bind chlorhexidine of clinical significance. This was performed by clinical experiments where a test panel of 11 individuals rinsed with chlorhexidine at pH 7, pH 5.5, and pH 3. Rinsing with 0.02 M EDTA was performed prior to the chlorhexidine rinse, because this procedure has been shown to enhance the antibacterial effect of chlorhexidine in vitro. However, pre-rinses with EDTA did not increase the clinical effect of chlorhexidine. Bacteriologic tests showed comparable antibacterial effect of chlorhexidine at pH 7 and pH 3. Mouthrinses of pH 7 and pH 5.5 had comparable plaque-inhibiting effects, whereas the effect of a rinse of pH 3 was not different from that of the placebo. This finding is interpreted to suggest that primary phosphate (pK about 2) is an important receptor site for chlorhexidine, whereas secondary phosphate (pK = 7.0) is of negligible importance. Previous studies have clearly shown that phosphate binds chlorhexidine. The lack of clinical effect at pH 3 is probably due to precipitation of salivary proteins by hydrogen ions, making primary phosphate groups unavailable for interaction with chlorhexidine.

Metabolism of xylitol in dental plaque.

It has been reported previously that xylitol added to glucose used to challenge dental plaque in vivo caused a reduced acid formation. The aim of the present study was to approach the mechanism by which xylitol may affect glucose catabolism in plaque bacteria. Suspensions of freshly collected 4-day-old plaque bacteria were incubated, one batch with labeled xylitol, one with labeled glucose, in vitro at 37 degrees C. Samples of cells were taken out at time intervals, collected on paper discs and subjected to scintillation counting. It was observed that the plaque bacteria took up xylitol, the uptake increasing with incubation of more than 3-4 h, whereas the same cells took up glucose immediately. Cells which had taken up xylitol were extracted with boiling water, extracts concentrated and applied on thin-layer chromatography sheets. A radioactive component with mobility like xylitol-5-phosphate was isolated from the cell extracts, and also a component where labeled xylitol was associated with macromolecules. It is suggested that the accumulation of the metabolities within the cells inhibits glycolysis.

Importance of teeth and tongue as possible receptor sites for chlorhexidine in relation to its clinical effect.

Teeth have previously been shown not to be of any major importance when quantitatively measuring the retention of chlorhexidine in the oral cavity. Only a few studies have examined the significance of the binding of chlorhexidine to the tongue in relation to its plaque inhibiting effect. The present study was therefore carried out to further examine these possible chlorhexidine receptor sites in the oral cavity in relation to its known antibacterial effect at the teeth surface. Two daily applications of chlorhexidine on the teeth in the right side of the maxilla, against a contralateral water control, both in combination with a sucrose challenge six times daily, showed no significant reduction of plaque formation when compared to an application of sucrose used alone. Two daily applications of chlorhexidine on the tongue, again combined with sucrose challenge, also showed no significant plaque inhibiting effect. The results obtained indicate that neither the teeth nor the tongue seem to be of major importance as receptor sites for chlorhexidine in the oral cavity as related to its observed clinical effect.

Effect of aqueous solutions of sorbitol-xylitol on plaque metabolism and on growth of Streptococcus mutans.

The present study showed that the growth of Streptococcus mutans strain GS5 was inhibited by xylitol, and this indicates together with previous reports that this is a common phenomenon in this species. Sorbitol was found to increase the growth of S. mutans strains OMZ 176 and GS5 slightly compared with cultures with no external carbon source. Addition of small amounts of xylitol to the sorbitol cultures gave a growth below that of cultures with no extra carbon. Dental plaque challenged with sorbitol gave a small pH drop whereas xylitol caused a negligible decrease in pH. Sorbitol-xylitol challenges gave less acid production than sorbitol challenges alone.