Short-term effect of strontium- and zinc-containing toothpastes and mouthrinses on volatile sulphur compounds in morning breath: a randomized, double-blind, cross-over clinical study.

Zinc (Zn) reduces the formation of volatile sulphur compounds (VSCs) associated with oral malodour. Although strontium (Sr) is included in some products for reducing dental hypersensitivity, it may also have anti-halitosis properties. This randomized, double-blind, cross-over clinical study compared the anti-VSC effect of brushing with commercial toothpastes and rinses containing Zn and Sr. The volunteers (n = 30) either brushed/rinsed with/without tongue brushing using Zn-containing toothpaste/rinse, Sr-containing toothpaste/rinse, or placebo (control). Volatile sulphur compounds [hydrogen sulphide (H2 S) and methyl mercaptan (CH3 SH)] were measured, in morning breath, using gas chromatography. The anti-VSC effects of the test toothpastes and test rinses were significantly better than the anti-VSC effects of the respective controls. Toothbrushing with test toothpastes gave median reductions, compared with the control, of 70% for H2 S and 55-57% for CH3 SH. Rinsing with the Sr- and Zn-containing solutions had the same anti-VSC effect as toothbrushing and tooth- and tongue brushing with the Sr- and Zn-containing toothpastes. Zinc-containing rinse resulted in a significantly higher median salivary level of Zn compared with brushing with Zn-containing toothpaste, although this effect did not correlate with the anti-VSC effect. It can be concluded that the Sr- and Zn-containing toothpastes and the Zn- and Sr-containing rinses, when used in the evening, are equally effective in reducing morning-breath VSCs the following day.

On inhibition of dental erosion.

OBJECTIVE: To examine the erosion-inhibiting effect of different concentrations of hydrofluoric acid. MATERIALS AND METHODS: Thirty-six human molars were individually treated with 10 ml of 0.1 M citric acid for 30 min (Etch 1), acid was collected and stored until analysis. The teeth were randomly divided into six groups and then individually treated with 10 ml of one of six dilutions (from 0.1-1%) of hydrofluoric acid. The teeth were then again treated with citric acid (Etch 2). The individual acid samples from Etch 1 and 2 were analyzed for calcium by flame atomic absorption spectroscopy and difference in calcium loss was calculated. RESULTS: The highest erosion inhibiting effect was obtained in groups with the highest concentrations of hydrofluoric acid, where the pH was lowest, below pKa of 3.17, thus the hydrofluoric acids being mainly in an undissociated state. DISCUSSION: Diluted hydrofluoric acid is present in aqueous solution of SnF2 and TiF4 (which are known to inhibit dental erosion): SnF2 + 3H2O = Sn(OH)2 + 2HF + H2O and TiF4 + 5H2O = Ti(OH)4 + 4HF + H2O. It is also known that pure, diluted hydrofluoric acid can inhibit dental erosion. Teeth treated with hydrofluoric acid are covered by a layer of CaF2-like mineral. This mineral is acid resistant at pH < 3, because it was formed at this pH. CONCLUSION: The erosion-inhibiting effect is due to formation of an acid resistant mineral, initiated by tooth enamel treatment with hydrofluoric acid. Hydrofluoric acid is different in having fluoride as a conjugated base, which provides this acid with unique properties.

A replica technique for studying the effect of fluoride solutions on enamel erosion.

UNLABELLED: The aim of this in vitro study was to develop a replica technique aimed at reproducing an enamel surface exposed to erosive challenge. The replica technique was then used to compare the effect of treating enamel with different fluoride (F) solutions using an in vitro erosion model. Human molar teeth were split in two (total n=34 specimens), and half of each specimen was isolated with impression material. Part I: 10 specimens were exposed to either 0.18% or 1.8% citric acid, the impression material was removed and replicas were prepared. All specimens and replica models were analysed by profilometry and SEM. Part II: 24 specimens were treated with native 0.1 mol/L F-solutions (HF, SnF2, NaF and TiF4), the impression material was removed, and the specimens were then exposed to 1.8% citric acid. Replicas were prepared and analysed by profilometry and SEM. The median height difference between the F-treated areas and the non-treated areas for each F-solution was measured. SEM micrographs were analysed qualitatively blind bytwo of the authors. RESULTS: Part I--Replicas showed good topographical reproduction of the tooth specimens. Part II--HF had a significantly greater erosion-inhibiting effect than the other fluoride solutions at 0.1 mol/L F as shown by profilometry. SEM revealed a clearly defined border between F-treated and non-treated surfaces only for specimens treated with HF- and TiF solutions. In conclusion, the present replica technique was able to differentiate between the effect of treating enamel with different fluorides against dental erosion in vitro. The technique should be tested further for possible use in situ and in vivo.

A new mouthrinse combining zinc and chlorhexidine in low concentrations provides superior efficacy against halitosis compared to existing formulations: a double-blind clinical study.

OBJECTIVE: Volatile sulfur compounds (VSC), mainly derived from bacteria located in deep crypts at the back of the tongue and from periodontal pockets, are responsible for approximately 90% of halitosis (bad breath, malodor). The objective of this double blind clinical study was to assess the clinical efficacy of a new formulation for halitosis containing a combination of zinc (0.3% Zn) and chlorhexidine (0.025% CHX) in low concentrations. The new formulation was compared to some widely used and commercially available formulations containing various enzymes and antibacterial agents in a clinical setting under controlled conditions. METHODOLOGY: Ten healthy volunteers participated in this study (5 female, 5 male, mean age: 46.6, range: 26-79). Each participant served as their own control, and neither the investigator nor the ten test subjects knew which formulation they were testing at any given time (double-blind design). Baseline H2S data were obtained by cysteine rinsing for 30 seconds, 90 seconds mouth closure, and gas chromatographic (GC) analysis of mouth air. On separate days, each participant then rinsed for 60 seconds with 10 ml of each of the eight various formulations. Cysteine rinses were repeated at 1 hour, 2 hours, and 3 hours, and GC measurements of oral H2S levels were again recorded. RESULTS: The test rinse (0.3% Zn + 0.025% CHX) reduced the intraoral H2S levels to 0.16% of control (range: 0.01-0.54%) after 1 hour, 0.4% after 2 hours, and 0.75% after 3 hours, providing superior efficacy in reducing H2S compared to the other formulations tested (p < 0.05). CONCLUSION: A combination of Zn and CHX in low concentrations seems to be the most efficient way to remove the VSC that causes bad breath at present. Studies are underway to further explore the extraordinary efficacy of this combination (close to 100%), suggesting a specific mode of action and a synergistic effect of these two components.

Etching effect of acidic fluorides on human tooth enamel in vitro.

OBJECTIVE: This in vitro study aimed to examine the etching effect of acidic fluoride solutions on enamel. MATERIALS AND METHODS: 24 human teeth divided into 48 enamel-specimens were partly isolated with impression material. Specimens were exposed for 10 min to 20ml of the following solutions: 1.6% TiF4, 3.9% SnF2, 0.2% HF and 1.8% citric acid (CA). The isolation was removed and 24 specimens analysed by profilometry (Δheight: exposed/isolated enamel surfaces, surface roughness parameters). For the remaining 24 specimens [Ca(2+)] in the test solutions was analysed by atomic absorption spectroscopy. RESULTS: Median Δheights (µm) after exposure were: TiF4 0.07, SnF2 -0.03, HF -0.14 and CA -5.92. TiF4-exposed surfaces showed both deposits and etched areas and exhibited statistically significant different surface roughness parameters compared to the HF- and SnF2-exposed surfaces. Median [Ca(2+)] values (ppm): TiF4 1.88, SnF2 0.11, HF 0.10 and CA 2.17. CONCLUSION: At the [F] tested in this study it can be concluded that SnF2- and HF solutions had negligible erosive effects on enamel. TiF4 solution resulted in an incomplete surface deposition associated with calcium dissolution suggesting that TiF4 applied as solution may not be advisable.

Effect of acidic fluoride treatments on early enamel erosion lesions--a comparison of calcium and profilometric analyses.

OBJECTIVE: The protective effect of fluoride solutions against acidic challenge on enamel was tested in vitro using calcium- and profilometer analyses. METHODS: HF-, SnF(2)-, TiF(4)- and NaF solutions (0.1M F(-), with a pH of 2.0, 2.9, 1.5, 7.3, respectively) and H(2)O were tested on a total of 60 enamel specimens divided into 10 groups. Prior to and after F-treatment five groups were exposed for 1 min to 0.01 M citric acid, and the other five groups for 10 min to 0.1M citric acid. Enamel specimens were measured by profilometry at baseline and before and after each acidic challenge. [Ca] in the collected citric acid samples was measured by atom absorption spectroscopy (AAS). DeltaCa and Delta surface height were calculated for each specimen and the data were analysed using one-way ANOVA, Tukeys test and Pearson r correlation. RESULTS: AAS showed that the acidic F-treatments significantly reduced enamel dissolution for both the 1 min and 10 min acidic challenge. Profilometry showed no significant differences between the F-solutions for the 1 min groups. Significant differences could be seen between the fluorides for the 10 min groups and there was a large correlation between the profilometric and AAS results. In conclusion, all fluoride solutions reduced enamel dissolution when specimens were exposed to citric acid. CONCLUSIONS: The profilometer was not sensitive enough to measure the effects of the different fluorides against a low acidic challenge. AAS was able to show these differences and for the 10 min acidic challenge there was a good correlation between the results from the two methods.

Effect of stannous fluoride toothpaste on erosion-like lesions: an in vivo study.

It has recently been shown that stannous fluoride (SnF(2)), in the form of aqueous solutions and as toothpaste, can reduce the dissolution of enamel in erosive acids in vitro and in situ. The aim of this study was to compare the effect of toothpastes containing SnF(2) or NaF on enamel dissolution using an in vivo model. Four healthy anterior teeth in each subject (n = 20) were exposed to diluted citric acid (100 mmol l(-1) or 10 mmol l(-1)) applied using a peristaltic pump (5 ml @7 ml min(-1)) and the acid was collected in a test tube before and after application of the respective toothpastes (etch I and etch II). Toothpaste was applied to the labial surfaces with a soft brush (four applications, each of 1-min duration), with gentle water rinsing between applications. Each subject had one pair of teeth treated with each of the test toothpastes. Enamel dissolution was examined by assessment of calcium content in the citric acid applied before and after the treatment with toothpaste. The results indicate that the SnF(2) toothpaste markedly reduced the dissolution of teeth in vivo (etch II < etch I), whereas the NaF toothpaste provided no protection (etch II > etch I). Toothpaste appears to be an acceptable vehicle for SnF(2) and maintains the dissolution-reducing effect exhibited by aqueous solutions of this fluoride salt.

The oral anti-volatile sulphur compound effects of zinc salts and their stability constants.

Volatile sulphur compounds (VSC) produced in the oral cavity, are a major cause of oral malodour. Zinc (Zn) ions inhibit VSC formation. The objective of this study was to examine whether Zn salts with low stability constants were more suitable as sources of Zn in lozenges than salts with high stability constants. The former provide free Zn ions upon dissolution in water, whereas the latter provide almost no free Zn. Identical lozenges containing Zn-acetate and -gluconate, which have low stability constants, and Zn citrate and amino acid-chelated Zn, which have extremely high stability constants, were tested. All the lozenges contained 0.9% w/w Zn. Ten volunteers sucked the lozenges until dissolved, and oral VSC were measured by gas chromatography. Zn-acetate, -gluconate and -chelate had an impressive anti-VSC effect even 3 h after the lozenges were taken. Zn citrate had significantly less effect than the other lozenges except Zn acetate after 2 and 3 h. It was concluded that the anti-VSC effect was not related to the stability constants of the Zn compounds tested. Alternative ligands. with stronger affinity for Zn than the ligands in the lozenges, must be present in the oral cavity to explain these results. It is suggested that the sulphide ion may serve this function.

Inhibition of orally produced volatile sulfur compounds by zinc, chlorhexidine or cetylpyridinium chloride--effect of concentration.

Zinc ions, chlorhexidine (CHX) and cetylpyridinium chloride (CPC) are all known to inhibit production of volatile sulfur compounds (VSCs). The objective was to examine the anti-VSC dose-response effects of each of the above agents. Oral malodor was induced in 13 test subjects using the cysteine challenge method. The oral VSC response to rinses with 6 mm l-cysteine (pH 7.2) before and 1, 2 and 3 h after rinsing with zinc ions (Zn2+: 0.1, 0.3 and 1.0%), CHX and CPC (0.025 and 0.2%) was measured. Mouth air was analysed for VSC by gas chromatography (GC) according to current methodology. Zinc had a marked dose- and time-dependent anti-VSC effect. Zinc at 1% concentration had a somewhat unpleasant taste, whereas the lowest concentration was found acceptable. Chlorhexidine maintained a moderate anti-VSC effect over time. At 3 h, 0.2% CHX was the most effective agent but tasted relatively unpleasant. Cetylpyridinium at a concentration of 0.2% was only marginally more effective than 0.025% CHX over the 3 h, while 0.025% CPC had no better anti-VSC effect than water at both 2 h and 3 h. It was concluded that the three test agents demonstrated different anti-VSC kinetics. Although Zn had the best anti-VSC effect at 1 h, 0.2% CHX was at least as effective as 1% Zn at 3 h, most likely as a result of its unique substantivity.

Variation in oral volatile sulphur compound formation.

UNLABELLED: It has been suggested that the level of orally produced volatile sulphur compounds (VSCs) can be of use when monitoring oral malodour or in determining patients at risk of periodontal disease in longitudinal studies. It is not known, however, to what extent the level of VSC in mouth air is a stable, individual characteristic over time. AIM: The hypothesis to be tested was that the level of VSC in mouth air is an individual trait that is stable over time. METHODS: Two groups of dental students participated in the study (n = 30 and n = 11). The amount of available substrate for VSC formation was standardized by rinses with 6 mM aqueous solutions of cysteine (pH 7.2). Part 1 used a Haliineter to measure 'morning breath' and response to cysteine rinses. Part 2 measured response to cysteine rinsing using a gas chromatograph. Repeated measurements provided information concerning the longitudinal intra-individual variations in level of oral VSC formation. RESULTS: Both groups showed large intra-individual variations in oral VSC. The differences were enhanced by cysteine rinses. CONCLUSION: The hypothesis was not supported. Oral VSC levels cannot be taken as diagnostic criteria in a normal population because of marked intra-individual variations over time.

A study of triclosan and its solubilizers as inhibitors of oral malodour.

BACKGROUND: It is known that the detergents or organic solvents used to solubilize lipid-soluble triclosan can affect the biological activities exhibited by this molecule, such as its antibacterial, antiplaque, and anti-inflammatory effects. OBJECTIVE: To examine whether solubilizing agents influence the effect of triclosan against formation of volatile sulphur compounds (VSC), as these are known to be a major component of oral malodour. MATERIAL AND METHODS: Part A: one ml of human whole saliva (n = 10) was incubated for 24 h at 37 degrees C in a closed test tube with addition of 10 micro l triclosan solubilized in alcohol. Part B: in a clinical experiment, VSC formation enhanced by mouth-rinses with cysteine was followed by subjects (n = 9) rinsing with triclosan solubilized in different detergents and organic solvents. The amount and nature of VSC in the saliva headspace and in the mouth air of the test subjects were determined by gas chromatography. RESULTS: Triclosan had a marked dose-dependent effect against VSC in vitro when solubilized in alcohol, independent of the alcohol per se. In vivo, triclosan lost its anti-VSC effect when solubilized in oil, in an uncharged detergent or in a chromophor, whereas it maintained its effect when solubilized in a combination of sodium lauryl sulphate, propylene glycol and water. CONCLUSION: The solubilizing agent influences the anti-VSC effect of triclosan.

Comparative analysis of some mouthrinses on the production of volatile sulfur-containing compounds.

Oral malodor is mainly caused by the presence of volatile sulfur-containing compounds (VSC) produced by proteolytic periodontopathic bacteria in the oral cavity. Different solutions have been used as mouthrinses, trying to reduce malodor, and a large number is on the market. The aim of this study was to compare the effect of three commercially available mouthrinses with a simple inexpensive solution of zinc (zinc acetate 0.1%) on the production of VSC in vivo. Two of the solutions contained triclosan, one of them with fluoride and the other with sodium bicarbonate, and the third one contained herbal components. Seven healthy subjects rinsed with cysteine to induce production of VSC at baseline. After halitosis induction and VSC measurements, the subjects rinsed with the test solution, and mouth airVSC analyses were then performed by means of gas chromatography subsequent to repeated cysteine rinses after 30, 60, and 120 min. The data were calculated as percentage reduction of VSC from baseline. The percentage reduction of VSC decreased over time for all experimental groups. Zinc acetate had clearly the highest percentage reduction, starting from 95.68% at 30 min and with 69.27% after 2 h. The three other mouthrinses produced a VSC reduction of 23.92% 49.86% after 30 min, decreasing to 13.06%-37.09% after 2 h. One-way ANOVA (P = 0.05) was applied, and comparisons showed no differences between the commercially available solutions, but zinc acetate was significantly better than these. It may be concluded that some commercial mouthrinses are markedly less effective than a simple and cheap solution of zinc acetate.