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 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.

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.

Effects from pretreatment of stannous fluoride versus sodium fluoride on enamel exposed to 0.1 M or 0.01 M hydrochloric acid.

Preventing enamel erosions caused by acidic soft drinks or from vomiting during eating disorders is a challenge in current dental research. The aim of this study was to examine whether pretreatment of dental enamel with a solution of 0.4% SnF2 could prevent dissolution of human enamel exposed to solutions of 0.1 M HCl, pH 1.2 or 0.01 M HCl at pH 2.2. Human enamel was pretreated for 18 h with a solution of 0.4% SnF2 and with control solutions of 2% NaF or distilled water, and then exposed to HCl solutions. Similar experiments were performed with teeth treated for 2 min SnF2 and then 4 min HCl. The effect was monitored by scanning electron microscopy (SEM) and by chemical analysis. At pH 2.2, NaF and water treatments showed minor inhibition of enamel dissolution, whereas SnF2 inhibited demineralization significantly also after 2 min pretreatment and 4 min HCl exposure. At pH 1.2, SEM showed severe dissolution of the enamel surfaces regardless of pretreatment. As pH of stomach vomit is usually > 1.5, SnF2 may be an interesting agent for use in the treatment and prevention of dental erosions even in patients with frequent vomiting episodes.

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.

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.

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.

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.

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.

Alkali-soluble fluoride deposition on human enamel exposed to monofluorophosphate: containing toothpastes in vitro / Deposição de fluoreto-alcalino solúvel no esmalte humano exposto ao monofluorfosfato presente em pastas dentárias \"in vitro\"

Enamel specimens from unerupted third molars were treated with the supernatant of monofluorophosphate (MFP) containing toothpaste slurries in water. Calcium fluoride-like particles were formed on the enamel surface during a 24h exposure. The globules were soluble in alkali. More particles were seen on enamel treated with a toothpaste containing both MFP and NaF. The experiments showed that the calcium fluoride-like material formed on enamel after treatment with (MFP) containing toothpaste probably originates from the free fluoride present in the pastes. The relatively moderate deposition of fluoride may be of clinical significance because the teeth are so frequetly exposed to toothpaste. No firmly bound fluoride was found on treatment of enamel with (MFP) containing toothpaste

Acquisition of alkali-soluble fluoride by enamel through treatment with NaF-containing toothpastes in vitro / Obtenção de fluoreto alcalino solúvel pelo esmalte através de tratamento com NaF inseridos em pastas de dente in vitro

The first aim of the present study was to examine if alkali-soluble fluoride (calcium fluoride-like material and adsorbed fluoride) forms when a Naf-containing toothpaste is applied on human enamel surface in vitro. The centrifuged supernatants of toothpastes dissolved in distilled water were used and four different commercial Naf-containing toothpastes were tested. The second aim was to investigate if pyrophosphate would interfere with the deposition of alkali soluble fluoride. The formation of alkali-soluble fluoride was determined by chemical analysis and visualized by scanning electron microscopy (SEM). It was ascertained that all tested toothpastes contained free fluoride according to the manufactures' specifications. It was shown that they promoted deposition of alkali soluble fluoride on the enamel surface. The amount of deposited material increeased with the time of exposure. The clinical effect of a NaF-containing toothpastes may thus well depend on an initial formation of alkalisoluble fluoride. Fluoride from this reservoir may adsorb onto the enamel crystals and inhibit further demineralization or increase the rate of remineralization during cariogenic challenges. It was also demonstrated that pyrophosphate did not interfere with the deposition of alkali soluble fluoride

A importância do fluoreto de cálcio como reservatório de flúor na superfície do esmalte dentário / The importance of calcium fluoride as fluoride reservoir on enamel surface

Discutiu-se o significado do fluoreto de cálcio depositado no esmalte dentário da aplicação tópica de flúor. Com base na literatura, são revistos os conceitos do mecanismo cariostático do flúor após tratamentos tópicos, nos quais o fluoreto de cálcio parece ser o elemento essencial ao controle e a prevenção da cárie dentária. Sua formação e deposição na superfície do esmalte, com posterior liberação de íons flúor em pH baixo, parece ser a explicação para o efeito tópico. Assim os cristais de fluoreto de cálcio podem funcionar como fontes de íons flúor no esmalte e na placa, controlados pelo pH e que são utilizados durante os ataques da cárie. Alguns aspectos das reações relacionadas aos tratamentos tópicos fluoretados são discutidos