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Do different acids have different effects on the enamel of our teeth?

Do different acids have different effects on the enamel of our teeth?


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Do different acids or acidic solutions corrode the enamel of our teeth at different rates or in different ways? Are these effects present even when controlling for pH?


Acids in Popular Sodas Erode Tooth Enamel

Root beer could be the safest soft drink for your teeth, new research suggests, but many other popular diet and sugared sodas are nearly as corrosive to dental enamel as battery acid.

Prolonged exposure to soft drinks can lead to significant enamel loss, even though many people consider soft drinks to be harmless or just worry about their sugar content and the potential for putting on pounds, the study says.

The erosive potential of colas is 10 times that of fruit juices in just the first three minutes of drinking, a study last year showed. The latest research, published in Academy of General Dentistry (AGD) journal General Dentistry, reports that drinking any type of soft drink hurts teeth due to the citric acid and/or phosphoric acid in the beverages.

"This study simply doesn&rsquot mirror reality," said American Beverage Association spokesperson Tracey Halliday. "The findings cannot be applied to real life situations where people's eating and drinking behaviors are very different and there are many factors at work."

5 percent weight loss

The study measured the acidity, or pH, of 20 commercial soft drinks, including Coke, Pepsi, 7 Up and their diet versions, immediately after cans were opened. Then slices of enamel from freshly extracted teeth were weighed before and after being immersed in the soft drinks for 48 hours.

The result was that the teeth immersed in Coke, Pepsi, RC Cola, Squirt, Surge, 7 Up and Diet 7 Up lost more than 5 percent of their weight, according to the report by Poonam Jain of the Southern Illinois University School of Dental Medicine and her colleagues. (Other sodas brought about losses in the enamel weight in the range of 1.6 percent to 5 percent).

AGD spokesman Kenton Ross said that RC Cola was found to be the most acidic soft drink studied, with a pH of 2.387 (the pH scale ranges from 0 to 14 for most liquids, with 0 being the most acidic and 14 being the least acidic&mdashor most alkaline). Cherry Coke was found to be the next most acidic (pH of 2.522), and Coke was the third most acidic soda tested (pH of 2.525).

Battery acid has a pH of 1.0. Pure water at room temperature has a pH of 7.0.

The results show that a soda's acidity is not the whole story when it comes to tooth erosion. The type of acid in the soda, level of soda and calcium content are also factors. Citric acid is the most erosive acid found in soft drinks and is the predominant acid in non-cola drinks.

"The bottom line is that the acidity in all soft drinks is enough to damage your teeth and should be avoided," Ross said in a prepared statement.

Root beer's advantage

Root beer was found to be the least acidic of all soft drinks, with a pH 4.038 for the Mug brand, Jain and her colleagues found. The reason for the reduced acidity is that root beer is often non-carbonated and contains no phosphoric or citric acids.

A 2006 study reported that orange juice and sports drinks also reduce the surface hardness of tooth enamel, but a cola reduced more&mdashthe dentin, surface enamel and two additional dental components. (Dental erosion refers to the action of acid on the entire tooth surface. Cavities and tooth decay tend to hit targeted areas, such as pits, grooves and spots where teeth are adjacent).

In the past 40 years, many Americans have swapped nutrient-dense milk for sodas and other beverages that are mostly bereft of nutrients. In 1966, Americans drank, on average, 20 gallons of soft drinks and 33 gallons of milk. In 2003, Americans drank an average of 46 gallons of soft drinks and 22 gallons of milk. Milk contains minerals, proteins, vitamins and, most importantly, calcium.

Study shortcomings

No one swishes soda in their mouth for two full days, as was the case with the study, but the corrosive effect of soda starts nearly immediately, Jain's research points out, and increases with time.

Richard Adamson, a scientific consultant to the American Beverage Association, called the study "unrealistic," pointing out, among other things, that toothbrushing was not factored in.

"The most protective factor you have in your mouth is saliva, which has both a diluting and a buffering effect," Adamson told LiveScience. "Of course, you're not going to mirror reality (with the new study)."

"There are many foods which are as important as soft drinks in oral health and dental hygiene," Adamson said. "Fruit and fruit juices and cider and food such as pickles and salad dressing and wine&mdashthose are just as important in regards to general erosion as soft drinks. There is no single food or beverage that is responsible for dental erosion. There are numerous factors. The thing is to enjoy everything in moderation."

Ross recommends that consumers drink soda through a straw, if at all, as that reduces the teeth's exposure to the beverage. One way to reduce soda intake, he suggested, is to drink it only with meals.


Introduction

Tooth erosion is a chronic loss of dental hard tissues (enamel and dentine) caused by acids of intrinsic (gastric) or extrinsic (dietary) origin. To some extent, it is a physiological and age dependent process related to acid containing food intake [1]. A pathological status is reached at the latest when the teeth are so worn that their functionality is impaired [2], but it may also be already perceived by patients and dentists when the appearance of the teeth is affected [1]. In contrast to the physiological status of erosion, no age dependence is found in the pathological form [1]. It is classified as a disease in the WHO ICD10-classification [3].

The prevalence of tooth erosions is high and continuously growing within populations [4]. A recent study from Israel [5] showed a prevalence of between 36.6% in 15-18-year-olds and 61.9% in 55-60-year-olds. In their systematic review, Salas et al. showed a prevalence of 30.4% in 8-19-year-old children and adolescents [6]. Although the prevalence of tooth erosion is high and increasing in many countries, its relevance for oral health is not comparable to caries and periodontitis. For example, no tooth loss is reported due to tooth ersosion in Germany, but 14.1 teeth are lost on average due to caries and periodontitis at the age of 65–74 years [7].

Since no age dependence is found [1], an independent variable may be responsible for severe levels of erosive destruction. Mulic et al. found that gastric acids (reflux or vomiting), fruit juices and soft drinks are risk indicators for erosive wear [8]. This was confirmed in a meta-analysis by Hi et al. where soft drinks showed the highest and statistically significant odds ratio (2.41) for the development of dental erosions [9]. In accordance, Habib et al. found a statistically significant odds ratio of 2.38 for acidic fruit juice consumption [10]. Since the consumption of soft drinks is continuously increasing in developed countries [11], the knowledge about their erosivity is important in dietary and dental counseling. However, Barbour and Lussi stated that “a ranking for the in vivo erosivity of different acidic drinks…is rather complicated if not impossible” [12]. The need for valid data on the erosivity of soft drinks having been recognized, the question arises which methodology could be used to address this problem. To date, several qualitative and quantitative in-vivo, in-situ and in-vitro methods have been used to determine tooth erosivity in enamel and dentine [13,14]. For diet counseling, only quantitative data are relevant. According to Schlueter et al., profilometry is the most commonly applied quantitative method, followed by measurement of surface hardness and microradiography. Measurement of calcium and phosphate release from dental hard tissues in solutions is another common method [13].

Non-contact, 3-D-profilometry is a valid tool in determining surface tissue loss, but it does not allow to measure the mineral loss occurring beneath a pseudo-intact surface [13]. This is possible by microradiography but, like 3-D-profilometry, specimen preparation and analysis are time consuming and require expensive technical equipment. Measuring surface hardness is at least a simple and quick method, but can only show the status of the remaining surface without giving information about lost hard tissue at the surface of the specimen.

A possible simple and meaningful method may be gravimetric analysis. This method evaluates the erosivity by weighing enamel or dentine specimens before and after erosive exposition. To our knowledge, the first and only studies using a gravimetric method were performed by von Fraunhofer and Rogers using a small number of human tooth samples [15,16]. In consideration of the described needs and methodologies, it was the aim of the present study to generate some data for commonly consumed non-alcoholic beverages with a newly developed gravimetric method using bovine tooth specimens. Additionally, the erosivity of chlorinated swimming pool water should be analyzed since pathologic erosion was observed in competitive swimmers [17]. Both aims could be achieved.


We can’t experiment on our own teeth so are using eggs to represent them, as the shell of an egg is made of a similar substance to tooth enamel!

What you’ll need for a tooth decay experiment:

Instructions

  • Pour the same amount of fizzy drink, vinegar, water and tea or coffee into your jars.
  • Add a whole raw egg still in it’s shell to each, cover an extra egg with toothpaste and also place in tea/coffee.
  • Leave for approximately three days.
  • Remove the eggs.
  • Rinse the egg kept in vinegar and rub gently until the shell comes away.

Results of our tooth decay experiment with egg shells


You should see staining on both the fizzy drink and tea/coffee egg.

We found our toothpaste covered egg stained less than the non toothpaste covered egg.

The vinegar completely dissolved the eggshell, leaving just the membrane behind.

Why do teeth stain?

Tea is rich in tannins which stain teeth if they’re not cleaned properly while cola and fizzy drinks are acidic as well as containing staining products.

Vinegar ( which is acidic) dissolves the calcium carbonate in the shell, leaving just the membrane intact. This very cool egg experiment lets you bounce an egg without it breaking!

Download the experiment instructions!

More egg experiments for kids

Walk on raw eggs like Housing a Forest.

Make a model mouth using biscuits, marshmallows, jam and peanut butter. This disgusting activity is one of 60 Gross Science Experiments you can find in my latest book, GROSS SCIENCE.

Or, how about trying one of my other very eggy experiments!!

Extra background information for KS1 and KS2 Science

Teeth are not just for eating, animals often use them to defend themselves or to attack other animals.

Different shaped teeth have different purposes. Flat molars like humans have are for grinding and chewing food, while sharp canine teeth are for tearing food apart ( these are found in carnivores ) and large incisors for cutting and chopping grass ( found in herbivores ).

Caring for teeth

Cleaning teeth, using floss and mouthwash help keep teeth and gums free from plaque. Plaque is formed by bacteria feeding on the sugar left on the surface of teeth after eating.

Suitable for Early Years Foundation Stage

Physical Development → Health and self-care → ELG

  • Children know the importance for good health of physical exercise, and a healthy diet, and talk about ways to keep healthy and safe. They manage their own basic hygiene and personal needs successfully, including dressing and going to the toilet independently.

Key Stage 2 – teeth test

Describe the importance for humans of exercise, eating the right amounts of different types of food, and hygiene.

Safety Notice

Science Sparks ( Wild Sparks Enterprises Ltd ) are not liable for the actions of activity of any person who uses the information in this resource or in any of the suggested further resources. Science Sparks assume no liability with regard to injuries or damage to property that may occur as a result of using the information and carrying out the practical activities contained in this resource or in any of the suggested further resources.

These activities are designed to be carried out by children working with a parent, guardian or other appropriate adult. The adult involved is fully responsible for ensuring that the activities are carried out safely.


Solution

You can reduce the impact of phosphoric acid on your teeth by changing the way you consume soda and other foods with this ingredient. Dentist Dan Peterson recommends drinking soda through a straw to minimize contact with your teeth, rinsing your mouth out with water after drinking soda, limiting your soda intake to one serving per day, and drinking phosphoric acid-containing beverages only at mealtime. In addition, drinking soda quickly rather than sipping it slowly can reduce the exposure phosphoric acid has with your teeth.


DO WEAK OR STRONG ACIDS REMOVE CARBONATE CONTAMINATION FROM ANCIENT TOOTH ENAMEL MORE EFFECTIVELY? THE EFFECT OF ACID PRETREATMENT ON RADIOCARBON AND δ 13 C ANALYSES

In hot environments, collagen, which is normally targeted when radiocarbon ( 14 C) dating bone, rapidly degrades. With little other skeletal material suitable for 14 C dating, it can be impossible to obtain dates directly on skeletal materials. A small amount of carbonate occurs in hydroxyapatite, the mineral phase of bone and tooth enamel, and has been used as an alternative to collagen. Unfortunately, the mineral phase is often heavily contaminated with exogenous carbonate causing 14 C dates to underestimate the true age of a sample. Although tooth enamel, with its larger, more stable crystals and lower porosity, is likely to be more robust to diagenesis than bone, little work has been undertaken to investigate how exogenous carbonate can be effectively removed prior to 14 C dating. Typically, acid is used to dissolve calcite and etch the surface of the enamel, but it is unclear which acid is most effective. This study repeats and extends earlier work using a wider range of samples and acids and chelating agents (hydrochloric, lactic, acetic and propionic acids, and EDTA). We find that weaker acids remove carbonate contaminants more effectively than stronger acids, and acetic acid is the most effective. However, accurate dates cannot always be obtained.


Tooth decay to be a thing of the past? Enzyme responsible for dental plaque sticking to teeth deciphered

The Groningen professors Bauke Dijkstra and Lubbert Dijkhuizen have deciphered the structure and functional mechanism of the glucansucrase enzyme that is responsible for dental plaque sticking to teeth. This knowledge will stimulate the identification of substances that inhibit the enzyme. Just add that substance to toothpaste, or even sweets, and caries will be a thing of the past.

The results of the research have been published this week in the journal Proceedings of the National Academy of Sciences (PNAS).

The University of Groningen researchers analysed glucansucrase from the lactic acid bacterium Lactobacillus reuteri, which is present in the human mouth and digestive tract. The bacteria use the glucansucrase enzyme to convert sugar from food into long, sticky sugar chains. They use this glue to attach themselves to tooth enamel. The main cause of tooth decay, the bacterium Streptococcus mutans, also uses this enzyme. Once attached to tooth enamel, these bacteria ferment sugars releasing acids that dissolve the calcium in teeth. This is how caries develops.

Three dimensional structure

Using protein crystallography, the researchers were able to elucidate the three dimensional (3D) structure of the enzyme. The Groningen researchers are the first to succeed in crystallizing glucansucrase. The crystal structure has revealed that the folding mechanism of the protein is unique. The various domains of the enzyme are not formed from a single, linear amino acid chain but from two parts that assemble via a U-shaped structure of the chain this is the first report on such a folding mechanism in the literature.

Functional mechanism

The unravelling of the 3D structure provided the researchers with detailed insight into the functional mechanism of the enzyme. The enzyme splits sucrose into fructose and glucose and then adds the glucose molecule to a growing sugar chain. Thus far the scientific community assumed that both processes were performed by different parts of the enzyme. However, the model created by the Groningen researchers has revealed that both activities occur in the same active site of the enzyme.

Dijkhuizen expects that specific inhibitors for the glucansucrase enzyme may help to prevent attachment of the bacteria to the tooth enamel. Information about the structure and functional mechanism of the enzyme is crucial for developing such inhibitors. Thus far, such research has not been successful, states Dijkhuizen: 'The various inhibitors studied not only blocked the glucansucrase, but also the digestive enzyme amylase in our saliva, which is needed to degrade starch.'

The crystal structure also provides an explanation for this double inhibition. The data published by the Groningen scientists shows that glucansucrase proteins most likely evolved from amylase enzymes that degrade starch. 'We already knew that the two enzymes were similar', says Dijkhuizen, 'but the crystal structure revealed that the active sites are virtually identical. Future inhibitors thus need to be directed towards very specific targets because both enzymes are evolutionary closely related.'

Toothpaste and sweets

Dijkhuizen points out that in future glucansucrase inhibitors may be added to toothpaste and mouthwash. 'But it may even be possible to add them to sweets', he suggests. 'An inhibitor might prevent that sugars released in the mouth cause damage.' However, Dijkhuizen doesn't expect that toothbrushes have had their day: 'it will always be necessary to clean your teeth.'

Story Source:

Materials provided by University of Groningen. Note: Content may be edited for style and length.


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 20 ml 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 mineral supplements to citric acid on enamel erosion

The aim of this study was to evaluate the effect of mineral supplements to citric acid (1% pH 2.21) on enamel erosion under controlled conditions in an artificial mouth. From each of 156 bovine incisors one polished enamel sample was prepared. The samples were divided among 13 experimental groups (n=12). In group 1 citric acid only was used (control). In groups 2–10 either calcium, phosphate or fluoride in various low concentrations was admixed to the citric acid. In groups 11–13 the citric acid was supplemented with a mixture of calcium, phosphate and fluoride. For demineralisation the specimens were rinsed with the respective solution for 1 min, immediately followed by a remineralisation period with artificial saliva (1 min). The specimens were cycled through this alternating procedure five times followed by rinsing for 8 h with artificial saliva. The de- and remineralisation cycle was repeated three times for each specimen interrupted by the 8 h-remineralisation periods. Before and after the experiments, the specimens were examined using microhardness testing (Knoop hardness) and laser profilometry. Hardness loss and enamel dissolution was significantly higher for the controls as compared to the remaining groups. Significantly lowest hardness loss for all groups was recorded for group 12 with admixture of calcium, phosphate and fluoride to citric acid. The significantly highest enamel loss was recorded for the controls compared to all other samples. Groups 3 and 4 revealed significantly lower and higher tissue loss compared to the remaining groups (2–13), respectively. The other groups did not differ significantly from each other.

Modification of citric acid with calcium, phosphate and fluoride exerts a significant protective potential with respect to dental erosion. However, with the low concentrations applied enamel dissolution could not be completely prevented.


What are the layers of a tooth?

Each of your teeth has several layers that protect the pulp deep inside the tooth. The pulp is made of living connective tissue that contains blood vessels and nerves. The blood vessels in the pulp supply the other layers of the tooth with minerals. The nerves send messages to the brain about temperature, pressure, and injuries to the tooth.

The layers that protect the pulp are the cementum, dentin and enamel. The cementum connects the tooth to the bones in your jaw. Surrounding the pulp is the dentin. The dentin forms the foundation for the outer enamel layer. Dentin is yellow and rates a 3 on the Mohs scale of hardness.

The outermost layer is the enamel. It’s the hardest substance in the human body! Enamel is mainly made up of a crystalline form of calcium phosphate (Ca10(PO4)6(OH)2). It is even harder than bone and rates a 5 on the Mohs scale.

Did You Know?

The enamel on your teeth is made up of 95% minerals. The rest is water and other organic materials.


Tooth decay: Take the acid test

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Most parents realise the importance of regular brushing to prevent tooth decay, but few are really aware of another serious and growing problem of dental hygiene. Tooth erosion caused by acidic food and drinks, and the resulting rise in the number of people suffering from sensitive teeth, is affecting an increasing proportion of the population. And it starts in childhood.

Anecdotal reports from dentists' surgeries suggest that tooth erosion resulting from the outer enamel being dissolved by acids in the mouth is an increasing problem. Data from the last survey of children's dental health, involving detailed examinations of more than 10,000 children, found a small but significant increase in erosion between 1993 and 2003. It also found that tooth erosion in the permanent – adult – teeth affects more children as they get older.

The mouth is a naturally non-acidic environment. Healthy saliva is neutral or slightly alkaline, which is at the opposite end of the spectrum to acidity. Acid and alkaline are measured on a logarithmic scale of "pH" running from 1, which is very acidic, to 14, which is intensely alkaline, with a pH of 7 being "neutral".

Saliva in a healthy mouth is about pH 7.4. However, some carbonated soft drinks have a pH as low as 3.4, making them highly acidic from a biological perspective. Acids erode the surface of teeth, which are essentially composed of calcium salts that are highly vulnerable to acidic attack. Indeed, if a tooth is dropped into a glass of fizzy drink, the enamel will eventually dissolve.

Tooth erosion can also have other causes. Nearly one in 10 people for instance suffer from gastro-oesophageal reflux, when the natural acids in the stomach flow up to the mouth. These stomach acids tend to erode the back teeth more than those at the front. Frequent vomiting associated with eating disorders and even over-brushing with abrasive toothpastes can also cause surface wear and erosion of the outer enamel that protects the tooth.

One of the common outcomes of erosion is painfully sensitive teeth. The thinning of the enamel begins to expose the inner, softer layer of dentine. One of the features of dentine is that it has microscopic channels or tubules that radiate out from the central pulp core to the outer enamel. It is these tubules that allow differences in temperature or sweetness to pass directly to the nerve, causing the sensation of pain.

"When teeth are alive they have pulp tissue inside, often called 'the nerve'. This is like any other living part of the body, with blood vessels, cells and nerves which penetrate into the dentine," says Keith Cohen, based at Dentexel, a practice in London, and one of the capital's best restorative dentists. "When a patient suffers from erosion, there is a gradual loss of enamel, exposing the dentine. Consequently, there is less protection of the nerve tissue and opening of the dentine tubules, resulting in sensitivity to various stimuli such as cold and hot, brushing, and foods that are erosive or sweet," he explains.

Dentists recognise two important causes of what they call "tooth-surface loss".

One is the chemical erosion of the surface by such things as dietary acids. This is quite different from the erosion caused by tooth decay resulting from the bacteria responsible for dental caries. Another major cause of dental erosion is physical wear, either resulting from to tooth-to-tooth "grinding" contact, or due to abrasion, such as from vigorous tooth brushing.

Tony Smith, professor of oral biology at The University of Birmingham, points out that these different elements can sometimes interact with devastating consequences. For instance, it is now well established that brushing the teeth soon after drinking an acidic drink, such as a fruit juice in the morning, can have a far more detrimental impact in terms of loss of enamel than either activity has on its own.

"An acidic drink can pre-soften the enamel and make it more susceptible to being abraded away as a result of heavy brushing. It can take up to 20 minutes for the surface of a tooth to get back to normal pH after an acidic drink. I advise people to wait 40 minutes or an hour after having acidic food or drinks before they brush their teeth," Professor Smith says.

This is why it's a good idea to brush your teeth in the morning before having a fruit juice for breakfast. It lowers the risk that chemical erosion and physical abrasion can work together to rub away the protective enamel surface.

Professor Smith says it is difficult to quantify the scale of dental erosion in the population and to gauge just how much worse the situation may be getting.

To do that, it would be necessary to monitor and examine a large group of children and young adults over many years, or have very large, regular surveys of the general population involving many thousands of people.

The dental health survey of children in 2003 from a wide mix of social backgrounds found that tooth surface loss on the "lingual" side of teeth (next to the tongue) of 12-year-olds increased from about 21 or 22 per cent in 1993 to about 24 or 26 per cent in 2003. For the buccal (next to the cheek) side, the respective increase was from about 6 or 8 per cent to 8 or 10 per cent. For 15-year-olds, the situation was worse, with lingual-surface erosion growing from 23 per cent in 2003 to about 26 or 28 per cent in 2003.

So it seems that tooth erosion has over the past 10 years has become more of a problem judging by this limited survey. It also gets worse as children get older, as the data on 15-year-olds show.

The fact that the inner, lingual side of the tooth is hit hardest also suggests that the cause could be chemical erosion rather than over brushing, although tongue movements across the softened tooth surface may also exacerbate the wear on this side of the tooth, according to Professor Smith.

One possible cultural explanation for the rise in tooth erosion is the move away in recent years from selling soft drinks in cans to serving them in plastic bottles with screw tops. This has encouraged the adolescent habit of sipping drinks throughout the day.

Professor Smith points out that children today are more likely to be taking constant swigs from a plastic bottle of fizzy drink rather than gulping the whole thing in one go (as they are more likely to do with a canned drink). "A bottle with a screw-top allows someone to carry it around with them and drink more slowly, constantly topping up the acidity of the mouth. The surface of the teeth keeps acidic for longer periods," Professor Smith says.

Whereas classical dental practice has in the past been directed at treating decay caused by dental caries, the modern problem of tooth erosion is more difficult to treat because it affects the entire surface of a tooth. Drilling and filling a tooth cavity is relatively easier to deal with than treating the entire surface of a tooth.

Cohen says that the first stage in treatment is to identify the cause of the problem – whether it is dietary or an underlying medical problem. He says that sugar-free chewing gum, which increases the flow of saliva, can help, as can finishing a meal with cheese or milk, which can neutralise salivary acid.

Sensitive teeth can be treated with high- fluoride toothpaste or remineralising pastes containing calcium and phosphate. Colgate, for instance, has recently released a desensitising toothpaste containing the amino-acid arginine and an insoluble calcium agent, which is "clinically proven" to fill the microscopic channels in the dentine that transmit painful stimuli in sensitive teeth.

Colgate reckons that hypersensitivity affects more than half of all dental patients worldwide and that its toothpaste poses a radical solution in that it literally plugs the problem, rather than simply treating the symptoms by numbing the pain of sensitive teeth, as other brands of toothpaste try to do.

But if the erosive damage is already done, restorative dentistry may be the only option. Cohen says that the treatments include: crowns, where the entire top of the tooth is reduced by about 1 millimetre and replaced with an artificial tooth veneers, where the one surface, usually the front, is replaced by an artificial coating tailor-made in the lab for each patient and composite coverings applied in the surgery. These last are cheaper than veneers and more easily repaired and modified, but can only be reliably dealt with by highly skilled professionals.

All of these solutions have their own drawbacks. Crowns, for instance, rely on a good tooth structure to act as a peg, and expensive veneers, which are good aesthetically, can work loose and chip. Composite coverings can stain if someone smokes or drinks lots of strong tea or red wine and may have a shorter lifetime than veneers or crowns. But none of them comes cheap.

The only real solutions to dental erosion are prevention and the avoidance of frequent contact between the teeth and acidic drinks and foods. That also means recognising the problem early enough in life to make sure it doesn't happen – which can be quite difficult when sipping fizzy drinks from plastic bottles is such a popular pastime among children and adolescents.

How to protect your teeth

* Drinks to avoid are fizzy, carbonated drinks, especially the colas (which contain phosphoric acid), pure fruit juice, and some alcoholic drinks, eg white wine and cider. Sparkling mineral water has minimal erosive effect.

* Foods to go easy on include fruits, especially citrus, grapes and sour apples. Beware also of sauces such as ketchup and brown sauce, and snack foods such as salt and vinegar crisps, and pickled foods.

* Avoid sipping continually from bottles containing carbonated drinks. It's better to drink them in one go.

* Don't brush your teeth immediately after drinking a fizzy drink or a fruit juice. Wait for at least 40 minutes or an hour.

* Do not over-brush teeth, especially with abrasive, whitening toothpastes.

* Seek medical advice for gastric problems that could increase oral acidity, such as reflux.