What are Cavities and How to Prevent them: Part 1 Tooth decay is still a disease that affects humans and it is likely to be with us for the foreseeable future.
In my dental practise I have patients that have never developed a cavity while others are cavity prone.
In this article I will give an overview of how cavities form and ways to prevent cavities. Before we jump in consider a few interesting facts:
Our teeth are covered by an outer protective layer, enamel. Enamel is the hardest substance in the human body. Enamel is harder than bone yet our teeth is the only part of our body that rots.
Once we die our teeth are indestructible. Google this article: “French archaeology students find 560,000-year-old tooth.”
However during our lives our teeth are anything but indestructible.
Above the gumline our teeth are covered by hard enamel. Under the enamel is a softer layer called dentin which is about as hard as bone.
Our teeth are composed of mainly the minerals calcium and phosphate.
Enamel can be dissolved by acid found in certain foods and drinks and by acid produced by bacteria that cling to our teeth.
The decay process
Our mouths are full of bacteria. Some of these types of bacteria cause tooth decay (cavities). We call the coating of bacteria on our teeth plaque.
Plaque develops in deep grooves and pits in, in between the teeth where a toothbrush doesn’t reach as well as along the gum line.
Some types of bacteria/plaque convert in sugar and starches from food and drink we consume into acid.
If the acid remains on your tooth too long it will the dissolve the calcium and phosphate in the enamel. This will cause the enamel to appear white and chalky. This loss of calcium and phosphate is called demineralization. If the white spot on a tooth does not regain the calcium and phosphate and the enamel continues to be dissolved by acid produced by bacterial plaque, the white spot will progress beyond the point of no return and become a cavity. These white spots in teeth can be reversed.
How to rebuild enamel or repair a white spot:
1. Reduce the amount of plaque on the tooth (better brushing/flossing)
2. Re-exposing the tooth to calcium and phosphate can reharden the enamel . The white spot will harden and the enamel will return to its normal appearance. This is called remineralization.
Later I will explain how dentists can help you remineralize or repair white spots forming on your teeth.
Note: Cavities that develop in the grooves and pits of teeth may appear brown or dark. They will not start as white spots. More on this later.
Caries is another word for cavities. In the above diagram the "white spot" has progressed to become a dark cavity. If untreated decay starting in the enamel progresses into the dentin and then into the root canal of the tooth.
ow to prevent cavities:
1. Brush well, 2-3 times a day. Floss once a day. If you leave plaque on your teeth you are increasing the chance of getting a cavity. Keep a toothbrush and toothpaste at the office.
2. The bacteria in plaque not only feed on sugar; they also can feed on carbohydrates found in bread, crackers, cookies, pretzels and potato chips.
So it is not only candy that causes cavities. If cookies or bread lodges in the pits or grooves of your teeth or in between your teeth the starches in those foods can be converted into acid by the plaque on your teeth. (Another reason to floss daily)
3. Brushing after a sugary or starchy snack or chewing a piece of sugarless gum after such a snack can stimulate saliva and wash the sugars and starches off our teeth.
4. Nuts and seeds do not contain sugars/carbohydrates that fuel acid production on your teeth so choosing them as a snack over chips or candies can reduce cavities.
5. Fresh fruit does contain natural sugars but the sugars are bound up in fibre and are less easily accessed by bacterial plaque so are less likely to cause decay .
6. Eating too much dried fruit can lead to cavities. Dried fruit such as raisins are sticky and soft. Their residue can cling to our teeth, allowing plque/bacteria to feed on their sugar content increasing risk of decay.
Acidic Drinks Can Promote Decay and Damage Enamel
If you consume acidic food or drink the surface of your tooth becomes acidic. The bacteria on our teeth grow in number in number in the presence of acid and reduce heir numbers if your mouth is not acidic.
If you consume acidic food/drink often this promotes the growth of the bacteria that causes cavities.
As well, enamel and dentin will gradually wear down due acid erosion if exposed to excessive acidic foods or drink. This will result in a thinning of the enamel.
What determines if your mouth is acidic or not?
The acidity of any food or drink can be measured. Iced tea and lemonade are examples of two drinks that are acidic.
Acidic drinks,like lemonade and iced tea for example, make plaque/bacteria more abundant for the reason that bacteria function better if surrounded by acid.
The chart below shows the amount of acidity of some common foods and drinks and other substances.
Any foods on the left hand side of the chart are acidic and support bacterial growth in the mouth and overconsumption can erode enamel/dentin.
As seen on the chart our enamel will start to dissolve if exposed to liquids that are a pH of 5.5 or less (enamel demineralization)
From the pH chart some points to consider:
Citrus juices or fruits such as orange, lemonade, grapefruit juice and most soft drinks (i.e.Colas, Root Beer, Mountain Dew) are acidic drinks and have a pH value in the 2 to 3 range. These drinks can dissolve enamel and promote the growth of cavity causing bacteria. Lemon in water will promote enamel erosion if sipped for extended periods of time.
If you check the label of your favourite soft drink/soda you will see citric, carbonic and/or or phosphoric acid. - Carbonic acid results from the carbonatation or adding bubbles to the soft drink. - Phosphoric acid is added to some soft drinks as a preservative. - a flavouring agent
Tea and coffee have a pH of 2 to 3 and also provide an environment that supports cavity causing bacteria and tooth demineralization.
Exposing your teeth to sugars and/or or acidic drinks many times during the day or for long durations can cause cavities.
Here are a few examples. Cavity problems can arise if:
- you carry around a bottle of juice, pop or an energy drink and takes sips from it during the day
- you have a morning coffee or tea with a teaspoon of sugar but sip on it for an hour or more hour each morning
- you have 2 or 3 coffees a day with sugar and it takes you 3o minutes or more to drink each coffee.
These are just a few examples of dietary habits I hear from patients who run into cavity problems.
In these cases: - the mouth is acidic for long stretches of time - the bacteria on the teeth are getting a constant supply of sugar. - this leads to a continual production of acid that sits on the teeth and cavities result.
Our saliva has the ability to bathe damaged enamel and dentin in calcium and phosphorous, that is, the tooth surface can be repaired and rebuilt. This is called remineralization.
If the tooth has periods of time when it is not being bathed in cola or juice or exposed to candy or starches the tooth surface can have a chance to remineralize.
These minerals can be deposited back into the injured enamel/dentin and the tooth can harden or remineralize. Fluoride can also help remineralize a softened, demineralized tooth.
Sticky candy like gummy bears or sour keys or long lasting candy such as lollipops also expose the teeth to a longer sugar and acid attack, which can overwhelm the ability of the tooth to repair and rebuild.
4. Dry mouth and cavities
People who have chronically dry mouths are at a very high risk for developing cavities. Saliva washes bacteria off our teeth, and buffers our teeth (makes them less acidic) and delivers calcium and phosphorous to help rebuild demineralized enamel and tooth structure.
If you do not produce enough saliva you will get:
More bacteria buildup on your teeth due to less washing of saliva.
And less rebuilding of damaged tooth as fewer minerals are being delivered to damaged tooth structure
Dental disaster strikes in patients with dry mouth who make the unfortunate choice of sucking on candies that contain sugar to keep the mouth moist or who sip on pop, juice, coffee or tea with sugar to keep the mouth lubricated.
The patient with dry mouth already has more plaque or bacteria on their teeth. The sugar will cause decay, the pop or juice provides an acidic environment in the dry mouth and the result can be devastating.
I have seen patients with dry mouth issues develop cavities in many of their teeth, under fillings and under other kinds of dental work.
Some Good News About Cavities
The good news is that cavities are not inevitable and our goal in dentistry is to prevent cavities from developing, repairing ones that start and also allow you to eat foods you enjoy without destroying your teeth.
It's about keeping the amount of acid your teeth are exposed to to a reasonable level and also promoting remineralization.
So here are some tips to prevent cavities based on our discussion above:
Limit acidic drinks (soft drinks, citrus juices) to meal times and limit the amount you drink.
If you are going to have acidic foods, sweets or other cavity causing carbs limit them to when you are eating breakfast, lunch or dinner; try not to have these cavity causing/demineralizing foods spread over many small meals and / or snacks throughout the day. This allows your mouth and tooth surface to recover from the acidic conditions created by the acidic foods or drinks.
Milk is a better choice than soft drinks/soda and citrus juices as it is not as acidic but you should limit milk to snack time or meal time and do not sip on it for hours at a time as milk does contain natural sugars that promote cavitities.
If you must drink juice, dilute it with water. You may not like it at first but once you get use to it you won’t even notice the difference in taste. At least that has been my personal experience.. I dilute my orange juice: one part orange to three or more parts water. This is less acidic and less sweet. Fewer calories as well. It is an acquired taste but if I can get used to it you likely can too.
Avoid soft drinks/soda, again for the reason that pop/soft drinks/soda contain acids and sugar. Diet soft drinks do not contain sugar but they do contain acid.
If you like to carry a drink with you to sip at during the day tap water is best….it is fluoridated and is neutral i.e. is not acidic.
Whereas, believe it or not some brands of bottled water are actually acidic. There are some brands of bottled water that have a pH in the range of 3.5 to 5.0 ; remember: enamel demineralizes at a pH of 5.6
If you are a bottled water fan search the name of the bottled water you normally like to drink online and check the acidity/pH of that brand. You may be surprised to see the amount of acidity of certain brands of bottled water.
Limit sweets and avoid the sticky ones (i.e. caramels, toffees,fruit roll ups) and definitely no lollipops (unless they are sugar-free)
Dr. Jeff Shnall is a dentist providing general, cosmetic and implant dentistry in the Beach neighbourhood of Toronto. For an appointment please either email us at BeechDental@gmail.com or call our office at 416-691-2886.