What are Cavities and How to Prevent them Part 1

• 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 are the only part of our body that rots or decays.
• 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.​

ewqeqe

Our Teeth

• The portion of our teeth (visible when you smile,above the gumline) is covered by hard enamel. 

• Under the enamel is a softer layer called dentin which is about as hard as bone.
• Our teeth (enamel and dentin) 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 (How Cavities are Formed)

• Our mouths are full of many different types of bacteria.  
• Some of these types of bacteria cause tooth decay (cavities). 
• We call the coating of bacteria on our teeth plaque.
• Plaque accumulates  in deep grooves and pits in our teeth and als0  in between the teeth where a toothbrush doesn’t reach, as well as along the gum line. 
• Some types  of  bacteria/plaque convert  sugar and starches from food and drink we consume into acid. 

• If the acid  remains on a 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.  
• White spots  on teeth can rebuild their  the calcium and phosphate and reharden. 
• However if the enamel does not rebuild lost calcium and phophate and  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. 

How to rebuild enamel or repair a white spot:

• Reduce the amount of plaque on the tooth (better brushing/flossing)
•  Re-exposing  the tooth to calcium and phosphate can re-harden 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 (grey are in the diagram above) and then into the root canal of the toot

How to prevent cavities: 

• 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 

• 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)
• 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.
•  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.
•  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.
•  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  plaque/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.
• Examples of acidic drinks:  Soft drinks/pop/soda, lemon water, fruit juices such as orange juice, grapefruit juice, some brands of sports drinks
• ​The bacteria on our teeth grow in number in number in the presence of acid and reduce their numbers if your mouth is not acidic.​
• So 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 and reproduce in greater numbers 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.

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 sugar and sip on it for long periods of time each morning
• You  have 2 or 3 coffees a day with sugar and it takes you 30 minutes or more to drink each coffee.  

hese are just a few examples of dietary habits I hear from patients who run into cavity problems.

What Promotes Remineralization of Our Teeth?

• Our saliva can  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.​​

 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 our teeth 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 and the pop or juice provides an acidic environment in the dry mouth, causing bacteria to thrive further,  and the results 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 or else your teeth will stay acidic, promoting cavity formation.
• This allows your mouth and tooth surfaces 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

• Milk is not as acidic but you should limit milk to snack time or meal time;
• Do  not sip milk  for hours at a time as milk does contain natural sugars that promote cavities.

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
• But tap water is a healthier choice than juice, and fresh fruit is a better way to get nutrients than juice (more fibre, less sugar 
• 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.
• Believe it or not some brands of bottled water are actually acidic.  
•  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 drink bottled water search the brand the bottled water online and check the acidity/pH of that brand.  You may be surprised

Limit sweets and avoid the sticky ones

• (i.e. caramels, toffees,fruit roll ups) and definitely no lollipops (unless they are sugar-free)

Choose healthy snacks:  nuts,  seeds, fruit, cheese.

​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.