​Are some people really born with soft teeth?

Yes. There are certain medical conditions in which the enamel or hard outer covering of the tooth fails to form properly (like ameliogenisis imperfecta) but fortunately, these are relatively rare.

What is more common is a complex relationship between genetics, diet, and oral heath that determines how easily you get decay.

Lets start today with genetics. Your genetics will determine things like the thickness of enamel (the protective shell) , tooth shape, and position, saliva flow and composition, the ability to buffer acid, and the shape of your jaw.

Lets see how each of these makes a difference:

Enamel thickness and hardness

Decay happens when naturally occurring bacteria in the mouth feed on sugars and starches to produce acid. This acid eats away at the enamel, eroding it until a hole or ‘cavity’ is made in the tooth. If the enamel is thicker or more acid resistant, then it will take more time for the acid to penetrate the soft inner part of the tooth known as dentin.

One of the ways to make enamel stronger or more acid resistant, is through the use of fluoride. If fluoride is available when the tooth is developing in the jaw, the body will naturally incorporate it into the tooth making it more acid resistant.  Calcium absorption (and vitamin D) is important too. On the other hand, certain drugs or a high fever can cause interference with enamel development, weakening the tooth before it has even erupted.

Groovy Teeth

Genetics will also influence how you teeth are shaped . In general, the smoother the teeth, the more self cleansing they are and the less likely they are to decay. Decay likes to start in the hard to reach areas like deep grooves or between the teeth.  Often, teeth with deep grooves will have areas that are unprotected by enamel. That’s why you can even get decay starting before a tooth has erupted. Bacteria loves tiny crevices where it can grow undisturbed.

(Sealants and small fillings work by covering areas that don’t have enough enamel and making a smother, easier to clean surface)

Straight teeth

Straight teeth tend to get less decay because they are easier to clean and catch less food.


The tongue, cheeks, and saliva work as a tiny tooth washing machine all day long. In the night, salivary flow decreases so teeth have less protection against bacteria growth. Saliva has enzymes for breaking down sugars, antibodies to attack bacteria, and most importantly, buffers which counteract the effects of acid. The consistency and amount of saliva will depend on genetics but also on things like diet, hormone levels (pregnacy), medications, age, and hydration.

Crowded teeth, acid reflux, sleep apnea and other breathing problems

It may seem strange to put these together, but they can be linked. If the airway is blocked by large tonsils or adenoids, then the body will switch from nose breathing to mouth breathing. Often this is most noticeable at night because the tissues and become more flacid (soft and floppy). But in more severe cases, the mouth will be held slightly open all day. For adults this means the tongue and saliva have a hard time keeping the teeth bathed in protective saliva and so we can see an increase in cavities. In some cases, when  the airway is very obstructed, pressure builds up in the diaphragm and this pressure can cause some of the acid in the stomach to leak out into the esophagus (throat) and then into the mouth, creating an acid bath for the teeth. Grinding and clenching are often seen in people with sleep airway issues. Grinding helps open up the airway. (More on grinding when we talk about jaw shape)
Acid reflux during the day can also result in a particular pattern of tooth decay. Pregnancy, diet, medications and genetics can increase your susceptibility to acid reflux.

Children will overly large adenoids and tonsils will tend to have narrow palates (upper jaws and wider lower jaws) . The is because part of the tongues job is to balance the forces created by the cheeks. The cheeks and lips push the teeth inward and the tongue, an incredibly strong muscle, pushes the teeth outward. With out the tongue to push outwards, the upper jaw becomes narrow or pinched and the sinus cavity above it fails to develop fully either.  It is truly amazing to see how the removal of adenoids in these children  allows the teeth and jaw to spontaneously correct itself. So, if you are worried about airway issues with your child , please let us know.

Jaw shape (Grinding and Clenching)

Its estimated that about 90 percent of people will grind their teeth at one time or another. We’ve seen earlier that airway can affect grinding habits. Stress is an important component and we often see an increase in teen patients reporting jaw pain right around exam time. But for some people, grinding is just a natural every day function of the central nervous system (and this is probably genetic). Grinding causes wear to the teeth, so that the enamel is thinned (like a lathe or sander running back and forth). Clenching causes tiny cracks in the enamel like a rock chip in your windshield. Some of these chips are harmless, but others propagate and damage the structure of the tooth, creating tiny entry points for bacteria to enter inside. The shape of your jaw can also determine how much leverage or force you can put on your teeth. So, square jaws tend to generate heavier forces then tapered jaws.

The good news is that once we identify the reason for tooth decay, together then we can start to eliminate those reasons and that’s when prevention is its most effective.

Braeside Dental Centre


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