Dental caries, or “cavities”, are the result of dental decay. Dental decay is the destruction of your tooth’s structure by bacteria normally found in your mouth.  The bacteria convert sugar, from the food you eat, into acid that slowly degrades your tooth, weakening it, and eventually creating holes that are termed “cavities”.

Dental decay is an infection that can spread. This fact is often lost among the general public. If nothing is done in terms of treatment and prevention, bacteria will spread from one tooth to another, causing decay in several teeth.

The role of dentists is two-fold: first, to patch up the decayed tooth, but more importantly, to inform you on how to prevent future tooth decay.
 

A diagram depicting dental decay (top), and a real-world example (below).  Note that some teeth may just be stained - darkened pits do not always equate to dental decay.

What causes tooth decay?

Through regular use, our teeth get covered with a sticky film of bacteria called plaque. The bacteria found in plaque is normally harmless to our teeth, but combined with sugar or starch found in our foods, they become pathogenic and can cause decay. They convert the sugar and starch into acids that can attack tooth enamel – this is termed an "acid attack". Repeated “acid attacks” may eventually result in dental decay.

Who is at risk?

For decay to occur, bacteria, and the sugar they feast on, both need to be present. Individuals with poor oral hygiene often present with high bacterial counts – placing them at risk. Similarly, so are those who regularly consume sugar or starch filled foods.

While anyone with poor oral hygiene and diet can acquire “cavities”, there is a subset of people who are at the greatest risk.  For example, children’s teeth are less mineralized than those of adults, making them susceptible to decay. Many people mistakenly think that cavities are only a childhood concern, but in reality, the changes that occur with aging place adults at risk as well. With age, gums begin pulling away from the teeth, or “receding”, and this can leave tooth roots exposed and open to decay.

A highly magnified electron microscope picture of a dental filling in a tooth. Note the unpreventable gap between the filling and the tooth - bacteria can gain access through this and cause decay underneath.

Those with previous dental fillings are at risk of dental decay as well. Decay can form around the edges of fillings, no matter how well they are constructed. Also, anyone who grew up without the benefits of having fluoride added to the municipal drinking water is at risk.

To recount, the following people are at greatest risk for “cavities”:

• anyone with poor oral hygiene (infrequent brushing or flossing)
   

• anyone with poor diet (high sugar and starch consumption)
   

• children with some, or all, of their primary (baby) teeth remaining
   

• aging adults with receding gums and exposed tooth roots
   

• any tooth that already has a filling or restoration
   

• anyone who did not drink fluoridated water while growing up

There are a host of other factors that play a role, but these are the most significant.

What are some symptoms?

Initially, you might not even be aware you have a decaying tooth. As time progresses, the decay will extend deeper into the tooth, and that is when the following symptoms may appear:

• hot/cold/touch sensitivity

• toothache

• fracture of the tooth

• abscess formation

If matters persist, and no treatment is provided, the tooth will most likely be lost or need extraction.

How do dentists diagnose tooth decay?

X-Ray film with identification arrows pointing out the dental decay in the upper left premolar. X-Rays are not always necessary for identifying decay.

During your regular dental checkup, your dentist will identify if you have any tooth decay by first asking questions about your past dental care and hygiene to see if you are a high risk patient.

Next, your dentist will examine your teeth using a pointed device called an “explorer” and a small hand-held mirror. Finally, to confirm any suspected decay, your dentist may rely on dental x-rays.

The entire process is painless and fairly quick.

What treatments are available for dental decay?

Treatment largely depends on your age, and the extent of damage/decay. For children, if a primary (baby) tooth that is already loose becomes decayed, your dentist may simply pull the tooth out. This does not mean that baby teeth are expendable – they are not, as is discussed later. Nonetheless, common sense dictates that under certain circumstances, it makes more sense to pull a tooth than try in vain to save it.

For adults, your dentist is likely to try in every way to save your decayed tooth. For simple surface decay that is caught earlier and has not gone past the tooth’s enamel layer, a dental filling is not necessary. Simply changing your oral hygiene and diet habits, with the addition of fluoride treatments, is enough to help restore the tooth to sound health.

If the decay has gone in deeper, to the point that it is no reversible, your dentist will likely provide you with a dental filling. If the decay has destroyed a large portion of the tooth, a filling might not hold in place, and a dental crown will be necessary. If the bacteria have penetrated the inner pulp of the tooth, a root canal treatment is required.

Finally, if the bacterial infection has gone past the pulp, and spread through the tooth’s roots to the underlining bone, forming an abscess, the tooth may need to be extracted.

Clearly, the extent of damage varies greatly, as do the possible treatments. Fortunately, dental decay progresses relatively slowly, in the order of months or years, with the exception of rampant caries such as Early Childhood Caries. If you see your dentist regularly, he or she will likely catch any decay at an early stage, before it becomes a more costly issue.

How do I prevent dental decay?

The best form of treatment is prevention. No matter what your dentist claims, a dental filling will never restore a tooth to its original form. Preventing dental decay comes down to four essential things: brush your teeth regularly, floss regularly, eat a healthy diet, and do not smoke!

Read more on how to maintain good oral health, here.

Should my child’s baby teeth be treated?

Far too many parents are unaware of the importance of primary (baby) teeth. This misconception comes from the fact that baby teeth are temporary. Many people therefore assume that the primary teeth are not as important as the permanent teeth.

Baby teeth need treatment! Here are just a few of the roles baby teeth play:

• they are used for chewing which helps develop the bones and muscles of the face, as well as aiding in proper nutrition
   

• they give the child a nice appearance and smile which is important for their social acceptance and psychological development
   

• they aid in the learning of speech
  

• they maintain space for the permanent teeth to grow into

·    Furthermore, decayed baby teeth can even infect and damage the permanent teeth developing below them. Sometimes, dentists will remove (extract) baby teeth instead of treating the decay – this should be left to the dentist’s discretion. As a parent, you should never assume your child’s baby teeth are expendable and do not require treatment.

Early Childhood Caries or “Nursing Caries”

As soon as a baby's first teeth appear—usually by age six months or so —the child is susceptible to decay. This condition is often referred to as Baby Bottle Tooth Decay or Early Childhood Caries (cavities). In some unfortunate cases, infants and toddlers have experienced severe tooth decay that has resulted in dental restorations or extractions. The good news is that decay is preventable.

To learn more, visit our page dedicated to the topic of Early Childhood Caries.