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The 5 Stages of Tooth Decay & Treatment

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Dr Teresa Li
May 3, 2024

Tooth decay a common cause of a toothache and an unexpected trip to the dentists.  In this post, I’ll explain the five stages of dental decay and how to it can be treated at each step.

What is tooth decay?

Tooth decay is a progressive process where acid forming bacteria weaken the surface of a tooth.  The acid causes a small hole in the tooth, called a cavity.  Bacteria enter the inside of your tooth through this hole creating an infection.

The first stages are painless, so you won’t know you have early tooth decay.  That’s where regular dental visits come in giving your dentist a chance to spot early signs and stop the rot before it gets out of hand.

Causes of Tooth Decay

Several factors can lead to decay and tooth cavities including a diet rich in sugar and carbohydrates, sugary soft drinks, bottled water (without fluoride) and not sticking to regular brushing and flossing.  For some, medical conditions and even medications contribute to tooth decay.

Tooth decay starts in the enamel, especially in areas where plaque accumulates like the top surface that has crevices and between the teeth.

But how does plaque get on our teeth?

When the foods we eat are left on the teeth frequently, and for long periods the bacteria that live in the mouth will feast on these remnants of food and produce acid.   With time, the acid weakens the enamel.

The worst foods are carbohydrate based sugars and starches, foods like milk, soft drinks, cakes, sweets, fruit juice, dried fruit and so on.

The best way to prevent cavities and dental decay is still the action of brushing and flossing away food remnants, twice daily.  It gives less chance for the bacteria in our mouth to produce the plaque causing acid.  Of course, it’s also important to reduce sugary, carbohydrate-based foods.

Tooth decay a common problem

Sadly, tooth decay is a universal human ailment, and it affects young and old.

In children under the age of 6, nearly half of them have tooth decay in their baby teeth.  At least one in ten Australian children have an adult tooth with untreated decay according to one 2015 study.

Australian adults (15 years and over) on average have nearly eight tooth fillings as a result of tooth decay.

What Are The Five Stages of Tooth Decay?

First, let’s cover the different layers of a tooth to understand how tooth decay damages each.

A tooth has three layers: enamel, dentine & pulp.

Enamel: The outer part of a tooth that you see above your gums.  It is the hardest substance in the human body.  Its job is to protect the softer more sensitive inside of the tooth.

Dentine: The yellow layer below the enamel.  Dentine is softer and more porous than enamel with lots of tiny tubes that lead to the inside of the tooth.

Pulp: The innermost layer.  The pulp is the soft centre containing nerve tissue and blood vessels.

Stage One Tooth Decay: Enamel Lesion

As strong as our tooth enamel is (it’s the hardest substance in the human body!) it’s not indestructible and under the right conditions, bacteria can get the better of it.

The first stage is the formation of a small brown or white lesion on the enamel.  This lesion proceeds a cavity or hole in your tooth.  It won’t be visible on an x-ray, but a trained dentist will know what to look for.

Is an enamel lesion painful?

No.  The enamel is not susceptible to pain as there aren’t any blood vessels or nerves to signal pain to your brain.  It can also be difficult for you to see, especially on the back teeth.  Your dentist will most likely use a tiny camera to get close up shots of your tooth.

Dentist scanning patients mouth with camera
With the help of a tiny camera, your dentist will be able to spot enamel lesions

How can your dentist fix an enamel lesion?

Caught early enough it may be possible to reverse the lesion or at least stop it from getting worse.

Your dentist may use fluoride, cleaning treatments or a dental sealant to protect the tooth from further damage.  They’ll also give you a personalised home oral hygiene to keep the dental drill at bay.

It’s for this reason that the Australian Dental Association recommends six monthly dental check-ups.  This approach is called preventative dentistry, a philosophy we live and breathe at TL Dental in Port Macquarie.  It means fewer chances of more treatment and costs down the track.

Second Stage: Enamel Decay

In the second stage, the enamel is damaged creating a cavity or hole in your tooth; it’s no longer a superficial lesion.  At this stage, the damage is visible in an x-ray and will give your dentist an indication of how deep the cavity is.

Is enamel decay painful?

It depends.  If the hole is still only in the enamel, you are not likely to feel anything.  If the cavity is deep and close to the dentine, you may have some tooth sensitivity.

How can your dentist fix enamel decay?

Even though you might not feel any pain or discomfort at this stage, it won’t be possible to reverse the tooth cavity.  The body is not able to regrow tooth enamel.

The most common way to stop the tooth decay working its way into the soft dentine layer is to carefully drill out the decay and place a tooth coloured filling to make your tooth whole again.  This is one of the most common dental procedures.  It’s a safe, predictable and inexpensive way to fix a cavity.

Third Stage: Dentine Decay

Ok, so what happens if you don’t catch the enamel decay?

You guessed it; the bacteria works its way to the dentine.  Now it gets trickier as dentine is porous.  It’s more sponge-like, so from here bacteria will spread quickly.  At this stage, time is not on your side, and quick action is needed.

Is dentine decay painful?

Yes.  You will feel tooth sensitivity, slight toothache or discomfort.  At least your tooth will feel sensitive to hot and cold food and drinks.  The pain level will depend on your pain threshold and the spread of the dentine decay.

How can your dentist fix dentine decay?

To stop the decay, your dentist will need to remove the damaged part of the tooth.  Depending on the tooth and the amount of tooth structure they need to remove you may need a filling, a dental crown or an onlay/inlay to make the tooth whole and healthy again.

Fourth stage: Pulp Decay

If the bacteria spreads to the soft inside of the tooth, you will get what’s referred to as a  root canal infection.

Is pulp decay painful?

Yes, you will be in significant pain.  Blood vessels, nerves and connective tissue richly supply the inside of your teeth making the pulp sensitive.

How can your dentist fix pulp decay?

To stop your pain and clear the infection it is likely your dentist will do root canal treatment.  This is a delicate treatment that involves removing the infected pulp from inside the tooth, cleaning the canals thoroughly and filling them with a special dental material.  Depending on the tooth a dental crown may then be used to cap the tooth and make it strong again for chewing.

Stage Five: Formation of an Abscess

Left untreated this infection can result in a dental abscess (pocket with pus) at the tooth root. This abscess won’t go away on its own and you need to see a dentist without delay. The bacteria inside the tooth can spread to your jaw bone, ear and neck on the affected side, in some cases it can go to the brain making it very serious.

Is a tooth abscess painful?

Yes, this is excruciating.  You will feel an intense, throbbing pain in your tooth, gums and jaw.  Sleep will be difficult as the pain is worse when you lie down.  You will also likely have swelling, fever and an unpleasant taste in your mouth.

Even if you don’t have all of these symptoms don’t delay getting help.  Many people are shocked to learn that deaths have occurred when a tooth infection spreads to the brain and throat making it difficult to swallow or breathe.

How can your dentist fix an abscess?

Your dentist will need to take x-rays and assess the extent of the infection.  Sometimes the tooth can be saved with root canal therapy together with antibiotics that your dentist can prescribe.

If the infection and damage to the tooth are too severe and your dentist does not believe that a root canal will be successful, they may recommend removing the tooth to stop the infection spreading and affecting your health.

It’s important to appreciate that treatment for tooth decay will depend on the stage.  Your dentist will need to check your tooth and take some x-rays to give you the right diagnosis and treatment.

At the onset of a toothache, it’s worthwhile to visit your dentist early and get it checked out.  Quick action will not only save your tooth but save you money on extra treatments later.

Need a dentist in Port Macquarie?

Think you have a cavity and need a dentist in Port Macquarie NSW?  Contact the TL Dental team today on 02 6583 4055 . Emergency dental visits are typically seen and treated on the same day and we can also able to provide prescription only pain relief medication for severe pain.

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