5 Tooth Decay Stages

Tooth decay stages are the progression from having healthy teeth to bad teeth that may even need the removal of some tooth in extreme cases. The food we eat can stick to the teeth and become acidic if they are cleaned out. The food leftovers causes the mouth to become acidic and this can cause holes or cavities to form on the teeth. As these cavities are forming, tooth decays set in. It will take some stages for the decay to affect the inner layer of the teeth.

If there is no treatment, the teeth decay continues till the only treatment option is to have a root canal or remove the affected teeth. Before going into the stages of teeth decay, let us first explain what teeth decay is and the symptoms too.


Tooth decay is damage in the tooth which can lead to dental abscess, cavities and tooth removal in some cases. It is caused by bacterial activities that take place in the mouth leading to dental plaque. 

When you eat certain foods that contain sugar or starch, they stick to the surface of the tooth. If they are not washed off, bacteria in the mouth will feed on them and turn them to acid which will plaque building on the tooth. The plaque produced is acidic too and it wears out the enamel and creating holes in the tooth. 

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There are symptoms that can show you are having tooth decay, some of them are:

  • Black or brown spots on the tooth
  • Tooth sensitivity to hot or cold substances
  • Sudden mild or extreme tooth pain especially when eating or drinking
  • Holes or cavities in the tooth
  • Bad breath from the mouth
  • Bad taste in the mouth even after brushing
  • Abscess


There are five stages that tooth decay normally go through. These stages are:

1. First Stage – Demineralization

The first stage of tooth decay is the weakening of the outer layer of the tooth known as the enamel by the plaque. The enamel is the hardest substance in the tooth, it is even harder than some bones in the body. But this hard surface can be weakened and demineralized by acid produced in the mouth, this is to show how damaging the plaque can be. 

When Demineralization starts, one of the symptoms will be white spots on the tooth, this is the plaque wearing off the tooth enamel. This first stage can be easily reversed by using fluoride toothpaste or mouth wash often to avoid further damage.

2. Second Stage – Enamel Decay

If there is no measure or treatment to stop the enamel from being damaged, the acid will continue to wear off and break down the outer layer of the tooth. You will also notice the white spots turning to brown or even black color. This is slowly progressing to the next stage where the enamel damages to the point where cavities and holes begin to form on the surface of the tooth.

To prevent these holes from becoming larger or to stop the progression of the decay, you will have to see your dentist to fill them with tooth fillings. The decayed debris in the enamel will be removed and filled as well.

3. Third Stage – Dentin Decay

If the holes in the enamel are not taken care of, the next attack or damage will be on the dentin. The dentin is under the enamel and is very delicate and sensitive. Unlike the enamel, the dentin is very soft and this makes it susceptible to damage by acid. 

The decay will speed up at this stage and you will feel your tooth being overly sensitive when you eat cold and hot substances even sugary foods. Dentin decay can be fixed if it is noticed very early. Your dentist can fill the holes with dental fillings if the damage is mild. But if the damage is much, the treatment method will involve removing the decayed part of the dentin and placing a crown over the tooth.

4. Fourth Stage – Damaged Pulp

The pulp is the part of the tooth under the dentin, it houses the tooth nerves, blood vessels that provide the tooth with nutrients and sensations. As the decay progresses to the pulp, you will notice swelling of your tooth. You will also feel severe pain that may make it difficult to eat. 

As the damage continues, the result can be death of the affected pulp, this condition is known as pulp necrosis. Symptoms that will show that your tooth pulp is dead include bad taste and smell even after brushing, tooth changes from white to gray and then to black and swelling of the tooth. To prevent further damage, the dentist can remove the damaged pulp, fill in the holes and cavities before covering the tooth with crown. 

5. Fifth Stage – Abscess Formation

This is the last stage and very dangerous. If the pulp is not treated or handled very well, bacteria can enter into the decaying pulp and lead to infection. With time, a pocket of pus may start to form around the bottom of the tooth. This will lead to intense pain that will affect and spread to the other parts of the gums, mouth, jaw and even the face as well. 

To treat this condition, a root canal may be done but in cases where the procedure does not treat the tooth decay, the only option is to remove the affected tooth to prevent the bacteria and infection form spreading to the bones in the the jaw and head. 

Tooth Decay Stages
Tooth decay stage


Toddlers can have tooth decay, it is not just a condition that is meant for adults. But one major difference is that it is easier for an adult to notice the stages of tooth decay, a toddler cannot identify tooth decay. They are unable to specifically identify where the pain is coming form or other symptoms of tooth decay. This is why it is important to take note of any change in your baby’s teeth.

The stages of tooth decay in toddlers and babies are:

1. Stage One: White Spots

This is the first stage, acid and plaques will start to accumulate on the tooth leading to wearing off of the enamel – the hardest part of the tooth. It is easier to reverse this demineralization process before the damage continues.

2. Stage Two: Enamel Decay

The continuous wearing off of the enamel will make it difficult for the tooth to get back the minerals they need. A hole may form inside of the tooth and breaks down the enamel. You need to see a dentist if you notice any hole in your baby’s teeth to avoid further damage and breaking of the surface of the tooth.

3. Stage Three: Dentin Decay

The dentin is under the enamel and before the tooth pulp. It is very sensitive and soft. As the decay continues to affect the enamel, it can break into the dentin and also start to break it down. Your child will start to feel pain and sensitivity in the tooth especially when eating. To treat this pain and prevent the decay from becoming more severe, you will have to take your toddler to a dentist for dental fillings.

4. Stage Four: Pulp Deterioration

The pulp houses the blood vessels and nerves in the tooth. When the decay affects this part of the tooth, pus will accumulate around the pulp. This pus will kill the blood vessels and nerves leading to death of the pulp. Pain, swelling of the gum, bad smell will be some of the symptoms your toddler will have, you may also notice some of them especially the bad smell and swelling. To treat this, your child will need a root canal to remove the infected pulp.

5. Stage Five: Abscess Formation

As the decay gets to the root of the tooth, abscess will form. This is very painful and dangerous as the gums and tongue will swell. The abscess can also infect bones in the jaw and head at this stage. It is recommended that your child gets immediate medical attention like root canal or even oral surgery in extreme cases.

6. Stage Six: Loss Of Tooth

This is the last stage and can be avoided if the other stages of tooth decay were managed well. The only treatment option at this stage is to extract the damaged tooth. If tooth extraction is not done, the infection can spread to other tooth.


Animals like dogs have tooth decay and there are stages as well. One thing you should know is that if tooth decay or periodontal disease is not treated, the results can be pain, infection, tooth loss and damage to vital organs like the heart, kidneys and liver.

The stages of tooth decay in dogs are:

Stage 1 

This is the stage of gingivitis or inflammation that is caused by bacteria and tartar in the tooth. There may also be swelling and thin red line on the gums too.  

Stage 2

There will be inflammation of the gums, bad breath , visible tartar on the tooth ( Lone Tree Veterinary Medical Center, 2018 ). There will be also 25 percent loss of tooth bone. To prevent further decay, professional dental cleaning will be needed to remove plaque and tartar.

Stage 3

There will be at least 50 percent of tooth bone loss and this will be seen on oral radiographs. The gums will swell and start to bleed, there will also be irritation. Pus will start to accumulate around the gums causing bad breath and pain. To treat this stage, the infected tooth will be removed.

Stage 4

Bone loss is more than 50 percent and your dog will experience severe pain. If there is no treatment, the other tooth may be infected. The infection from the damaged tooth can spread to other parts of the body through the bloodstream and can damage the body’s organs.


Tooth decay has stages from mild to extreme, this can lead to tooth extraction if there is no treatment till the last stage. To prevent tooth decay, you can brush your tooth twice a day with fluoride toothpaste, rinsing after eating and using fluoride mouthwash at least once a day. See your dentist if you notice any change in your teeth, you should know that damage to the teeth can spread to other parts of the body resulting to damage to organs. 

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