Is tooth decay reversible?

is tooth decay reversible

Tooth decay is the most common dental problem and 1 in 4 individual in the US has untreated tooth decay. It is a diet-mediated disease and takes a long time for the bacteria to destroy different layers of the tooth. Several other factors also play a role in its development ans the process doesn’t happen overnight. In this article, I will walk you through the various stages of tooth decay, the stage where tooth decay becomes reversible and irreversible and the ways to reverse and treat them.

Let’s get started:

Is tooth decay reversible?

Yes, tooth decay is reversible and can be arrested and reversed in the early stages. Tooth decay initiates as a result of plaque accumulation on the teeth. A diet high in refined foods and bad oral hygiene promote plaque accumulation on the teeth. 

Dental plaque contains nasty bacteria that produce organic acids from the simple sugars in the diet. The organic acid erodes and softens the dental enamel and allows passage for the bacteria to enter the tooth. The enamel is a highly mineralized tissue that protects the deeper layers from the harsh oral environment. Dentin and pulp, on the other hand, contain organic matrix and less minerals and are, therefore, easily destroyed by the bacteria. 

After an acid attack, bicarbonate and phosphate ions from saliva neutralize the acid and returns the lost minerals to the teeth. However, it takes 20-30 to raise the pH back to normal. Frequent episodes of acid attack gradually demineralize the enamel until the entire thickness of the enamel loses its minerals, opening gates for the bacteria to enter the tooth. 

The most common sites for enamel demineralization are pits and fissures on the chewing surfaces and proximal surfaces of the back teeth. The smooth surfaces of the teeth are often spared and don’t decay. 

Enamel demineralization is the stage where tooth decay can be arrested and reversed. It appears as chalky white or hard black discoloration on the tooth. Also, the rate of enamel destruction is directly proportional to sugar in your diet and oral hygiene practices. 

What are Sugars – the leading cause of enamel decay

Sugars or simple carbohydrates are small chain molecules easily broken down by the oral (mouth) bacteria. The complex carbohydrates, on the other hand, are composed of complex and long chains of carbohydrates that aren’t utilized by bacteria and, hence, don’t cause tooth decay. 

Sugars are classified as monosaccharides and disaccharides.

Monosaccharides are 3-8 carbon atoms long molecules and are the building blocks for complex carbohydrates—for instance, glucose in white sugar, fructose in fruit juice, and lactose in milk.

Disaccharides consist of two monosaccharide units, but not polyols present in sugar-free sweeteners—for instance, glucose and fructose in fruit juice. 

Is tooth decay reversible

According to the Committee on Medical Aspects of Food and Nutrition Policy, sugars are categorized into two main types:

Intrinsic sugars 

Intrinsic or natural sugars are the sugars where the sugar molecules are trapped within food’s cell structure, such as fresh fruits. These sugar, if taken in moderate amounts, benefit teeth, gums and overall body because of their high vitamins, minerals, and fiber content. The fiber cleanses the teeth and wipes the sugar released during their breakdown. 

Extrinsic sugars 

Extrinsic sugars are the sugar where sugar molecules aren’t trapped inside the food’s cell structure, but are added to the food—for instance, white sugar added to cakes and breads.

Extrinsic sugars are further subdivided into:

Milk Sugar is a natural sugar known as lactose and is present in milk and milk products (e.g., cheese and plain yogurt). It is less likely to cause tooth decay than non-extrinsic sugar because of the presence of other essential nutrients such as fats, proteins, minerals, and vitamins. In fact, milk provides nourishment to the developing teeth and bones.

Non-milk extrinsic Sugar is a free sugar, which generally leads to tooth decay. It has no nutritional value and add unnecessary calories to the food. They include all the monosaccharides and disaccharides.

WHO recommendation for daily sugar consumption

WHO recommends an average consumption of 6 teaspoons of white sugar daily to a maximum of 12 teaspoons for the healthy teeth and gums.

How does sugar cause enamel demineralization?  

Foods with high glycemic index, such as cakes, biscuits, candies, and ice cream, are associated with tooth decay. The white sugar present in these foods plays a crucial role in dental decay. Sucrose is a chemical name for white sugar and is composed of glucose and fructose molecules.  

The consumption of processed and refined foods increases the rate of tooth decay and enamel demineralization because of the following factors: 

  • The low molecular weight sugars, such as glucose [in white sugar and processed and fast foods, sucrose (in white sugar), fructose (in fruit juices), and lactose (in milk)], are quickly metabolized by oral bacteria into organic acid. However, starch and fiber are composed of long and complex chain of molecules and thus are not broken down by oral bacteria.
  • The decay-causing bacteria produce organic acids as a metabolic by-product, which lower the pH to 5.0 or lower, favoring enamel demineralization. 
  • The decay-causing bacteria can store sugars, which serve as a reservoir to be used for energy production between meals when sugars are not available.
  • The frequent episodes of acid production shift the balance of resident oral bacteria towards the bacteria that grows in an acidic environment leading to exaggerated tooth decay if the pH remains repeatedly low. 
  • Sucrose present in white sugar is associated with more tooth decay because it provides glucose and fructose molecules for the formation of extracellular polysaccharides in the dental plaque. Extracellular polysaccharides are sticky in nature and promote bacterial adherence to tooth surfaces. They also increase plaque porosity, enabling sugars to diffuse from the outer layers to deeper areas of the plaque. 
  • Plaque formed in the presence of sucrose has low levels of calcium and fluoride, which are critical ions in the enamel remineralization process.

When does tooth decay become irreversible?

Once the bacteria enter the dentin (the second layer of the teeth), they destroy the tooth relatively faster as dentin is less mineralized and contains more organic material than enamel. 

The process of tooth decay becomes irreversible once it’s in the dentin. At this stage, you need to go for a filling to remove the decay and stop its progression. 

Dentin is thicker than enamel and forms the bulk of the tooth. The tooth decay progression is directly linked to your dietray habits and the type of predominent bacteria in the mouth. Based on these factors, it may take months or even years to reach the pulp and cause toothache. 

When the pulp gets involved, root canal therapy is done to remove the infection and save the tooth. 

How to reverse tooth decay?

Early tooth decay involving enamel demineralization can be reversed by following the treatments and home care:

Oral hygiene maintenance

Incorporating these habits into your daily routine help prevent dental cavities from developing and arresting them at an early stage:

  • Brushing twice daily with fluoridated toothpaste is the key to healthy teeth. Fluoride from toothpaste incorporates in the demineralized enamel and forms fluorapatite crystals, which are more resistant to acid attack. 
  • Brushing teeth for at least two minutes is essential to complete plaque removal. Ensure to clean all the tooth surfaces; outer, inner and chewing surfaces of the upper and lower teeth. 
  • Brushing technique: Place your toothbrush bristles at a 45-degree angle on the gums and swipe it towards the biting surfaces. Brush each tooth well and when finished, swipe the toothbrush down the tooth, away from the gum line.  
  • Flossing once daily prior to brushing disintegrates and removes the plaque present in between the teeth. 
  • You can use a water flosser if it is difficult to use a thread floss.
  • An electronic toothbrush is also helpful in effectively removing plaque from the teeth. Electric toothbrushes have pressure sensors that provide controlled cleaning stokes on your teeth that are neither too hard nor mild for the teeth. Some brushes have timers that can help you brush your teeth for two minutes.  
  • Use of Toothpaste with 1.5% arginine and 1450 ppm (parts per million) fluoride or sodium monofluorophosphate is also effective in arresting early tooth decay. 

Diet management

Diet management is the second most crucial aspect when managing tooth decay. Staying away from a western diet rich in refined, processed, and high glycemic index foods keeps tooth decay in check. 

Consumption of a diet high in simple sugars, such as sugar-sweetened beverages, processed and fast foods, increases overall calorie intake, but decrease the intake of nutritionally adequate calories, leading to weight gain, and increased risk of diseases, such as heart disease, diabetes, obesity, and tooth decay. 

Develop healthy dietary habits by introducing the following healthy options in your life.

  • Avoid any added sugars in food and drink.
  • Limit the amount and frequency of sugars-containing food and drinks consumed throughout the day.
  • Eat more fruits, vegetables, unprocessed wholegrain cereals, and grains. Always see the label for the sugar added to the cereal boxes and bars. 
  • Add high-protein foods such as lean red meat, poultry, fish, eggs, tofu, and legumes. Nuts and seeds also contain a bunch of good fats. 
  • Milk, yogurt, and cheese are rich in calcium, vitamin D, and good fats and are essential for teeth and overall health, especially in children.
  • Select healthy drinks such as milk and water instead of sugar-containing beverages.
  • Avoid sticky sugars with more sugar and less water content, such as dried fruits, fruit leathers, and hard or chewy sweets close to bedtime.

Fluoride treatment

It encourages remineralization of the enamel and arrests tooth decay decay at an early stage. 

Fluoride varnish: Fluoride varnish contains 0.1- 2.26% fluoride, a concentration higher than fluoridated toothpaste or mouthwash. It is applied on the clean teeth by the dentist and lasts up to 3-6 months

Fluoride gel and foam: Fluoride gel and foam both have a higher fluoride content. Acidulated phosphate fluoride gel (APF) with 1.23% fluoride ion creates a pH of approximately 3 in the local area and allow greater fluoride uptake by the enamel in an acidic environment. The gel or foam is poured into the tray, and you will be asked to bite over it. 

Also, fluoride foam causes lesser toxicity if ingested because the amount of foam required to cover the teeth is one-fifth the amount by weight needed for the gel. 

The fluoride foam is dispensed in a sponge-lined tray, and the patient is asked to bite on the tray for 4 minutes. The bubbles from the foam collapse on the tooth surface, releasing fluoride. The foam does not overflow the trays and helps prevent gagging.

Don’t eat or drink for 30 minutes after the treatment to ensure complete penetration of the foam into the teeth. 

Who can get Fluoride treatment?

American Dental Association recommends fluoride treatments for individuals who are at high risk of tooth decay. High-risk children below age six should recieve fluoride varnish applications at 3- to 6-month intervals. Fluoride gels and foams are not recommended at this age because of the risk of fluoride toxicity from swallowing. 

What are the high-risk patients for tooth decay?

Fluoride treatments are given to patients who are at a high risk of getting tooth decay. The patients are classified into different risk categories based on the cavities in the past three years and presence of one or more risk factors for tooth decay. 

The following are the risk factors for tooth decay: 

  • An increased number of tooth decay-causing bacteria
  • Poor oral hygiene
  • Enamel defects
  • Genetic abnormality of teeth
  • Many multi-surface teeth fillings
  • Chemotherapy or radiation therapy
  • Eating disorders (bulimia), drug or alcohol abuse
  • High sugar diet
  • An ongoing orthodontic treatment
  • Exposed root surfaces
  • Physical or mental disability with the inability of performing proper oral health care.

Low-risk patients 

No cavities in the mouth in the past three years and absence of risk factors leading to tooth decay. 

Moderate-risk patients

Children below 6 years:  No enamel decay or any cavity in the teeth in the past three years, but one risk factor leading to tooth decay is present. 

Older than 6 years: One or two enamel caries or cavities in the teeth in the past three years or the presence of one risk factor for tooth decay.

High-risk patients

Children less than six years: The following children are at a high risk of dental decay;

  • Any enamel decay or primary or secondary cavities during the last three years. 
  • Presence of multiple risk factors
  • Dryness of mouth due to medication, radiation, or health disorder
  • Suboptimal fluoride exposure 
  • Low-income family 

Individuals Older than 6 years: The presence of any of the following factors in the individuals above 6 years calls for fluoride treatment:

When to see a dentist?

If you see any changes in the teeth, such as a cavity, discoloration, pain, or sensitivity, consult your dentist and get it checked. Tooth decay is reversible if diagnosed at an early stage. 


Tooth decay is a diet-related disease and occurs due to poor dietary habits and bad oral hygiene. Tooth decay progresses slowly and may take months to years to reach the deeper layers of the tooth. 

Tooth decay is reversible in the early stages. Tooth decay in the enamel can be revered, however, involvement of deeper layers involves removal of tooth decay with a dental drill followed by a filling or root canal treatement.. 

Restoration of enamel demineralization involves oral hygiene maintenance, diet management, and fluoride treatments.

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