11 Main Causes of Dental Caries (According to Experts)

Dental caries, commonly known as tooth decay or cavities, is a widespread oral disease affecting your general health. It may cause severe pain and infection in your mouth and is often very expensive to treat. If not treated early, it can lead to tooth extraction and tooth loss.

This article discusses the main causes of dental caries by consulting research articles, expert interviews, government agencies, and educational material.

We strongly believe you will have a complete idea of what dental caries is and how it may affect your health and life after reading this article.

Let’s get started.

11 Main Causes of Dental Caries

1. The uncontrolled presence of bacteria in your mouth

You need to have dangerous bacteria in your mouth to have dental caries.

It is important to recognize that we have naturally occurring bacteria in our mouths. They are there, feeding on the food residue and always attacking our teeth.

We keep them under control by brushing our teeth, flossing, and going for dental exams and treatments at dental clinics.

But when we do not clean our mouths, the bacterial population grows and rapidly goes out of control. The result is enamel erosion or tooth decay.

2. High sugar intake

Bacteria are living organisms, and they need carbon to survive. When you supply sugar to them, they break it down to obtain the carbon.

Sugar comes to your mouth from different sources. However, the following are the most common ones:

• fruit-based drinks
• milk-based drinks
• fruit juice
• confectionery
• sweetened cereals
• sweet desserts
• honey
• preserves

Interestingly enough, bacteria are known to prefer some sugars to others. For example, Escherichia coli bacteria consume d-glucose before turning to l-lactose. The truth remains that both d-glucose and l-lactose are consumed sooner or later.

3. Formation of plaque, a natural habitat for bacteria

The bacteria constantly create plaque in your mouth. Plaque is a sticky film of bacteria that hardens with time. The film is sometimes called a biofilm of microorganisms.

Not only your teeth, but the film may also stick to your dental restorations and prosthetics, including dentures and bridges.

The plaque needs only 24 hours to harden. If you do not brush your teeth for a single day, your oral health may be compromised. However, you may not notice the harm done with your naked eyes for about 3 months.

Good to know: According to Odontology, about 1000 species of bacteria exist in dental plaque.

4. Habits of extreme teeth grinding and clenching

Otherwise called bruxism, the grinding and clenching of teeth can cause tooth damage, headaches, and temporomandibular disorders, let alone dental caries.

Bruxism has the following characteristics:

• It is involuntary. You do not eat anything when you grind or clench your teeth
• It can happen when you are awake or asleep
• Stress or anxiety can trigger it
• Awake bruxism is more prevalent in females as compared to males.

Bruxism damages the tooth’s surface, thus encouraging bacteria to attack it and cause infection.

5. Inadequate salivary flow in the mouth or xerostomia

Xerostomia, or dry mouth, is an oral condition arising from the side effects of different medication or radiotherapy treatments for cancer. (Radiation therapy causes quantitative and qualitative changes in the saliva-producing glands). You may get dental caries if your mouth does not produce enough saliva.

Let me explain how it works.

• Xerostomia contributes to developing mucositis (sore mouth) and oropharyngeal colonization with Gram-negative bacteria.
• A reduced amount of saliva in the mouth makes the mouth more susceptible to dental caries by causing the following:
  • Periodontal disease (inflammation of the gums and bone)
  • Halitosis (bad-smelling breath)
  • Candidiasis (fungal infection)

If you have dry mouth syndrome, consider the following:

• Drink water frequently
• Chew sugar-free gum or candy
• Avoid hard-to-eat-or-chew foods
• Do not consume tobacco, alcohol, or caffeinated products
• Get treatment for any dehydration-related condition
• Maintain good oral hygiene

5. Your Gastroesophageal reflux disease (GERD), or chronic acid reflux, is causing it

According to The American Academy of Allergy, Asthma & Immunology (AAAAI), chronic acid reflux affects people of all ages.

Acid reflux is a condition in which gastric acid flows from your stomach to your mouth following the food pipe.

Acid reflux causes the tooth enamel to lose minerals. The enamel continues to weaken if not treated, leading to complete destruction. Since the enamel cannot be regrown, the damage is permanent and non-reversible.

Some of the possible causes of acid reflux include the following:

• Digestive disorder
• Overweight
• Overeating
• Consumption of caffeine and alcohol
• Eating spicy food
• Eating chocolates

If you have severe acid reflux disease, you may experience heartburn, sore throat, hoarse voice, and chronic cough. You may also have a bad taste in your mouth.

6. You have a silent disease called osteoporosis which is accelerating your dental caries

Osteoporosis can lead to severe gum infection and tooth loss.

It means a lifelong lack of calcium in your body, which may result in reduced bone density and loss.

But how is osteoporosis related to dental caries?

If your body lacks calcium, it will start taking calcium from your bones and teeth. The result is ever-weakened teeth, which easily fall victim to bacterial infection.

Your teeth need calcium and phosphate to develop their hard structure. In the absence of the required percentage of calcium, the integrity of the tooth structure is compromised, and you may experience the following:

• Weak teeth roots
• Teeth chip or break easily
• Tooth decay (dental caries)
• Gum infection
•  Cataracts
• Alterations in the brain

7. Inadequate exposure to fluoride is behind your dental caries

You need to have fluoride in water, toothpaste, or both. Drink community water instead of bottled water. Bottled water does not contain fluoride unless specifically mentioned. In addition, choose fluoride toothpaste to keep your teeth strong.

Teeth enamel rich with fluoride is more resistant to acidic attack or decalcification. They remineralize themselves when pH increases.

If the drinking water is not adequately fluoridated, children from 6 months through 16 years can use oral fluoride supplements.

Besides using fluoride toothpaste, you may consider the following to prevent caries:

• Get a prescription for high-fluoride toothpaste from your dentist
• Get a fluoride application on your teeth at the dental office
• Consider getting a silver diamine fluoride (SDF) application. SDF leaves a black stain on the damaged part of the tooth. However, it does not stain teeth with healthy enamel
• Use a custom-made fluoride carrier

8. You have not seen your dentist regularly

If you are not a dentist or hygienist, you may not know that you have dental caries. Tooth decay is a continuous process; you notice it only when it becomes severe.

That is why visiting your dentist in a timely manner is important. Your dentist may detect caries before they become severe and create a treatment plan for you.

Understand that a severe dental caries situation may lead to root canal treatment, tooth extraction, or dental implant, all of which are expensive treatments in their own way.

Besides, losing one tooth to caries does not say all about it. The missing tooth may cause bone loss in the jaw, misalignment of the teeth, jaw pain, and many other complications. They all may be prevented by visiting your dentist regularly.

9. You suffer from bulimia nervosa or eating disorders which is causing your tooth decay

Bulimia is characterized by overeating. It is called bingeing. It is a life-threatening disorder. But it is also related to your dental health.

According to the National Institute of Dental and Craniofacial Research (US), bulimia can cause the following:

• Dental erosion
• Dental caries
• Xerostomia or dry mouth
• Dehydration

All of these are related to tooth decay.

Medical science does not exactly know what causes bulimia. However, the following have been identified to work behind it:

• Genetics
• Metabolism
• Emotional issues
• Social issues
• Negative self-esteem

10. Substance use/abuse can cause dental caries

If you have been using illicit substances like methamphetamine, you may have dental caries.

Methamphetamine is Desoxyn, a stimulant medication usually prescribed to treat Attention deficit hyperactivity disorder (ADHD) symptoms. However, abuse of this stimulant can cause serious tooth decay. It may also cause the following:

• Dry mouth
• Enamel erosion
• Gum inflammation
• Tooth wear
• Bruxism
• Excessive food intake or bulimia
• Craving for high-sugar beverages
• Failure to pay attention to oral hygiene

The drug shrinks the salivary glands, thus decreasing the flow of saliva inside your mouth.

11. You are suffering from systemic sclerosis

Systemic sclerosis is a disorder that affects your skin and internal organs, including the following:

• Muscles
• Joints
• Blood vessels
• Lungs
• Kidneys
• Heart

But it also causes serious damage to your oral health, including the following:

• Dental caries
• Dry mouth
• Gum infection
• Gum recession
• Bone loss
• Small mouth or microstomia

Dangers and complications related to dental caries

Complications related to dental caries include, but are not limited to, the following:

• Tooth destruction
• Infections in the mouth
• Possible tooth extraction
• Missing teeth replacement surgeries
• Movement of the adjacent teeth
• Abnormal eruption of the permanent teeth.

And many more.

Dental caries, according to Harvard fellows

According to Harvard Catalyst, dental caries has the following three causes:

• Acids produced by bacteria lead to the loss of calcium
• Micro-organisms (bacteria) destroy the enamel protein
• Keratolytic micro-organisms produce complex compounds (plaque) that lead to decalcification

Yale Scientific on fluoride treatments

Yale Scientific argues that using fluoride tooth and flossing cannot end enamel loss in a person. The reasons for that are the following:

• Fluoride strengthens the tooth enamel, but it does not get rid of the existing dental caries
• Fluoride can be left ineffective by certain oral conditions, such as tooth structure, dry mouth, and bacterial interactions (bacteria’s genetics, sensing and signaling systems, etc.)

Dental Caries: Recommended Reading

We recommend the following book for further exploration of dental caries as a topic of discussion.

Essentials of Dental Caries, by Edwina Kidd and Ole Fejerskov. Oxford University Press. June 2016. Online edition, Oxford Academic, 12 Nov. 2020.

Online ISBN: 9780191916861

Print ISBN: 9780198738268

Here is a screenshot of the content of the book:

Also from SupreDent:

• 11 Main Reasons Your Teeth Feel Rough
• Acid Reflux Disease and Tooth Erosion
• 17 Leading Causes of Black Gums Around Teeth
• 14 Reasons You Have Metallic Taste in Your Mouth
• 10 Reasons The Roof Of Your Mouth Is Itchy
• 10 Reasons The Roof Of Your Mouth Hurts

References for dental caries:

Beisel CL, Afroz T. Rethinking the Hierarchy of Sugar Utilization in Bacteria. Journal of Bacteriology. 2015 Nov 16;198(3):374-6. 

ten Cate, J. Biofilms, a new approach to the microbiology of dental plaque. Odontology 94, 1–9 (2006).

Shetty S. et al.. Bruxism: a literature review. The Journal of Indian Prosthodontic Society. 2010 Sep;10(3):141-8. 

Dennesen P. et al. Inadequate salivary flow and poor oral mucosal status in intubated intensive care unit patients. Critical Care Medicine. 2003 Mar;31(3):781-6. 

Talha B, Swarnkar SA. Xerostomia. [Updated 2022 Oct 27]. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2022 Jan.

Bernard J. Hennessy. Caries. Merck Manual. Accessed on Dec 14, 2022.