Do cavities always show up on xrays?

This blog post will address the topic, “do cavities always show up on x-rays” and cover topics like what research says, 7 ways to tell if you have a cavity or not, signs and symptoms that indicate that you have a cavity, what is a cavity and how does it form and how can you prevent cavities.

Do cavities always show up on x-rays?

Yes, cavities do always show up on x-rays, once it has destroyed at least 40% of the enamel layer. However, the accuracy rate of detecting a cavity in its earliest stage is low.

Early detection of cavities depend on the location of the cavity as well as the accuracy and precision of the x-ray machine used.

Proximal cavities are hard to diagnose at the earliest and have an accuracy rate of less than 50% with panoramic x-ray technique as reported by a study.

What Does Research Say?

According to a research study, for cavities to show up on x-rays, the demineralisation of the enamel must be at least 40%. 

The same study reports that detection of proximal caries especially on the posterior teeth is extremely difficult and does not always show up on x-rays in its early stages.

A study reported sobel edge detection method for detecting early cavities with an accuracy of 96%. 

So we can see that no technique or tool guarantees 100% accuracy of detecting cavities or caries in their early stages.

7 Ways To Tell If You Have A Cavity Or Not

Clearly Visible Hole On Your Tooth

Cavity is a hole that can be seen or felt with the help of your tongue. Hole on your tooth or teeth is an indication that you might have a cavity formed.

Tooth Pain 

Pain in the tooth is an indication of cavity that has reached pulp. When cavity is ignored in its earliest stage, it deepens to enter dentin and finally enter pulp causing infection, resulting in pain.

If pain is felt in the tooth, it may be a cavity and you must consult your dentist.

Tooth Sensitivity

Tooth sensitivity is an indication of cavity reaching dentin. 

When the cavity in its earliest stage is not repaired or filled or healed naturally through good oral hygiene and calcium rich foods, it deepens and reaches dentin.

On reaching dentin, the dentinal tubules are exposed and sensitivity develops on eating or drinking something hot or cold or sugary.

Tooth Darkening

If you see your tooth getting darker in color, it may be due to tooth decay or cavity.

When cavity exposes pulp tissue, bacterial invasion occurs and pulp gets infected. 

Infection in the pulp is manifested as excruciating pain, sensitivity and darkening of the tooth.

At this stage, consult your dentist or an endodontist to get a root canal done.

If the tooth infection has destroyed the entire tooth, then extraction may be the only option.

Tooth Abscess And Pus 

Sometimes you may not notice a hole or you may not initially experience pain or sensitivity or you may experience an occasional pain and sensitivity that might be ignored by you.

In any of the above case, you miss out on noticing a cavity, resulting in cavity deepening and finally causing tooth abscess and pus accumulation around the infected tooth.

Bad Breath

Persistent bad breath may be an indication of poor oral hygiene and cavity formation. 

Cavity that deepens and results in tooth infection, causes halitosis which does not go away even after mouthwash or brushing.

If you have persistent bad breath, you must consult your dentist for an oral examination.

Tooth Fracture

If you notice your tooth fractured suddenly or after eating any hard food, then it must have developed a cavity. 

Cavity weakens your tooth and it might not withstand the biting force and fracture.

Signs & Symptoms That Tell You That You Have A Cavity

If you have a cavity, you might notice some of these signs and symptoms:

  • Holes in your teeth.
  • Sudden pain and sensitivity to drinking or eating something cold or hot.
  • Sensitivity on eating sweets or acidic drinks.
  • Pain on biting.
  • Fracturing of teeth upon normal biting.
  • Blackening or brown stains on teeth

What Is A Cavity And How Does It Form?

Dental Cavity or tooth cavity, is a hole that develops on the surface of the tooth due to loss of mineral content from the enamel, resulting from the repeated acid attack by the plaque bacteria.

When you see a hole in your teeth or darkening of the teeth, you must consult your dentist as it may be a cavity.

Consumption of sugary and starch rich foods expose the tooth to acids frequently, resulting in mineral loss from the enamel.

Infrequent tooth brushing habits cause poor oral hygiene, resulting in plaque accumulation.

Plaque is a sticky film containing bacteria that coats the protective enamel of your teeth. These bacteria produce acids by breaking down the food debris and the acids penetrate the enamel leading to formation of white spots on the teeth.

The cavity formation takes place in 5 stages:


  • Appearance of the white spots on the surface of the tooth as the mineral loss begins from enamel due to bacterial acid attack.
  • This stage can be reversed with preventive actions and maintaining good oral hygiene.


  • If the white spots are ignored and no preventive actions are initiated, the repeated acid attacks wear down the mineral and enamel is decayed
  • Visible hole is seen and now the cavity becomes irreversible.


  • The decay moves down further and attacks the inner soft dentin
  • This is called as Advanced Cavity Stage
  • Slight pain and sensitivity starts


  • In this stage, the decay finally reaches the pulp and irritates the nerves
  • Pain, sometimes excruciating, Sensitivity and Discomfort is seen in this stage.
  • Root Canal is the only treatment option other than extraction.


  • After pulp involvement, if treatment is not initiated, the infection spreads to the surrounding structures of the tooth and inflammation is caused
  • Extreme pain and even tooth loss may result

How Can I Prevent Cavities?

  • Daily brushing twice following correct technique.
  • Brushing with a mild abrasive toothpaste containing fluoride.
  • Daily flossing
  • Occasional use of therapeutic mouthwash.
  • Oil pulling has shown potential to prevent cavities.
  • Keeping yourself hydrated.
  • Frequent munching on snacks must be avoided and if done, must be followed by brushing teeth with just water.
  • Diet rich in vegetables and foods with sufficient calcium and vitamin D.


This blog post addressed the topic, “do cavities always show up on x-rays”. We understood what research says, 7 ways to tell if you have a cavity or not and signs and symptoms that indicate that you have a cavity. The article outlined what a cavity is, how it forms and how you can prevent cavities.

FREQUENTLY ASKED QUESTIONS (FAQs): Do Cavities Always Show Up On X-Rays

Can An X-Ray Miss A Cavity?

Yes, an x-ray can miss a cavity if it is in its early stages and have yet not caused 40% demineralisation of the enamel.

Sometimes, proximal cavities on the posterior teeth are also difficult to detect on x-rays during their early stages.

Can You Have A Cavity And Not See It?

Yes, sometimes you may have a cavity and not see it. The reasons may be that the cavity hole is very tiny or the cavity is still in its earliest stage and you miss the white spots on the tooth or maybe it is an proximal cavity on the posterior side.

What Does Beginning Of Cavity Look Like?

Beginning of the cavity appears as white spots on the surface of the tooth as the mineral loss begins from enamel due to bacterial acid attack.


Are All Holes In Teeth Cavities?

Yes, all holes in teeth are cavities and must be examined by a dentist for further treatment.

The holes in teeth are cavities and they develop due to demineralization of the enamel caused by bacterial attack and acid production.

How Long Does A Cavity Take To Destroy A Tooth? 

It can take a few months to years for a cavity to destroy a tooth depending upon the overall oral health and hygiene of the patient and their dietary habits.

Eating and drinking acidic foods and drinks can expedite the entire destruction process along with poor oral hygiene.


Naam, J. (2017). Accuracy of Panoramic Dental X-Ray Imaging in Detection of Proximal Caries with Multiple Morphological Gradient (mMG) Method. JOIV: International Journal on Informatics Visualization, 1(1), 5-11.

Şenel, B., et al. “Diagnostic accuracy of different imaging modalities in detection of proximal caries.” Dentomaxillofacial Radiology 39.8 (2010): 501-511.

Other FAQs about Teeth cavities that you may be interested in.

Do apples cause cavities?

Do cavities go away after filling?

Do cavities mean bad hygiene?

7 Proven Ways How to Tell If You Have a Cavity

Cavities – How to Tell if You Have One – WebMD

The Tooth Decay Process: How to Reverse It and Avoid a Cavity. (2018)

5 Amazingly Simple Things You Can Do to Prevent Cavities. (2017)

Cavities/tooth decay – Symptoms and causes – Mayo Clinic

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