How to Spot a Cavity in an X-Ray


Dentists strongly advise scheduling regular dental checkups with us. By using x-rays, we can assess the health of your teeth and spot any potential issues before they worsen. Obtain the Best information about رادیوگرافی دنداپزشکی.

On a radiograph, cavities appear as dark areas due to decayed portions being less dense than surrounding enamel and dentin.

Tooth Structure

X-rays reveal the structure of teeth and their bony attachment to the jaw. Teeth are composed of various materials, from complex, dense enamel to porous dentin; in radiographs, more mineralized tissues appear light-colored, while less mineralized tissues, such as tooth decay or gum tissue, appear darker.

So, while a cavity on your tooth might be challenging to detect with just the naked eye alone, a dentist can spot it quickly with an x-ray. This is because cavities are holes in the tooth structure that absorb less X-ray radiation and thus appear darker on X-ray images.

When bacteria attack a tooth, acid gradually erodes its hard, mineralized enamel to leave weak points that allow bacteria to penetrate deeper into its soft, more mineralized dentin layer and eventually penetrate it completely. Over time, as more bacteria enter this environment, dentin tubules degrade further, creating pitting on an X-ray image and leading to pitting on the appearance of your X-ray image.

As dentin is more resilient than enamel, cavities take longer to progress from the chewing surface into the nerve tissue below. Therefore, dentists must catch cavities early while they’re still present on chewing surfaces and are more accessible to remove.


Enamel is one of the most complex substances in your body and forms the outer surface of your teeth, protecting the dentin beneath. It has semi-translucence that ranges in color from light yellow to grayish white and acts as a key barrier against temperature or chemical fluctuations that could otherwise lead to tooth decay, sensitivity, or infection. Unfortunately, though, enamel doesn’t contain living cells that can repair themselves when damaged.

Tooth enamel contains approximately 96% mineral composition and is comprised of mostly hydroxyapatite crystals that form hard glass-like material. Hydroxyapatite has the formula Ca5(PO4)3X, where X can either be fluorine or phosphorus. Hydroxyapatite forms tight crystal structures packed together tightly enough that its material becomes rugged, durable, and reliable for protection from tooth decay.

At each stage of tooth development, ameloblasts secrete a partially mineralized organic matrix composed of proteins to support and guide hydroxyapatite crystal deposition in the enamel matrix. Ameloblasts also release proteases, which break down the organic matrix by extracting water and protein molecules, leaving room for new crystal formation.

Gnarled or striated enamel, visible when looking at your teeth from the side, is caused by the orientation of hydroxyapatite crystals in their matrix. When aligned correctly, these crystals make long prism-like structures resistant to fracture by forming long prisms. Enamel is a highly anisotropic material with mechanical properties differing by up to three times between the outer enamel surface and DEJ due to the differing orientation of its crystal rods within it.


Dentin forms most of a tooth’s structure beneath the enamel and houses nerve tissue and blood vessels in its pulp cavity. It is mainly comprised of hydroxyapatite, with some collagen or organic materials mixed in as well. Dentin structures are solid due to their tubules running along curved pathways—these primary curvatures help further reinforce them.

Dentin is less calcified than enamel, causing it to appear darker on an X-ray and giving an early clue for cavities in their early stages. A darker appearance on an X-ray reflects how much decay has formed—the darker an area appears, the further along it has progressed.

Regular dental visits and good at-home oral care habits can significantly lower your risk for cavities. X-rays can detect cavities when they’re still small and only in enamel, potentially saving money and pain in later stages. Fluoride treatments and sealants may provide sufficient treatment. More extensive damage will require more involved processes like root canal therapy or fillings. Different kinds of cavities appear differently on an X-ray, providing dentists with valuable information. Interproximal caries (cavities between teeth) typically present themselves as dark spots on the chewing surfaces of teeth, while occlusal caries (cavities located directly within teeth) often manifest themselves by appearing directly within those chewing surfaces of individual teeth themselves.


X-rays can detect cavities in the pit and fissure of your teeth, but only advanced cavities will show up on an X-ray. Furthermore, your dentist must take extra care not to expose you to unnecessary radiation, as pregnant women and others with certain illnesses should avoid excessive radiation exposure.

An X-ray shows a lot about the state of your teeth. Shallow cavities leave a lighter shadow as an early warning signal; deeper cavities create darker spots, which indicate severity. Furthermore, their location provides valuable clues: those nestled between teeth or along root surfaces require different treatment approaches than those located on biting surfaces.

Human peripheral nerves have been studied using radiography and computed tomography (CT), but to our knowledge, x-ray phase contrast holographic nanotomography has never been applied as an assessment technique to these structures in human subjects1. Utilizing this technique, we were able to produce 3D reconstructions of human posterior interosseous nerve biopsies from healthy individuals as well as diabetic patients. These reconstructions revealed that osmium-stained myelin sheaths and sizeable myelinated nerve fibers could be easily distinguished from their surrounding bone. Furthermore, 3D reconstructions of diabetic specimens revealed nerve fascicles with segments of degenerated axons as well as sprouts of regenerated ones.