What Does a Cavity Look Like? Stages, Colors, and Warning Signs

By Lovik Mirzaeian, DDS. Updated September 2026.

What a cavity looks like depends on its stage. It usually starts as a chalky white spot on the enamel, darkens to a brown or black patch, and eventually becomes a visible hole or pit. Early cavities can look like faint stains, while advanced decay may show up as a dark opening, a broken edge, or swelling near the gums.

Knowing what a cavity looks like at each stage helps you catch decay while it is still small, cheap, and sometimes even reversible. This guide walks through the visual signs stage by stage, shows you how to tell a cavity from a harmless stain, and explains what your dentist sees on an x-ray that you cannot see in the mirror.

What Does a Cavity Look Like at Each Stage?

Tooth decay is a slow process, and its appearance changes as it moves deeper into the tooth. According to the CDC, cavities are one of the most common chronic diseases in both children and adults, so learning these stages is worth a few minutes of your time.

Stage 1: Chalky White Spots

The earliest visible sign of a cavity is a small, dull white patch on the enamel, often near the gumline or between teeth. It looks matte and chalky, not shiny like the healthy enamel around it. This happens because acid from plaque bacteria has pulled minerals out of the surface, a process fueled by how often sugar feeds the bacteria on your teeth. At this stage there is no hole yet, and with fluoride and better brushing the spot can often remineralize and never become a true cavity.

Stage 2: Brown or Black Spots

If the mineral loss continues, the white spot starts to break down and pick up color. You may see a light brown, tan, or gray spot that slowly darkens toward black. These spots commonly appear in the grooves of molars, along the gumline, or at the edge of an old filling. The surface may still feel smooth at first, but the discoloration sits in the tooth rather than on it, which is why brushing never removes it.

Stage 3: A Visible Hole or Pit

Once decay eats through the enamel into the softer dentin underneath, the tooth surface collapses and you can see an actual hole. It may look like a small dark pit, a shadowed area under the enamel, or a chip that keeps getting bigger. Food often packs into the opening, and floss may shred or catch at the same spot every time. Dentin decays faster than enamel, so a hole that looks small on the outside can be much larger inside.

Stage 4: Deep Decay Reaching the Nerve

When the cavity reaches the pulp at the center of the tooth, the visible damage is usually obvious: a large dark cavity, a broken or crumbling tooth, or a tooth that has turned gray or brownish overall. The gum next to the tooth may look red and puffy. At this depth a simple filling is usually no longer enough, and the tooth often needs a root canal or crown.

Stage 5: Abscess

An untreated deep cavity can lead to an abscess, which is an infection at the root of the tooth. Visually, you might notice a swollen bump on the gum that looks like a pimple, sometimes with a white or yellow head, along with facial swelling on that side. An abscess is a dental emergency even if it drains and temporarily stops hurting, because the infection is still there and can spread.

Cavity vs. Stain: How to Tell the Difference

This is the question behind most bathroom-mirror inspections: is that dark spot decay, or just coffee? The two can look similar, but they behave differently. Here is a side-by-side comparison.

Feature	Cavity	Stain
Color	Chalky white, brown, or black, often darkening over time	Yellow, brown, or gray, fairly uniform in tone
Location	One specific spot: a groove, the gumline, between two teeth, or beside a filling	Spread across the surface of one or many teeth
Texture	May feel soft, sticky, or rough; can become an actual hole	Smooth; the tooth surface stays intact
Edges	Irregular, often with a shadowed or translucent border	Blends gradually into the surrounding tooth
Response to cleaning	Does not change with brushing or a professional cleaning	Lightens or disappears with a professional cleaning or whitening
Change over time	Grows larger and darker; may start to catch floss or trap food	Stays stable, or slowly builds evenly with coffee, tea, or tobacco use

A useful rule of thumb: stains live on many teeth at once, while cavities pick a spot and dig in. If one dark dot keeps growing while the rest of your smile looks the same, treat it as a cavity until a dentist tells you otherwise.

What Do Cavities Look Like on X-Rays?

Some cavities never show up in the mirror at all. Decay between teeth or under an old filling hides where your eyes and even your dentist’s eyes cannot reach, which is exactly why x-rays are part of routine dental exams.

On a dental x-ray, healthy enamel appears bright white because it is dense and blocks the radiation. A cavity shows up as a dark spot or shadow where the tooth structure has been dissolved. Dentists look for a few classic patterns:

• A dark triangle or notch on the side of a tooth just below where it touches its neighbor, the most common spot for hidden decay
• A dark shadow spreading under the enamel into the dentin, wider inside than it looks on the surface
• A dark area beneath or beside an existing filling or crown, which signals recurrent decay
• A dark circle at the tip of the root, which can indicate an abscess

Small early lesions on x-rays are often just watched, since they may not have broken through the enamel yet. Larger shadows that clearly reach the dentin usually mean it is time for a filling. This is one of the biggest arguments for regular checkups: an x-ray can catch a cavity a year or more before you could ever see it yourself.

Early Signs You Can Spot at Home

You do not need special equipment to do a quick monthly self-check. Stand in good light, dry your teeth with a tissue (early white spots show up better on dry enamel), and look for these visual clues:

• Chalky, matte white patches near the gumline that were not there before
• A brown or black dot in the groove of a molar that does not brush away
• A gray or darker shadow showing through the enamel of a front tooth
• Floss that frays, shreds, or catches at the same spot between two teeth
• A dark line or gap forming at the edge of a filling or crown
• A tooth edge that looks chipped or thinner than its neighbor

Remember that looks are only half the story. Sensitivity to sweets, hot and cold, or pressure can develop alongside these visual changes. We cover those warning signs in detail in our guide to the symptoms of cavities, so if your tooth is telling you something even though it looks normal, start there.

When a Spot Needs a Dentist Visit

Not every mark on a tooth is decay, but some visual changes should never wait. See a dentist promptly if you notice:

• Any hole, pit, or catch you can feel with your tongue or see in the mirror
• A dark spot that has grown or darkened since you first noticed it
• Discoloration around an old filling or crown
• A whole tooth turning gray or dark compared to its neighbors
• A bump, pimple, or swelling on the gum near a suspicious tooth

If you only see a faint white spot and nothing else, you have a window of opportunity. Mention it at your next checkup, because early decay caught at the white-spot stage can often be reversed with fluoride and improved home care, with no drilling involved. The stages beyond that point only move in one direction, and the earlier a cavity is treated, the smaller and simpler the fix.

Frequently Asked Questions

Can a cavity look like a black dot?

Yes. A small black or dark brown dot, especially in the grooves of a molar, is one of the most common appearances of a cavity. Not every dark dot is decay, since stain can settle into grooves too, but a dot that grows, feels sticky to a dental instrument, or catches food should be checked by a dentist.

What does the beginning of a cavity look like?

The very beginning of a cavity looks like a dull, chalky white spot on the enamel, often near the gumline. The area loses its natural shine before any hole forms. At this stage the decay process can often be stopped or reversed with fluoride, careful brushing, and cutting back on frequent sugary snacks and drinks.

Can you see a cavity between your teeth?

Usually not. Cavities between teeth form at the contact point where neighboring teeth touch, hidden from view. Sometimes a gray shadow shows through the enamel once decay is advanced, and floss may shred at that spot. Most cavities between teeth are found on x-rays during dental checkups, often before any visible sign appears.

Do cavities always look dark?

No. The earliest cavities are white and chalky, and decay hidden under intact enamel can leave the surface looking nearly normal. Some advanced cavities appear as a gray shadow rather than a black hole. That is why a tooth that looks fine but feels sensitive or catches floss still deserves a professional look.

Spotted Something on a Tooth? Dr. Mirzaeian Can Help

If a spot in the mirror has you second-guessing, the fastest way to get an answer is a quick exam, so contact us to set up a consultation. Most spots turn out to be simple fixes, and catching a real cavity early keeps the treatment small.

Lovik Mirzaeian, DDS has achieved extensive training in multidisciplinary dental treatments. His credentials include Dental Implants, Cosmetic Dentistry, Full Mouth Reconstruction, Endodontics, Oral Surgery, Orthodontics, and Sleep Sedation. Our office puts your comfort and smile first, and we are dedicated to giving you top-notch dental care. Get ready to show off your perfect smile!

Looking for a trusted family dentist in Clovis? Dr. Mirzaeian welcomes new patients of all ages.