Black tartar forms when ordinary dental plaque hardens and picks up dark pigments from blood, bacteria, or substances like tobacco and tannin-rich drinks. While regular tartar is yellowish or off-white, the black variety signals that something extra is coloring the mineral deposits on your teeth, often a sign that tartar has built up beneath the gum line where it mixes with blood from inflamed tissue.
How Tartar Forms in the First Place
Every mouth contains bacteria that feed on sugars and starches left behind after eating. These bacteria form a sticky, colorless film called plaque that coats your teeth within hours of brushing. If plaque stays on your teeth long enough, minerals in your saliva cause it to harden into tartar (also called calculus). This hardening can begin in as little as 24 to 72 hours, and once tartar has formed, no amount of brushing or flossing will remove it.
Fresh tartar is typically pale yellow or white. It darkens over time as it absorbs pigments from food, drinks, tobacco, and the biological environment around it. The longer tartar sits on your teeth without professional removal, the darker and harder it becomes.
Why Tartar Turns Black
Blood From Inflamed Gums
The most common reason tartar turns black is its location. Tartar that forms below the gum line (called subgingival calculus) sits in direct contact with gum tissue that is often irritated and bleeding. Blood from damaged gums seeps into the tartar and breaks down, releasing iron-containing pigments that stain the deposits dark brown or black. This is why black tartar is strongly associated with gum disease. If your gums bleed when you brush or floss, subgingival tartar may already be forming out of sight.
Chromogenic Bacteria
Certain species of mouth bacteria produce dark pigments as a metabolic byproduct. One well-studied group includes Corynebacterium species, which are strongly linked to black dental staining. These bacteria create thin, dark lines or patches, particularly along the gum line. Black stains from chromogenic bacteria are especially common in children, affecting roughly 2% to 20% of kids depending on the population studied, with a pooled average around 9.4%.
Interestingly, children with these black stains tend to have fewer cavities. A meta-analysis of five studies found that children with black staining had about half the odds of developing cavities compared to children without it. Researchers believe the bacterial profile responsible for the dark color may actually outcompete the bacteria that cause tooth decay. That said, the staining itself is still a cosmetic concern and can indicate tartar buildup that needs professional attention.
External Staining Substances
Several external factors accelerate the darkening of tartar:
- Tobacco: Smoking and chewing tobacco deposit tar and nicotine into plaque and tartar, turning them dark brown or black over time.
- Tannin-rich drinks: Coffee, tea, and red wine contain tannins that bind to tartar and deepen its color.
- Iron in water or supplements: Research has found that drinking water with high iron content is statistically associated with black dental staining. Iron supplements can have a similar effect, particularly in children, though the evidence is stronger for iron in drinking water than in pill form.
- High salivary pH: People whose saliva is more alkaline tend to form tartar faster, because the mineral-rich environment speeds up calcification of plaque. Higher pH in both saliva and drinking water has been linked to increased rates of black staining.
Black Tartar vs. Tooth Decay
It is easy to confuse a dark spot of tartar with a cavity, since both can appear as black or dark brown areas on a tooth. There are a few differences you can watch for at home, though only a dentist can confirm what you’re seeing. Tartar tends to form along the gum line or between teeth and has a rough, crusty texture you can sometimes feel with your tongue. A cavity, by contrast, is a hole or soft spot in the tooth itself and may cause sensitivity to hot, cold, or sweet foods.
Black tartar that sits below the gum line is invisible to you entirely. You might notice symptoms like persistent bad breath, swollen or bleeding gums, or a bad taste in your mouth, but the tartar itself can only be detected with dental instruments or X-rays.
What Black Tartar Does to Your Gums
All tartar irritates gum tissue, but black subgingival tartar is particularly damaging because it sits in the pocket between the tooth and the gum. Bacteria trapped in and around this tartar trigger a chronic inflammatory response. In the early stage, this shows up as gingivitis: red, puffy gums that bleed easily. Left untreated, the inflammation progresses to periodontitis, where the bone and connective tissue supporting your teeth start to break down. Over time, teeth can loosen and eventually be lost.
The relationship between black tartar and gum damage is cyclical. Tartar irritates the gums, causing them to bleed. Blood stains the tartar darker. The rough, dark tartar harbors more bacteria, which causes more inflammation and more bleeding. Breaking this cycle requires professional removal.
How Black Tartar Is Removed
You cannot remove black tartar at home. Unlike plaque, tartar bonds to tooth enamel and root surfaces so firmly that brushing, flossing, and mouthwash have no effect on it. Attempting to scrape it off yourself risks damaging your enamel, cutting your gums, and pushing bacteria deeper into gum pockets.
A dental hygienist removes tartar using a process called scaling. This involves specialized metal instruments and often an ultrasonic scaler that vibrates at high frequency to break tartar free without harming the tooth surface. For tartar that has accumulated below the gum line, a deeper cleaning called scaling and root planing is needed. This procedure reaches into gum pockets to remove tartar from root surfaces and then smooths the roots so gums can reattach more easily. Depending on severity, this may be done in one visit or across multiple appointments, sometimes with local anesthesia to keep you comfortable.
In advanced cases where gum pockets are deep and bone loss has occurred, surgical options like pocket reduction surgery or laser therapy may be recommended to access and clean areas that instruments alone can’t reach.
Preventing Black Tartar From Returning
Prevention comes down to removing plaque before it has a chance to harden. Brushing twice a day with a fluoride toothpaste and flossing daily are the foundation. An electric toothbrush can be more effective than a manual one at disrupting plaque along the gum line. Tartar-control toothpastes contain ingredients that slow the rate at which plaque mineralizes, which can help if you’re prone to heavy buildup.
Regular dental cleanings, typically every six months, catch tartar before it accumulates enough to darken or cause gum damage. If you have a history of gum disease or heavy tartar formation, your dentist may recommend cleanings every three to four months instead. Reducing tobacco use and limiting coffee, tea, and red wine can slow the external staining that turns tartar dark. If your drinking water has high iron content, a water filter designed to reduce iron may also help over time.
People with naturally alkaline saliva or those who form tartar quickly despite good hygiene are not doing anything wrong. Some mouths simply mineralize plaque faster. For these individuals, more frequent professional cleanings are the most effective strategy for staying ahead of buildup.