What are these Black Lines on Teeth and How to Remove them

Clinical image of black lines on teeth and the involved bacteria
Have you ever noticed black stains appearing as lines or dots on your teeth?

While they might resemble common dental issues like cavities, plaque, or tartar buildup, these stains are actually quite different. They belong to a specific form of tartar that is not harmful and does not indicate poor hygiene.

These black line stains are most commonly found in children, with a prevalence ranging from 2% to 20%, depending on the country studied. Though less common, they can also affect young adults.

But where do these unsightly black lines come from? What causes them, and how do they impact your oral health? More importantly, how can you effectively remove them?

In this article, we'll delve into all these questions and provide detailed insights on how to deal with black line stains for good.

What are these black line stains?

Black line stains, or simply "Black Stains," are a type of tooth discoloration that affects only the outer layer of your teeth, called enamel. They usually appear on baby teeth and disappear with age.

You might notice them as blackish dots, lines, or stripes that follow the contour of your gum line. Their exact cause is still unclear, but many agree on the involvement of certain chromogenic (pigment-producing) bacteria.

These black lines or stains are extremely sticky and can't be brushed off at home. So, no matter how diligent your oral hygiene, they tend to stick around.

black lines on primary teeth

What's interesting is that these black line stains aren't harmful to your teeth. In fact, studies have shown that people affected have a lower risk of cavities.

We can classify them into different categories based on their appearance and severity. Here's a breakdown according to Gasparetto et al:
The classification of black line stains on teeth according to Gasparetto et al.
  1. Discontinuous dots or lines that run parallel to the gum line.
  2. More visible continuous black lines that are limited to one-third of the tooth's height.
  3. Black lines and spots that are more extensive and go beyond the one-third mark of the tooth.

What causes black line stains to appear?

While we don't have all the exact answers, it seems that certain chromogenic bacteria are the culprits behind these stains. These bacteria interact with the iron present in the saliva.

The bacteria involved are called Actinomyces. They are some of the first to set up camp in a baby's mouth, within the first 5 months of life.

These bacteria produce something called Hydrogen Sulfide. When it interacts with the iron in saliva, it produces black compounds called Ferric Sulfide.

Over time, these black compounds get mixed up with plaque and other minerals found in the mouth, like calcium and phosphorus. And the result? Black deposits that firmly attach to the surface of your teeth.

Who is most at risk?

Certain factors seem to increase the risk of these spots forming. The most likely include:

  1. Age: Children are the most affected group by these stains. The good news is that they tend to disappear with age. This is partly due to hormonal changes, changes in saliva composition, and a reduction in the number of bacteria involved.

  2. Oral hygiene: Maintaining good oral hygiene is crucial for controlling the appearance of these stains. However, the methods and tools you use also play a role. Using more abrasive toothpastes can be beneficial in managing them.

  3. Diet: Food and drink play a crucial role in determining an individual's predisposition. Diets that are rich in iron and pigments, such as those found in tea, coffee, and chocolate, can increase the likelihood of these black stains appearing on the teeth.

  4. Medication: Taking iron-containing drugs or supplements can also contribute to this type of stain.

Do black line stains mean a higher risk of cavities?

We're all familiar with the negative impact of regular plaque and tartar on our oral health. However, black line stains are different in composition and formation. Individuals with these stains typically have a lower risk of cavities, and here's the reason why:

The plaque and tartar we commonly see in individuals with poor oral hygiene are primarily composed of cariogenic bacteria (the ones that cause cavities), such as Streptococcus and Lactobacillus, along with the products of their metabolism. These bacteria produce acids that eat away at the teeth' minerals, leading to cavities.

In contrast, black line stains contain a low number of cariogenic bacteria, which means fewer harmful cavity-causing agents are present.

Furthermore, the saliva of those with black lines tends to be richer in calcium. Calcium is beneficial for teeth as it strengthens and remineralizes enamel. With an abundance of calcium in the mouth and a limited number of harmful bacteria, people with black line stains are less susceptible to cavities.

The dark color comes from Iron, Copper, and Sulfur complexes. Therefore, apart from their cosmetic appearance, these elements do not pose a concern to oral health.

How to remove these black line stains for good?

When it comes to these black lines, the main concern is usually cosmetic rather than tooth decay or gum disease. However, the trickiest part is their tendency to reappear after treatment. So, before starting any removal process, it's essential to identify the cause and take preventive measures early on.

Since these stains are highly sticky and can't be removed at home, your dentist or hygienist can use different techniques to tackle them:

  1. Scaling: This method involves carefully removing the black deposits from the tooth surface using specialized tools.
  2. Air abrasion: Air abrasion employs a gentle spray of particles to precisely and efficiently remove the stains without damaging the tooth structure.
  3. Polishing: This helps to smooth the tooth surface and make it less susceptible to future stain formation.

While these stains can be effectively removed during a dental office visit, they often come back quickly if the root causes are not appropriately managed at home.

Moreover, frequent professional removal procedures can lead to enamel damage and wear. The best approach, therefore, is prevention. Here are some helpful tips:

  • Switch to an electric toothbrush: Electric toothbrushes can clean better and more effectively than manual ones, ensuring thorough removal of plaque and preventing stain buildup.

  • Use toothpaste with whitening and tartar control ingredients: Look for toothpaste containing active ingredients like mild abrasives and sodium hexametaphosphate, which helps prevent tartar formation.

  • Maintain good oral hygiene: Brush your teeth at least twice daily for two minutes each time, and don't forget to floss to remove plaque and debris from between your teeth.

  • Adjust your diet: Limit the consumption of foods and drinks high in pigments, such as tea, coffee, and colored sodas, which can contribute to stain formation. Rinse your mouth with water after consuming them to reduce their impact.

  • Avoid chlorhexidine-containing mouthwashes: If overused, chlorhexidine mouthwashes can cause staining and an increase in tartar buildup on your teeth.

  • Chew sugar-free chewing gum between meals: Chewing gum stimulates saliva production, which helps wash away bacteria and food particles, reducing the chances of stain formation.

Other dental conditions to rule out:

Before jumping to conclusions and self-diagnosing with the black lines we've discussed, it's crucial to rule out other dental conditions that might have a similar appearance. The most common are:

  • Cavities: These are caused by acid-producing bacteria that eat away at the tooth minerals, causing holes to form. On the other hand, black lines are a form of buildup that doesn't cause any pain or sensitivity.

  • Stains due to pigmented foods: Stains caused by consuming pigmented foods, such as tea, coffee, red wine, or certain fruits, can look similar to black lines. However, these stains typically cover a larger area on the tooth surface rather than being confined near the gum line.

  • Other forms of tartar buildup: Black lines can be mistaken for other forms of tartar or dental calculus. Tartar typically starts as a yellowish color and may darken when exposed to pigmented foods. In contrast, black lines appear dark right from the beginning. Another key difference is that black lines firmly adhere near the gum line area and have a limited height on the tooth surface.