Compulsive Nail-Biting and Oral Health

If you bite your nails frequently, you should know that there are consequences for your body. Here, we'll tell you how compulsive nail-biting affects your health.
Compulsive Nail-Biting and Oral Health

Last update: 21 August, 2021

Compulsive nail-biting, or onychophagia, does more than just cause aesthetic problems in your hands. It also leads to consequences for your oral health.

The habit of putting the fingers in the mouth is usually an unconscious action. Many times, it’s an indicator of an emotional conflict or is an imitated behavior. This problem can affect people of any age, being more common in childhood and adolescence. However, in some people, it continues into adulthood.

This habit, although it may seem harmless, can damage the mouth.

Keeping reading to find out how.

What is onychophagia?

Onychophagia is the name given to the habit of nail-biting. It’s a compulsive and unconscious behavior in which the person puts their hands in their mouth and nibbles the area at the end of the fingers.

Although the term refers to the nails specifically, it also refers to nibbling on the surrounding soft tissues, i.e., the skin surrounding the nails.

Another way to refer to the disorder is by the name of trichotillomania. In reality, this word refers to a somewhat more severe disorder, which includes pulling out the nails and even swallowing them. It has to do with psychiatric conditions such as obsessive-compulsive disorder, depression, or body dysmorphic disorder.

The origin of onychophagia has been related to stress. When a person faces repetitive situations of anxiety that they can’t resolve adequately, the gesture and the action serve as stress relievers.

There’s also a hypothesis regarding the patient’s persistence in the oral stages of psychological development. This would explain the tendency to put things in the mouth, including their fingernails.

A child biting his nails.
Onychophagia is common in children and adolescents. However, the habit can persist into adulthood.

General health problems caused by onychophagia

Onychophagia has specific consequences for oral health that we’ll analyze later.

But first, we’ll take a look at what happens in other body systems when there’s this compulsive practice. This is beyond the associated psychiatric conditions that may be present, which have their own signs and symptoms.

At the digestive level, the ingestion of the pieces of nails that come off when biting can alter how the stomach processes food. It’s possible that the production of gastric acid increases and that there’s dyspepsia, or, in other words, unspecific discomfort at the level of the upper abdominal area.

If we continue descending in the digestive tract, we’ll see the consequences in the small intestine. There, the pieces of nails may facilitate the entrance of parasites that will settle and produce symptoms according to each species.

Onychomycosis is another consequence. This is a fungal infection of the nails. As they’re injured and in constant contact with the mouth, increasing their surrounding humidity, fungi will have a favorable environment to settle.

It’s worth mentioning that nail mycosis is difficult to treat and requires long-term treatment with lacquers and the persistent use of medications. That’s why it’s a disease that should be detected early.

Just as onychomycosis is the fungal infection of the nails, when the soft tissues surrounding the hard part of the fingers are infected, it’s called paronychia, or panniculitis. The very act of repeatedly biting the area helps the microorganisms to enter the subcutaneous cellular tissue.

The consequences of compulsive nail biting on oral health

While the digestive system, the nails themselves, and the skin of the fingers are the most affected areas, compulsive nail-biting also leads to undeniable consequences for oral health. Both the teeth and the rest of the structures of the oral cavity are susceptible.

Let’s remember that the hands are always in contact with foreign substances and pathogens. We use these extremities to interact with the world around us daily.

With our hands, we touch viruses, bacteria, parasites, and dirt that we then take into our mouths when we bite our nails. But this isn’t all. There’s also mechanical stress on the surfaces of the dental elements that can wear down the enamel and even inflame the gums.

Let’s take a closer look at some of the consequences of onychophagia on oral health, which can be prevented by reducing the habit.

1. Compulsive nail biting prematurely wears down teeth

One of the consequences of onychophagia on oral health is the wear of tooth enamel. This happens due to the friction of the nails against the teeth and the rubbing of the teeth against each other.

As a result, the nail is cut and broken when biting; then, the teeth of the upper arch follow their mechanical stress with those of the lower arch. This leads to repeated microtrauma.

The microtrauma will be microfractures and, in extreme cases, will culminate in actual breaks in the surface of the teeth. While there may not be a breakage as such, there will be continuous and premature wear.

The upper central incisors are the most affected, due to their position and exposure to the habit. This is more evident in people who suffer from onychophagia due to stress and anxiety, as they usually also have bruxism (clenching and grinding of teeth).

2. Compulsive nail biting increases your risk of cavities

Cavities are a prevalent disease of the mouth. Their presence is explained by poor hygiene and oral care that results in bacterial colonization, responsible for the fermentation of carbohydrates in the diet.

This metabolism produces acids that demineralize the tooth. So, what would be the consequence of onychophagia in this case? It turns out that the bacteria present on the fingers and nails increase the colonization of the oral cavity.

The more bacteria there are, the greater the fermentation and the more acids can demineralize the hard tissues of the tooth. Consequently, the risk of cavities increases.

3. Halitosis

Halitosis is the technical name for bad breath. Its causes are varied, but the most frequent are related to poor oral hygiene and bacterial colonization. Therefore, as with tooth decay, one of the consequences of onychophagia for oral health is a bad odor inside the mouth.

As we said earlier, this compulsive practice can be part of major psychiatric disorders, in which general hygiene is affected. A depressed person, for example, will tend not to take care of their appearance and may not brush as often as they should.

Bacteria carried from the teeth to the mouth by onychophagia contribute to the substrate of halitosis. The hands are in contact with multiple external agents that favor the entry of microorganisms.

4. Compulsive nail biting can lead to infections in the mouth

The mouth has a flora of healthy microorganisms. Thus, some bacteria normally inhabit the oral cavity and don’t cause disease.

Assiduous contact with hands and unknown pathogens alters this balance. We’ve already mentioned that cavities appear as a consequence of this entry of bacteria, but other infections are possible; also due to viruses and fungi. Herpes labialis, for example, can be contracted by direct contact with the virus.

The halitosis we’ve already talked about isn’t always an isolated sign. Sometimes, it’s the expression of an ongoing infection caused by bacterial overgrowth. It’s worth mentioning periodontal disease here as a serious consequence of onychophagia in oral health.

At the same time, some mouth sores or aphthous ulcers are related to the colonization by microorganisms. These are very painful and self-limited ulcerations that resolve in about a week.

5. Temporomandibular disorders

The temporomandibular joint can suffer the effects of onychophagia, as the constant mechanical stress of chewing is capable of altering its function. This will bring pain when chewing food and abnormal jaw movements.

If we add bruxism due to generalized stress, then the risk of joint dysfunction rises. Some patients begin with ear pain as a manifestation of the disorder, due to the proximity of the structures to one another.

There’s evidence that bad habits cause temporomandibular disorders, so it’s not strange to associate onychophagia with this consequence for oral health. The problem is that it’s not only difficult to remove the repetitive action of nail-biting; it’s also difficult to correct a dysfunction of this joint.

A man holding his jaw in pain.
Dysfunctions of the jaw joint produce pain that’s easy to confuse with otalgia, due to the location.

How to avoid the consequences of onychophagia on oral health?

If we want to avoid the consequences of compulsive nail-biting on oral health, we have to take some measures to reduce the bad habit. These can range from psychological treatment to home and natural remedies to produce the rejection of the desire to bite.

When there’s a notorious alteration that affects the quality of life or that produces physical disorders such as those we mentioned, then it’s a good idea to seek psychological treatment with a professional. The psychologist will use various techniques, according to their training, for the approach.

A state of anxiety, depression, or stress that may be underlying the onychophagia will also be treated. Although each case is particular and the methods will be individualized according to the situation.

At the same time, the patient themselves can carry out home techniques to reduce their desire to bite their nails. Meditation, yoga, deep breathing, or any methodology that aims to control stress is welcome.

On the market, you can obtain and purchase nail polishes that give an unpleasant taste to the nail. This is done to discourage the habit of biting them. There are also false nails with the same function.

As for dentistry, the first recommendation is to make a consultation. The oral health professional will be able to corroborate if there’s already damage present and address it, as well as recommend ways to hinder the habit. If deemed necessary, they’ll refer the case to a psychologist.

Compulsive nail biting has health consequences

Onychophagia seems to be a minor problem when its consequences aren’t fully understood. However, the ultimate effect it has on the teeth, the digestive system, and the skin shouldn’t be underestimated.

If you or a loved one bites their nail regularly, we recommend that you start with a consultation. It can be with a dentist, a psychologist, or a physician. There may be a background of stress or anxiety that can be solved with proper treatment.

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