Ujangsan Dental Clinic: Why Does Dry Mouth Cause Cavities?

Hello.

I am dentist Kim Geun-il.

As you get older, when you are stressed,

or because of medication you regularly take,

have you ever felt that your mouth

becomes particularly dry?

It is easy to dismiss this as mild thirst

that can be resolved by simply taking a sip of water,

but from a dentist’s perspective,

the symptom of a dry mouth—xerostomia—is

one of the oral conditions that can undermine

the health of your teeth and gums.

I would like to explain what happens inside your mouth

the moment its moisture disappears.

Ujangsan Dental Clinic: Why Does Dry Mouth Cause Cavities?

Saliva, the “natural disinfectant”

in your mouth, disappears.

Saliva is not simply water;

it is a defense system that protects your mouth.

1. It washes away and disinfects bacteria

Saliva contains antibacterial substances

that kill bacteria.

It also flows continuously, helping wash away

food particles and bacteria attached to

your teeth and gums through a natural cleansing process.

2. It helps prevent tooth decay

When you eat, your mouth becomes acidic,

creating an environment where tooth decay can easily occur.

Saliva neutralizes this acidity and protects your teeth.

However, when saliva dries up due to xerostomia,

this strong protective barrier disappears,

and your mouth turns into an environment where bacteria can thrive.

It becomes an “acidic environment”

that is favorable for cavity-causing bacteria.

When saliva dries up, its ability to rinse the mouth stops,

allowing sugar and bacteria to remain in the mouth for longer.

Cavity-causing bacteria multiply much more actively in an acidic environment.

Because saliva can no longer neutralize the acidity,

teeth decay much faster than usual.

Gum-disease bacteria that dislike oxygen

become more active.

In addition to cavities, many of the harmful bacteria

that cause gum disease—periodontitis—

are bacteria that “dislike oxygen

and prefer sticky environments.”

1. Plaque and tartar build up quickly

When saliva dries up, it becomes more viscous,

so food particles and bacteria easily stick together,

causing plaque and tartar to form much faster.

2. Gums swell and bleed

As gum-disease bacteria

multiply rapidly, they attack the gums.

Eventually, your gums may bleed every time you brush,

become swollen, and, in severe cases, the bone supporting your teeth may deteriorate,

leading to loose teeth.

What is making my mouth so dry?

Xerostomia is not simply a natural phenomenon

that occurs with age;

it can also worsen for various reasons in everyday life.

1. Medication side effects

Many medications commonly taken by middle-aged and older adults,

including blood pressure medication, diuretics,

antidepressants, and allergy medication such as antihistamines,

can have the side effect of reducing saliva production.

2. The habit of breathing through your mouth (mouth breathing)

If your nose is blocked due to rhinitis or chronic sinusitis

and you constantly breathe through your mouth,

the passing air quickly evaporates moisture in your mouth.

3. Stress and inadequate hydration

When you are extremely nervous or stressed,

salivary gland activity may decrease,

which can reduce saliva production.

Four ways to protect

your mouth from xerostomia

1. Drink small amounts frequently

Rather than drinking a large amount all at once,

keep water nearby and drink it often

so that your mouth does not have a chance to become dry.

2. Use sugar-free gum or candy

This can help stimulate the salivary glands

and encourage natural saliva production.

(However, please choose products without sugar!)

3. Cut back on coffee, alcohol, and smoking

The caffeine in coffee and green tea, as well as alcohol,

can reduce moisture in the body

and make your mouth even drier.

Smoking is also a major contributor to dry mouth.

4. Pay attention to indoor humidity

Especially if you sleep with your mouth open,

turn on a humidifier and keep the indoor humidity

comfortably maintained at 50–60%.

“My mouth is a little dry.

It should be fine, right?”

Many people leave it untreated,

only to develop several cavities within a few months

or experience a sudden worsening of their gum health

before visiting a dental clinic.

If your mouth keeps becoming dry, do not leave it untreated.

Having scaling and regular dental checkups

at slightly shorter intervals than usual,

while managing your oral health carefully,

is a wise way to protect

your precious teeth.

I am Kim Geun-il,

director of 365 Seoul One Top Dental Clinic.

Thank you.

📍 365 Seoul One Top Dental Clinic

4th floor, Dongmyeong M Building, 179 Gangseo-ro, Gangseo-gu, Seoul

Magok implants / Gangseo-gu dental clinic / Hwagok-dong dental clinic

A 1-minute walk from Exit 8 of Hwagok Station