How to Tell if You Have a Cavity: Signs, Symptoms & Why Early Detection Matters

Cavities are one of the most common dental issues worldwide, yet many people don’t realise they have one until the damage has already advanced. A cavity, also known as dental caries or tooth decay, is essentially a small hole in the tooth caused by bacteria breaking down enamel.

Left untreated, cavities don’t just cause discomfort—they can progress into severe dental pain, infections, or even tooth loss. The good news? If caught early, they can be treated with a simple filling, saving you time, money, and discomfort.

So how can you tell if you have a cavity? Let’s explore the warning signs, why early detection is important, and how to prevent cavities in the first place.

1. Tooth Sensitivity: An Early Warning Sign

Tooth sensitivity is often one of the first red flags. You may notice sharp, shooting pain or a lingering ache when eating or drinking something hot, cold, sweet, or acidic.

This sensitivity happens because the protective enamel layer is weakened, exposing the dentin beneath. The dentin has tiny tubules that lead directly to the nerve of the tooth, which is why cold or sugary drinks suddenly “zing” when they hit your teeth.

If you’re experiencing ongoing sensitivity—even if it comes and goes—it’s worth booking a dental check-up.

2. Toothache or Persistent Pain

A cavity that has progressed deeper into the tooth may cause a dull ache or even stabbing pain. This discomfort often worsens when chewing or biting down, as pressure irritates the affected area.

Unlike occasional sensitivity, a persistent toothache is a strong indicator of decay and should never be ignored. Left untreated, bacteria can spread into the tooth’s nerve, leading to infection and potentially requiring root canal treatment.

3. Visible Holes or Pits in Your Teeth

By the time a cavity is visible to the naked eye, decay has usually advanced. Cavities often appear as small holes or pits on the tooth surface. They may be hidden in grooves of molars or between teeth, which is why dentists use tools and X-rays to detect them.

Running your tongue over your teeth may also reveal a “rough spot” or uneven surface where decay has caused damage.

4. Dark Spots or Staining

Not all tooth discoloration is a cavity, but dark spots or unusual staining on a tooth can be a sign of decay. This is especially true if the spot seems to be growing or is accompanied by sensitivity or pain.

It’s always best to have a dentist examine any new or unexplained staining. Catching a cavity at this stage usually means it can be fixed with a quick filling.

5. Bad Breath or an Unpleasant Taste

A cavity creates a space where bacteria and food particles can collect, leading to ongoing bad breath or a constant unpleasant taste in your mouth.

If you’ve noticed your breath isn’t fresh even after brushing and flossing, it may be more than just poor oral hygiene—it could be a sign of decay.

6. Rough or Sharp Tooth Edges

As decay erodes tooth structure, it can leave sharp or jagged edges. You may feel this when running your tongue over your teeth or notice that food gets caught more easily in certain spots.

This weakening of the enamel makes the tooth more prone to chipping, which is another sign the tooth is compromised.

7. Swelling or Abscess (Advanced Cases)

When cavities are left untreated, bacteria can penetrate deep into the tooth and cause an infection. This can result in swelling, severe pain, or even a visible abscess (a pocket of pus).

This stage requires urgent dental treatment—not just to save the tooth, but also to prevent the infection spreading to other parts of the body.

Why Early Detection Matters

Cavities don’t heal on their own. Once decay begins, it only gets worse with time. Early detection means your dentist can treat the cavity with a simple, pain-free filling.

If decay progresses, more invasive treatments like root canals or tooth extractions may be needed. That’s why regular dental check-ups are your best defence—dentists can spot cavities long before you notice any symptoms.

How to Prevent Cavities

The best treatment for cavities is prevention. Here’s how to reduce your risk:

• Brush twice daily with fluoride toothpaste.
• Floss once a day to clean between teeth where brushes can’t reach.
• Limit sugary and acidic foods/drinks which fuel cavity-causing bacteria.
• Drink plenty of water, especially fluoridated tap water.
• Visit your dentist every 6 months for a check-up and professional clean.

At Renew Dental Lounge, we also use advanced digital technology to detect cavities early—sometimes even before they’re visible.

FAQ's

1. Can a cavity heal on its own?

No—once a cavity forms, it won’t go away by itself. Only a dentist can repair the damage.

2. How do dentists detect cavities?

Dentists use visual exams, dental tools, and sometimes X-rays to spot cavities—often before you feel any symptoms.

3. Does getting a cavity filled hurt?

No—modern fillings are quick, painless, and done under local anaesthetic for your comfort.

4. How long can I wait to treat a cavity?

The longer you wait, the worse it gets. Early treatment is simpler, less invasive, and less expensive.

5. Can children get cavities too?

Yes—cavities are very common in children. Regular check-ups, fluoride treatments, and healthy eating habits are the best prevention.

Book an appointment today

At Renew Dental Lounge in Upper Mount Gravatt, we're redefining what it feels like to visit the dentist. If you're searching for a dentist in Mt Gravatt, we're here to help you feel at home in your smile. From gentle family dental check-ups, emergency dentist treatment, through to cosmetic dentistry like teeth whitening, veneers and dental implants, every visit is built on trust, compassion and excellence.

Patients looking for a dentist in Brisbane southside (Upper Mt Gravatt, Mount Gravatt, Mansfield and Mount Gravatt East) choose us for our spa-like environment, advanced technology and human-centred care that eases anxiety and transforms confidence. No matter where you're starting from, we'll meet you exactly where you are, supporting you with clear advice and personalised treatment options. Book an appointment today.