An early cavity usually doesn’t feel like anything at all; as it grows, you may notice a brief, sharp twinge with sweets or cold drinks, then sensitivity when biting, and eventually a lasting or throbbing ache. Cavities are one of the most common dental problems in both kids and adults. Small ones are simple to fix with a tooth-coloured filling, but once pain becomes constant or wakes you up, the decay may have reached the nerve, which is more serious.
So if you’re poking at a tooth with your tongue wondering “is that a cavity?”, you’re asking the right question. The tricky part is that feeling is a late signal. By the time a cavity hurts, it’s usually bigger than you’d hope.
Dentists use several tools to find decay early, including X-rays and, in some clinics, laser dentistry for detection and gentle treatment of small cavities.
Kids often can’t describe what they feel, so regular visits for children dentistry are the best way to catch cavities in little mouths. For adults with large or deep decay, single visit crowns can rebuild a tooth in one appointment, and if something feels off right now, online booking is the quickest way to get it checked.
What is a cavity?
A cavity (dental caries) is a hole in the tooth caused by acid from bacteria. Plaque bacteria feed on sugars and starches, produce acid, and that acid dissolves the minerals in enamel. Over time, a weak spot becomes a hole that can spread into the softer dentin and eventually the nerve.
What does a cavity feel like at each stage?
| Stage | What’s happening | What you might feel | Typical treatment |
|---|---|---|---|
| 1. Enamel weakening | White chalky spot | Nothing | Fluoride, better habits; can reverse |
| 2. Enamel cavity | Small hole in enamel | Usually nothing, maybe rough spot | Small filling |
| 3. Dentin decay | Decay reaches softer layer | Sharp twinge with sweets, cold, or hot that fades quickly | Filling |
| 4. Deep decay | Close to the nerve | Pain when biting, lingering sensitivity | Larger filling, onlay, or crown |
| 5. Nerve involvement | Pulp inflamed or infected | Throbbing, spontaneous pain, wakes you at night | Root canal and crown, or extraction |
| 6. Abscess | Infection at root tip | Swelling, bad taste, constant pain, sometimes fever | Urgent treatment |
Common signs you might have a cavity
- A quick, sharp zing when eating sweets or drinking something cold
- Sensitivity to hot drinks that lingers more than a few seconds
- Pain when biting down on one particular tooth
- A rough edge or hole your tongue keeps finding
- Food getting stuck in the same spot
- Floss shredding or catching between 2 teeth
- Dark, brown, or black spots on a tooth
- Bad breath or a bad taste near one area
Cavity pain vs tooth sensitivity: how to tell the difference
| Feature | General sensitivity | Cavity |
|---|---|---|
| Where | Several teeth, often near the gumline | Usually one specific tooth |
| Trigger | Cold air, cold drinks, brushing | Sweets, cold, hot, biting |
| Duration | Brief | Can start brief, then linger as it grows |
| Visible change | Maybe gum recession | Spot, hole, or rough area |
| Improves with sensitivity toothpaste | Often | Usually not |
Both can happen together, and only an exam can tell for sure.
Where do cavities hide?
- Between teeth: invisible in the mirror, often found only on X-rays
- Deep grooves of back teeth: food and bacteria collect there
- Along the gumline: especially with gum recession
- Around old fillings and crowns: where edges have worn or leaked
- Under the gum on exposed roots: more common in older adults
Is a cavity an emergency?
Usually not. Book a visit within a week or 2 if you have mild sensitivity. Call sooner if:
- Pain lingers, throbs, or wakes you up
- Biting causes sharp pain
- A piece of tooth broke off
- You see swelling or a bump on the gum
Go to a hospital for swelling that spreads toward your eye or neck, trouble breathing or swallowing, or high fever.
What causes cavities?
- Frequent snacking and sipping sugary or acidic drinks
- Not brushing twice a day or cleaning between teeth
- Dry mouth from medications, vaping, or health conditions
- Deep grooves in molars
- Gum recession exposing roots
- Old, worn fillings with gaps
- Not enough fluoride
Do cavities feel different in kids and adults?
Children
Kids rarely say “I think I have a cavity.” Instead, you might notice them chewing on one side, avoiding cold treats, rubbing their cheek, or getting cranky at meals. Baby teeth have thinner enamel, so decay can reach the nerve faster than in adults.
Adults
Adults often notice cavities around old fillings or between teeth first, usually as a quick zing with cold or sweets. Many adults have no symptoms at all until a cavity is found on X-rays.
Older adults
Root cavities near the gumline are more common, especially with dry mouth from medications. These can feel like sensitivity at the gum edge or show up as soft, brownish areas.
Which foods and drinks cause cavities most?
| Higher risk | Why | Better swap |
|---|---|---|
| Soft drinks and energy drinks | Sugar plus acid | Water or sparkling water |
| Sweetened coffee sipped all morning | Constant sugar exposure | Unsweetened, or finish it in one go |
| Gummies, caramels, dried fruit | Stick in grooves | Fresh fruit, cheese |
| Crackers and chips | Starch breaks down into sugar and packs into teeth | Nuts, vegetables with dip |
| Sports drinks | Sugar and acid during long activity | Water for most workouts |
| Hard candy and mints with sugar | Long contact time | Sugar-free gum with xylitol |
How often you eat matters as much as what you eat. Every snack starts a new acid attack that lasts about 20 to 30 minutes.
How dentists diagnose cavities
- Visual exam with bright light and drying the teeth to reveal white or brown spots
- Gentle probing of suspicious areas
- X-rays to see between teeth and under fillings
- Detection tools such as laser fluorescence devices in some clinics
- Cold and bite tests if there’s pain, to check the nerve
How are cavities treated?
Remineralization
Very early white-spot lesions can be stopped or reversed with fluoride varnish, fluoride toothpaste, and diet changes.
Fillings
Decay is removed and replaced with a tooth-coloured material. Most fillings are done in under an hour.
Inlays, onlays, and CEREC crowns
For larger cavities, ceramic restorations protect the tooth. With CEREC technology, they can be designed and placed in a single visit.
Root canal treatment
When decay reaches the nerve, the infected pulp is removed and the tooth is sealed and crowned.
Extraction
For teeth too damaged to save, followed by options like implants or bridges.
What’s it like getting a filling?
- Numbing gel, then local anaesthetic
- Decay removal with a small drill or, in some cases, a laser
- Tooth cleaned and prepared
- Filling placed in layers and hardened with a blue light
- Shaped and polished to fit your bite
Most people feel pressure and vibration. Numbness wears off in a few hours.
Questions to ask at your check-up
- Do I have any early white spots that could be reversed?
- Are there cavities between my teeth on the X-rays?
- Are any of my old fillings leaking or worn?
- Would sealants or extra fluoride help me or my kids?
- How often should I come in, based on my cavity risk?
Ask to see your X-rays or intraoral photos. Seeing a small dark shadow between 2 teeth makes it much easier to understand why a dentist recommends a filling before you feel anything.
Myths about cavities
“If it doesn’t hurt, I don’t have a cavity.” Most early cavities are painless. Regular check-ups catch them before pain starts.
“Only sugar causes cavities.” Starchy foods like crackers and chips also feed bacteria. Frequency matters as much as type.
“Kids’ cavities don’t matter because baby teeth fall out.” Many baby molars stay until age 10 to 12, and infection can affect adult teeth underneath.
“Once you have a cavity, it can heal.” Only the earliest white-spot stage can be reversed. Actual holes need treatment.
How to prevent cavities
- Brush twice a day for 2 minutes with fluoride toothpaste.
- Clean between teeth daily.
- Limit snacks and sugary drinks between meals.
- Drink water, especially fluoridated tap water.
- Chew sugar-free gum after meals.
- Ask about sealants for children’s molars.
- Keep regular check-ups and cleanings.
Real-life scenarios
The floss clue. A patient noticed floss kept shredding between 2 molars. No pain. X-rays showed a small cavity between them. One 30-minute filling fixed it.
The cold zing. Another patient felt a sharp twinge with ice water on one tooth that faded in seconds. It was a moderate cavity. A filling stopped the sensitivity.
The night throb. A patient ignored mild sensitivity for months. When the tooth started throbbing at night, decay had reached the nerve. Root canal treatment and a same-day CEREC crown saved the tooth.
Finding a top dentist in Woodbridge
Cavity diagnosis and treatment should be done by licensed professionals registered with the Royal College of Dental Surgeons of Ontario (RCDSO) who explain findings clearly and recommend the most conservative option.
Columbus Dental Centre has been serving Woodbridge and the Vaughan community for over 26 years, trusted for family and cosmetic dental care. Patients searching for a top dentist in Woodbridge or a cosmetic dentist in Woodbridge can get smile design, dentures, bridges, CEREC crowns and veneers, oral surgery, fillings, root canal treatment, dental implants, teeth whitening, preventive care, children dentistry, and laser dentistry in one place.
New patients and CDCP patients are welcome. Visit Suite #201, 8333 Weston Rd, Woodbridge, Ontario, call +1 647-931-1100, or email columbusdentalcentre@gmail.com. Extended hours include Mondays 10:00 AM to 8:00 PM and Saturdays 9:00 AM to 4:00 PM.
This article is general information. Only a dental exam with X-rays can confirm whether you have a cavity.
Frequently asked questions
Can you feel a cavity with your tongue?
Sometimes. Larger cavities can feel like a rough spot or small hole. Many cavities between teeth can’t be felt at all.
Does a cavity always hurt?
No. Most early cavities are painless. Pain usually means the cavity has reached deeper layers of the tooth.
How fast does a cavity grow?
It varies from months to years depending on diet, saliva, fluoride, and hygiene. Cavities in baby teeth and exposed roots can grow faster.
Can I wait to fill a cavity?
Small cavities can sometimes be monitored if they’re in enamel only. Once decay reaches dentin, it’s best to treat it before it grows.
What does a cavity look like?
It can look like a white chalky spot, a brown or black stain, or a visible hole. Many cavities can’t be seen without X-rays.
Conclusion
Early cavities usually feel like nothing, then progress to sensitivity, pain on biting, and eventually throbbing.
Catching decay early means smaller, simpler treatment.
Regular check-ups with X-rays find cavities long before you feel them.
