Risks of dental treatment explained

Reviewed by Dr. Samar Fadavi, DDS

Short answer: Every dental treatment, like every medical treatment, carries some risk. Most risks are small, temporary and manageable, such as sensitivity after a filling or swelling after an extraction. Serious complications are uncommon. Your dentist should explain the benefits, risks and alternatives of any treatment, including the risk of doing nothing, so you can make an informed choice.

Why talking about risk matters

Modern dentistry is very safe, but no treatment is entirely without risk. Teeth, gums, bone, nerves and sinuses are all close together, and every person heals differently. Understanding what could happen, how likely it is and what can be done about it helps you make decisions with confidence and know what is normal during recovery.

In Ontario, dentists must obtain your informed consent before treatment. That means explaining what they recommend, why, what the other options are, the main risks and benefits of each, and what may happen if you choose not to treat. This guide gives an overview of common risks for everyday treatments, how risks are reduced, and questions to ask. It is general information for patients in Scarborough, the Danforth and East Toronto, and your own dentist will explain the risks that apply to you.

Informed consent: your right to understand

Consent is not just a signature. It is a conversation. A good consent discussion covers:

• What the problem is and how it was diagnosed.
• The recommended treatment and how it is done.
• Other reasonable options, including no treatment.
• The expected benefits and how long the result may last.
• Common risks and rare but serious risks.
• What recovery involves and what is normal.
• The estimated cost and how insurance or CDCP may apply.

You can ask questions, take time to think, ask for information in writing and change your mind before treatment starts.

Risks of common treatments

Local anesthetic (freezing)

Possible effects include a brief fast heartbeat, soreness or bruising at the injection site, a stiff jaw after a lower injection and, rarely, numbness or tingling of the lip or tongue that lasts longer than expected. Biting a numb lip or cheek is a common avoidable injury, especially in children. Our dental anesthesia guide explains more.

Fillings

• Sensitivity to cold, hot or biting for a few days to a few weeks.
• A filling that feels high, which is quickly adjusted.
• Deep cavities near the nerve may later need a root canal, even after a good filling.
• Fillings can chip, wear or leak at the edges over time.

Crowns and bridges

• Sensitivity while wearing a temporary crown.
• A temporary crown coming loose.
• The tooth under a crown may later need a root canal, especially if it had a large filling or deep decay.
• Porcelain can chip, and crowns can loosen over the years.

Our crowns and bridges page explains these treatments.

Root canal treatment

• Tenderness for a few days after treatment is common.
• A flare-up with swelling can occasionally happen and may need medication or extra care.
• Some teeth have hidden canals or curved roots that make treatment harder, and some need retreatment later.
• Treated back teeth can become brittle and crack, which is why a crown is often recommended afterward.
• Rarely, an instrument can separate inside a canal.

Our root canal page explains the treatment.

Tooth extractions

• Bleeding, swelling and soreness for a few days are expected.
• Dry socket, a painful condition when the blood clot is lost, can occur a few days later, more often after lower wisdom teeth and in smokers.
• Infection of the socket.
• Damage to nearby teeth or fillings.
• For lower wisdom teeth close to the nerve, temporary or rarely lasting numbness of the lip, chin or tongue.
• For upper back teeth near the sinus, an opening into the sinus that usually heals but sometimes needs repair.

Our tooth extraction page and wisdom teeth guide explain what to expect.

Dental implants

• Swelling, bruising and discomfort after surgery.
• Infection around the implant.
• The implant may not bond with the bone and may need to be removed and replaced later.
• Gum and bone problems around the implant over time, called peri-implantitis, especially with smoking, diabetes or poor cleaning.
• Rarely, nerve or sinus involvement, which is why careful planning with 3D imaging is used.

Our dental implants page explains planning and care.

Orthodontics (braces and aligners)

• Soreness for a few days after adjustments or new aligners.
• White spots or cavities around brackets if cleaning is poor.
• Gum irritation and, rarely, gum recession.
• Slight shortening of tooth roots in some people.
• Teeth shifting back without a retainer.

Our guide to braces and aligners covers daily care.

Teeth whitening

Temporary tooth sensitivity and gum irritation are the most common effects. Whitening does not change the colour of fillings or crowns, which may then need replacing to match. Our tooth whitening guide explains more.

Cleanings and gum treatment

Temporary sensitivity and tender gums are common after a deep cleaning. As inflamed gums heal and shrink, spaces between teeth can look slightly larger.

Dentures

Sore spots, difficulty eating and speaking at first, and gradual loosening as the gums change are common. Our dentures guide explains adjustments and relines.

Factors that can raise risk

• Smoking and vaping, which slow healing and raise the risk of dry socket, infection and implant problems.
• Uncontrolled diabetes, which slows healing and raises infection risk.
• Blood thinners, which can increase bleeding. Most treatment goes ahead safely with extra steps.
• Certain bone medicines, which can rarely affect healing after extractions or implants.
• Heart conditions that may need a preventive antibiotic. Our guide on antibiotics before dental work explains who needs one.
• Radiation to the head and neck, which affects healing of the jaw bone.
• Pregnancy, which changes the timing of some treatments. Our pregnancy guide explains what is safe.

How risks are reduced

• A full health history and medication review before treatment.
• X-rays and, for complex cases, 3D imaging to plan around nerves, sinuses and roots.
• Careful technique, good isolation with a rubber dam where suitable, and sterile instruments. Our guide on infection control explains the steps.
• Clear aftercare instructions and a way to reach the clinic if you have concerns.
• Follow-up visits to check healing.
• Referral when a case needs more advanced care.

Steps you can take

1. Share your full health history, including medicines, supplements, allergies and past reactions.
2. Ask questions until you understand the plan, the options and the risks.
3. Follow pre-treatment instructions, such as taking a prescribed antibiotic or eating before your visit.
4. Follow aftercare instructions closely, especially after extractions and surgery.
5. Avoid smoking before and after surgery as long as you are able.
6. Keep follow-up appointments.
7. Call the clinic if pain gets worse instead of better, swelling increases after the third day, or you have fever.

What to avoid

• Do not hide medicines or health conditions, even if they seem unrelated.
• Do not smoke, spit forcefully or drink through a straw after an extraction.
• Do not chew on a numb side.
• Do not skip the crown recommended after a root canal on a back tooth without discussing the risk of fracture.
• Do not ignore signs of infection after treatment.

The risk of doing nothing

Choosing not to treat is also a decision with risks. A small cavity can grow into a painful infection. Gum disease can lead to bone loss and loose teeth. A cracked tooth can split. An infected tooth can, in rare cases, cause spreading infection that needs urgent medical care. A good consent discussion includes these risks too, so you can weigh them against the risks of treatment.

Questions to ask your dentist

• What happens if I wait or choose not to treat?
• What are my other options?
• What are the most common side effects, and how long do they last?
• Are there any risks that apply to me in particular?
• What should I do if something feels wrong after treatment?
• How long should this treatment last, and how do I care for it?

Normal healing versus warning signs

It can be hard to know what is normal after treatment. As a general guide:

Usually normal

• Mild soreness or tenderness for a few days that improves each day.
• Swelling after an extraction or surgery that peaks around the second or third day, then goes down.
• Slight oozing of blood for the first day after an extraction.
• Sensitivity to cold after a new filling that slowly fades over a few weeks.
• A sore jaw from keeping your mouth open, which eases within a day or two.
• Mild aching of teeth for a few days after braces are adjusted or a new aligner is started.

Call the clinic

• Pain that gets worse after day three or wakes you at night.
• Swelling that keeps growing after day three, or spreads to the eye or neck.
• A fever, chills or feeling generally unwell.
• A bad taste or pus.
• Bleeding that soaks gauze quickly and does not slow with firm pressure for 30 minutes.
• Numbness that is still present the next day.
• A filling or crown that feels high, or a temporary crown that comes off.

Seek emergency medical care right away for difficulty breathing or swallowing, or swelling that is spreading quickly.

Second opinions

For larger treatment plans, it is reasonable to ask for a second opinion. A good dentist will not be offended and can send your x-rays and records with your consent. Hearing the same diagnosis twice can give you confidence, and hearing a different option helps you make a fully informed choice.

When to see a dentist

Call the clinic if, after any treatment:

• Pain gets worse after the second or third day instead of better.
• Swelling increases, spreads or affects your eye or neck.
• You have fever, a bad taste or pus.
• Bleeding does not slow with firm pressure.
• Numbness lasts much longer than expected.
• Your bite feels uneven after a filling or crown.

Our emergency dentist page explains same-day care, and our family dentistry page covers everyday treatment.

Questions about risks of dental treatment

Is dental treatment safe?

Yes, for the vast majority of people. Most side effects are minor and temporary. Serious complications are uncommon.

Why does my tooth hurt after a filling?

Mild sensitivity is common and usually settles within a few weeks. A bite that feels high should be adjusted. Lingering pain should be checked.

What is dry socket?

A painful condition after an extraction when the blood clot is lost. It is treated at the clinic with cleaning and a soothing dressing.

Can a root canal fail?

Most root canals succeed, but some teeth need retreatment or another option later. A crown helps protect back teeth.

Do I have to sign a consent form?

Consent may be given in writing or verbally, and what matters most is that you understand the plan. Ask questions at any time.

Can I change my mind about treatment?

Yes. You can withdraw consent before or even during treatment, and the dentist will make the tooth safe and discuss next steps.

Are older people at higher risk from dental treatment?

Age alone is not the issue. Health conditions and medicines matter more, which is why a full health and medication review comes before treatment.

Can I lower my risk of dry socket?

Yes. Avoid smoking, straws and forceful spitting for several days, follow aftercare instructions and keep the area clean as advised.

What should I tell the dentist before treatment?

Your health conditions, all medicines and supplements, allergies, pregnancy, past reactions to dental treatment and any worries you have.

Are dental x-rays a risk?

Digital dental x-rays use very low doses of radiation, and they are taken only when they help your care. The risk of missing a hidden problem is usually greater.

What if I have a reaction to a medicine after treatment?

Stop taking it and call the clinic or your pharmacist. For swelling of the lips, tongue or throat, or difficulty breathing, call 911 right away.

Who do I call after hours?

Call the clinic number for instructions. For severe swelling, trouble breathing or heavy bleeding that will not stop, go to the nearest emergency department.