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Dental Fillings (Cavity Filling): Things To Know

Updated: Nov 13, 2023

Dental fillings are one option for restoring a tooth to it's normal form and function after having the decay removed. The cavity treatment does not end after simply excavating all of the decay.

Defective tooth filling
Defective tooth filling

The end result is a hole in your tooth, albeit a clean one but it would still need to be restored for proper function. Having the cavity filled back in with a tooth filling material is one method of doing so.

The entire procedure may seem foreign to you but it doesn't have to be that way. We will walk you through all of the steps involved for the treatment. We will also describe the various types of filling materials so that you know what you're getting. Last but not least, some of the complications that may arise from having this treatment done.

Table of Contents:

When is a filling needed?

The most obvious reason for needing a dental filling is if you have a cavity. Although you shouldn't forget that it is also a restorative dental procedure that can be used to repair small defects and imperfections.

decayed tooth
decayed tooth

When fillings are necessary:

  • Tooth decay. Small cavities will need to be removed and then filled back in to restore it to normal function. If you leave it unfilled, it will be sensitive and food can get stuck in it. Although the worse part is that the cavity can go and progress through the stages of tooth decay. As it does, treatment will grow in complexity and cost.

  • Recurrent decay. Teeth that have been filled can get cavities again! That is why you need to take care of them properly.

  • Small chipped tooth. A small chip on your tooth can be repaired by bonding a tooth colored composite to it.

  • Exposed dentin. Gum recession and enamel erosion may cause the dentin to become exposed. The end result is dentin hypersensitivity which can be extremely sensitive. The good news is that you can cover up the exposed dentin with composite bonding.

  • Missing fillings. Old fillings can de-bond and they may pop out while eating or while you're flossing. It can be quite sensitive when it is exposed.

  • Broken fillings. Restorations don't last forever so they do wear down over time.

  • Alter aesthetics. If veneers are out of your budget, you can try composite bonding to change the shape and color of your teeth. The downside is, they don't last as long as porcelain.

defective cavity filling
defective cavity filling

When a filling is not the proper treatment

A dental filling is not a miraculous procedure that can treat every tooth problem known to man. We have patients asking us all the time, "Can't you just put a filling in it?" Unfortunately we can't always do that because there are limitations in what it can do.

tooth split in half
tooth split in half

Here is a list of conditions for when you can't use a filling:

  • Tooth nerve pain. When an unhealthy or infected nerve is causing you spontaneous pain.

  • Abscesses and infections. Fillings will repair a hole but it will not drain an infection.

  • Large chips or breaks. If the tooth is missing more than 50% of its tooth structure, it will need more than a simple filling to repair it. A cavity filling would be insufficient treatment.

  • Cracked tooth. When a tooth is split in half into literally two separate teeth.

For these situations you would need other types of dental procedures such as root canals, tooth extractions, crowns, etc.

What to expect during a cavity filling procedure

For those who are curious and wish to know what to expect during a filling procedure, here are the steps.

  1. Administer local anesthesia. The numbing gel comes first, followed by the injection.

  2. Excavate decay. The carious tooth structure will need to be completely drilled out with a highs peed handpiece. Expect a lot of water, air, and noise.

  3. Apply conditioner. Typically a blue gel that contains acid etch, which conditions the tooth. It removes the smear layer and opens up the dentinal tubules.

  4. Apply primer. A hydrophylic monomer that wets and penetrates into the dentinal tubules. It creates a surface that the bonding agent can bond to.

  5. Apply bonding agent. The adhesive that bonds the tooth to the filling material.

  6. Place filling material. The filling material is placed into the cavity in layers so that it can be well adapted.

  7. Light cure to set. Each filling layer will need to be cured with a LED curing light that makes it harden. Without it, the material will stay soft and never set.

  8. Adjust the bite. The bite should be checked with articulating paper so that it doesn't feel high when you bite down. Biting pressure is often a result of an overfilled cavity.

  9. Polish. The surface of the restoration may feel rough after all of that adjusting. This is why it gets polished to make it smooth and glossy so it doesn't irritate your tongue.

You will be thoroughly numb for the entire procedure because it can be sensitive or painful to remove decay via drilling. The numbness should take about 2-3 hours for it to wear off so you will need to wait before you can eat.

How long does it take?

A single cavity filling should take about 30-45 minutes depending on how big the decay is. The smaller it is, the less time it will take. The reverse is also true in that the bigger it is, the more time it will take for your dentist to clean it out and fill it back in.

If you are filling more than one tooth, it will of course take more time. The time it takes will also depend on the clinician's experience and how large the decay is on each tooth.

  • Two teeth will take approximately 45 minutes.

  • Three teeth will take at least an hour.

Cavities that are in between the teeth will also require more time since it requires more set up. It involves an additional step of placing matrix bands to prevent the tooth from bonding to the adjacent one.

How long does it last?

Depending on the type of material the restoration is, it can last for many years. Although if it is not broken or causing any problems, you shouldn't replace it just because it is old.

  • Composites and amalgams can last up to 10 years or more if taken care of properly.

  • Gold will last for decades if cared for. Longevity wise, this is the best material of choice.

  • Ceramic such as porcelain will be somewhere in the middle between composites and porcelain in terms of durability.


Types of tooth filling material

Filling Material



Amalgam (silver filling)

Most affordable, good wear resistance

Metal colored, contains mercury

Composite resin (tooth colored filling)

Good aesthetics, bonded to your tooth, metal-free

Costs more than amalgam, bonding can be sensitive

Ceramic (porcelain filling)

Lasts longer than composites and amalgams, bonded on


Glass Ionomer (GI)

Cavity resistant

Poor wear resistance


Can last decades in the mouth, very biocompatible

Expensive, doesn't match your tooth color

The most common type of filling material used to be amalgam but over the past few decades, composites have overtaken them. A lot of that has to do with the advance in bonding technology which has enabled it to be the primary choice.

The public has also been shying away from having too much mercury in their mouth, which has decreased the popularity of the silver fillings. The other types of material such as ceramic, glass ionomer, and gold are options that are reserved for specific situations. They also tend to cost more as well.

Temporary filling

Temporary fillings are used as an intermediate step between procedures. They are not meant to be permanent and will be replaced by a different restoration after it has served its purpose.

Common situations where you may need one:

  • During a root canal. In between root canal visits and also before you get your permanent crown, you'll often have a temporary filling. This is placed instead of a permanent one because it is easier to remove which will save you time if you need to re-access the tooth.

  • Sensitive tooth. Sometimes a tooth that has been filled can be very sensitive. Your dentist can remove that filling and put in a temporary sedative filling to help calm it down. Once the tooth is no longer irritated you can get the permanent one.

  • DIY solution for a missing filling. It could be late Saturday night and your filling just fell out. There is no dentist open but pharmacies do sell temporary fillings that you can use to hold yourself over until Monday.

Direct vs indirect fillings

Fillings can be categorized as direct or indirection restorations. The former can be completed in a single treatment visit while the latter requires two appointments. The reason for the additional visit for indirect restorations is because the dental lab needs to make it.

While the lab is making the permanent filling, you will have a temporary one in your mouth. During the second visit, the temporary will be removed and the permanent one will be cemented in.

Direct fillings:

  • Amalgams

  • Composites

  • Glass ionomer

Indirect fillings:

  • Ceramic

  • Gold

However due to recent advances in dental technology, some indirect fillings can be milled chairside with CAD/CAM. That is a piece of equipment that will make the restoration in the dental office.

The advantage of using CAD/CAM is that it decreases the number of visits down to one. The downside is that it does make the appointment take about an hour longer.

Taking care of your new filling

One of the best things about cavity fillings is that you don't need to do anything special to take care of them. You can simply treat them as if they were any other tooth in the mouth.

This means that good oral hygiene practices apply to them as well:

  • Brush for at least two minutes twice a day with a remineralizing toothpaste.

  • Floss before you go to bed.

  • Use a mouthwash.

  • Minimize the amount of sweets and low pH foods.

You can speak, chew, and eat like you normally do. You can even kiss your significant other afterwards but that is only if you do it lightly. Drinking (water, beverages, alcohol) is okay but you may want to wait for the anesthesia to wear off so you don't spill it on yourself.

However the only precaution we would make is to be careful eating very hard foods. Biting into crab legs the wrong way will break your regular teeth and teeth with fillings are no exception.

Post-operative complications

We all wish that things go perfectly every time but unfortunately can problems arise during the procedure or even afterwards. That is a fact of life that is unavoidable.

Dental filling complications:

  • Sensitivity. It isn't unusual for your tooth to be sensitive for the next day or two after the procedure. After all your dentist did drill away a piece of your tooth. Imagine if someone removed a part of your arm, it would certainly be sore and tender for a few days.

  • Biting pain. If the tooth was overfilled, you may end up with an uneven bite that feels off. The fix is simple in that your dentist needs to adjust the bite.

  • Voids in filling. Sometimes the filling isn't packed in tightly enough during condensation. This may cause voids or air bubbles to form in the filling which may cause sensitivity.

  • Pulpitis. The cavity removal process involves a high speed handpiece that rotates quickly and generates a lot of heat. The nerve of the tooth can become irritated and inflamed after the procedure. Sometimes it'll heal on its own and other times it doesn't.

  • Broken. You're not supposed to eat immediately after the procedure because you're numb. However if you did not follow directions and bit into hard food the wrong way you can crack the filling.

  • Allergy. It may be rare but it is possible to be allergic to amalgam and composite fillings.

  • Feeling sick. You may feel unwell after the procedure and experience a headache, sore throat, or even heart palpitations.

  • Bruising. Bruising is a potential complication after a cavity filling which results from the penetration of the dental needle.

Dental filling allergy

There was a systematic review that searched through the entire research database from 1928-2014 for studies and case reports about dental material allergies. It appears that composite resin filling allergies are very rare. Amalgams were a bit more common but still significantly below what latex and local anesthesia allergies are.

Type of Allergy








Local anesthesia


Just to be clear the allergy to silver fillings seems to stem from the mercury in them. Therefore if you're having a reaction to your amalgams, you most likely cannot tolerate mercury either. However... not to throw a monkey wrench at you, it is also possible to be allergic to the silver, copper, tin, or zinc in the amalgam as well.

Are silver fillings safe?

According to the FDA, the majority of research shows that exposure to mercury from amalgam fillings have shown no adverse health effects. They also do NOT recommend replacing them just because you don't want to have mercury in your mouth. Doing so will cause loss of tooth structure as well as exposure to mercury vapors during the removal process.

amalgam filling

The most amount of mercury exposure for amalgam fillings is during initial placement and also during its final moment of removal. Therefore it is actually more dangerous to remove them than to keep them in your mouth.

In case you were wondering, the silver filling is an amalgam of various metals hence where its name came from! The mercury is used to bind all of the components together to form a sturdy stable filling.

Insurance coverage

The vast majority of dental insurances should cover dental fillings. In our experience, most PPO dental insurances classify it as a basic procedure with an 80% coverage rate. That means you will be responsible for a 20% copayment.

However the coverage percentage may vary depending on the plan that you signed up for. We have seen insurance plans which have 100% coverage and also some that will cover 50%. It all depends on the plan that you choose so read the terms of the contract carefully before you sign it.

Last but not least, one more thing to watch out for is if your plan has any downgrades. Some plans will not cover the more expensive tooth colored composite fillings. Instead they will downgrade you and reimburse your dentist at the level of an amalgam filling which costs less.

The end result is that you will be responsible for the difference. That is just one fine print item which may add to the cost of your visit. Most modern dental offices have been steering away from using the silver fillings due to the public being health conscious about mercury.

Cost without insurance

The cost of a tooth filling will vary greatly depending on the type of material and how many surfaces it covers. As an example we'll give you the average price for composite fillings without insurance according to the 2022 ADA survey of dental fees.

  • 1 surface posterior composite = $208.07

  • 2 surface posterior composite = $264.97

  • 3 surface posterior composite = $319.82

  • 4 surface posterior composite = $377.29


Dental fillings are used to restore a tooth back to its normal form and function after it has been decimated by tooth decay or other means. It does a very good job at that but it is limited in what it can repair. It is mostly meant for repairing small cavities and defects.

Larger cavities and defects would require a different dental treatment. However the point that we want you to take away from this is to not leave problems unaddressed because they will grow. If a condition could've been treated by a filling but you left it alone, it may not be a filling anymore a few months later! This is why it is important to stay on top of your dental check ups.



David Chen 200 x 200.jpg

About the author: Dr David Chen, DDS

Hello, I'm Dr Chen and I'm an actively practicing dentist in Long Island City, NY. I graduated from Columbia University College of Dental Medicine in 2016 but prior to going to dental school I was already working in the dental field. It's been more than a decade since I first got to know dentistry and let me tell you, time flies by quickly. Since then I've developed a fondness for writing, which is how this all got started!

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Medical Disclaimer:

This blog is purely meant for information purposes and should not be used as medical advice. Each situation in your mouth is unique and complex. It is not possible to give advice nor diagnose any oral conditions based on text nor virtual consultations. The best thing to do is to go in person to see your dentist for an examination and consultation so that you can receive the best care possible.

The purpose of all of this oral health information is to encourage you to see your dentist and to inform you of what you may expect during your visit. Due to the unfortunate nature of dentistry, there isn't really any true home remedies that will get rid of dental problems. Roughly 99.99% of them require in-person intervention by a healthcare professional.

Hint: That is the reason why you can't eliminate seeing dentists in your life!

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