When You Need a Dental Filling + What to Expect

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Hi, I’m Dr. B, practicing functional dentist for 35 years. I graduated from the Dugoni School of Dentistry in San Francisco, CA in 1987 and am a member of the American Academy of Dental Sleep Medicine (AADSM), Academy of General Dentistry (Chicago, IL), American Academy for Oral Systemic Health (AAOSH), and Dental Board of California. I'm on a mission to empower people everywhere with the same evidence-based, easy-to-understand dental health advice that my patients get. Learn more about Dr. B

For a small-to-medium cavity that needs dental attention, your dentist may recommend a dental filling. This virtually painless procedure is a great way to preserve your living tooth structure while removing decay that’s set in.

Some of the most common questions I get about fillings include ones such as these:

  • How do I know if I need a filling?
  • Should I have amalgam (silver) fillings removed?
  • Does it hurt to get a filling?
  • How many times will I need to go to the dentist for my filling?

First of all, don’t worry! Getting or replacing fillings is one of the most painless dental procedures.

Also, there’s a lot of confusion online about which types of fillings to consider. We’ll cover that in detail so you can go to your next appointment with more confidence and less concern.

Let’s look at what dental fillings are, what to expect when you get a filling and other common questions.

What is a dental filling?

A dental filling is a dental procedure used to restore part of a tooth that has been damaged by decay.

The objective with a filling is to remove the decayed area, clean it well, and “fill” the space with a material, returning the tooth to its normal shape and, hopefully, normal function.

There are a number of materials that can be used for a tooth filling. Amalgam (silver colored), composite (white, or shaded to match the color of your remaining teeth), and gold are the most common materials used. Porcelain fillings are another option that can have you in and out in just a visi

How does my dentist know I need a filling?

The most tell-tale signs of a cavity or decay are pain or sensitivity around the affected area or food suddenly getting caught between teeth. You should call your dentist as soon as you feel pain or when cold drinks or hot foods cause you to jump with discomfort or tingling.

Because pain occurs when a cavity is already fairly large, it’s important to be seen quickly when you feel pain. Most dental professionals leave time in their schedules for emergency appointments.

Don’t settle for using numbing agents like clove oil or Orajel and ignore your tooth pain. Schedule an appointment right away for sharp or throbbing tooth pain in one or just a few teeth.

When you get to the dentist’s office, s/he will perform some simple tests.

Visual Assessment: Your dentist will do a visual assessment and look around your mouth, most carefully around the area where you complain of pain. At this point, s/he is looking for the most obvious signs of a cavity: cracks, discoloration, white colored lesions, or even rough parts or “spots” on the outside of your teeth.

Probing/Palpation: After visual assessment, your dentist will then probably use a small instrument to gently tap on and poke your teeth. The instrument is like a small pick. Different kinds of decay will feel differently to the pick. This is another way to determine the severity of your tooth decay. The sharp point engages the decayed dentin and makes a pinging sound when pulled away from it. Dentist call this a “stick.” As a patient, you can hear and feel the tug of the engaging dental explorer, called the pick.

This palpation is effective in finding occlusal decay, which is a cavity/decay on the top or exposed sides of teeth. However, it can’t detect interproximal decay, meaning cavities/decay between the teeth.

Probing with visual assessment can also help the dentist identify other teeth that may need further examination or a problem not even related to cavities. For example, pain in the area around an upper tooth may actually be coming from decay in a lower tooth. This is called “referred pain” and can lead to an erroneous diagnosis.

There are several medical issues that can cause pain in and around your teeth other than decay. Referred tooth pain may be due to problems with your heart or lungs, respiratory illness, or even neurological conditions. (1) For example, the roots of your upper teeth are close to your sinus passages, a sinus infection or inflammation may cause pain or discomfort in your teeth.

X-Rays: After the dentist finishes a visual examination and has palpated around the inside of your mouth, s/he will most likely have a set of dental x-rays taken. These images give the most in-depth look at your teeth. They allow the dentist to determine if there is, in fact, a cavity, as well as the size and severity of any cavities present.

An x-ray will give your dentist the most accurate picture of what’s needed when deciding between a filling or a more drastic treatment, like a root canal.

Diagnosis and Treatment Plan: At this point in the examination, you will be given a synopsis of the dentist’s findings and a course of action.

If I review a patient’s findings and discover a very small area of decay in the enamel (not dentin), I may recommend a plan for remineralization, or healing cavities naturally. There may be a chance for remineralization if the patient can keep the area clean and follow a straightforward diet plan with foods to reverse cavities.

However, the cavity may be too large to fill or located in an area of the mouth where the patient would have difficulty keeping it clean. Or, I may know the patient’s diet is not conducive to remineralization. In these cases, I would proceed with a dental filling.

Types of Dental Fillings: What kind of filling should I get?

Amalgam: Possibly the most commonly seen in adult mouths, silver/amalgam fillings are the go-to for most dentists. While the FDA states that dentists have been using this material for more than 150 years and it’s totally safe, I suggest steering away from this option.

Amalgam fillings start out very shiny silver in appearance (certainly not something most folks would want used on the front teeth), but turn to a dull gray or even balck color over time. This happens because silver is a corroding material. Still, amalgam is a popular choice because of its relatively low cost and easy placement in a wet field.

The 2 most important reasons I can’t recommend them are these: the process involved in getting “silver teeth,” and the chemical composition of amalgam fillings.

  1. The process. If you have a very small cavity, your dentist will have to cut away perfectly good tooth to make the design of the metal filling better. I don’t like to remove portions of a perfectly healthy tooth for any reason.
  2. The composition. According to the FDA, dental amalgam is “a mixture of metals, consisting of liquid (elemental) mercury and powdered alloy composed of silver, tin, and copper. Approximately 50% of dental amalgam is elemental mercury by weight.”

Although many experts state that this level of mercury in the filling is safe, I do not recommend it. With other, less problematic dental filling options to consider, it seems an unnecessary risk to me.

If you do have amalgam fillings, you should expect them to last about 10-15 years before being replaced. Be sure to work with a dentist who has experience and proper equipment for mercury removal (more on how to find those dentists here).

Composite resin (or plastic): Composite fillings are usually composed of glass and acrylic resin. These are a popular choice for front teeth that are clearly visible because they can be easily matched to your natural teeth color (sort of like porcelain crowns). Composites are also more cost-effective than our fourth option below, gold.

However, this type of dental filling may not be for you. Composites aren’t as durable as some of the other more common options, and therefore, don’t last as long (generally speaking, between three and 10 years). They are best suited for smaller cavities.

Another downside to consider is that composites can be difficult to polish. They can also be stained by tobacco use and coffee or wine. The newer composites are better at resisting this.

Porcelain: While not the most expensive of the top types on the market, porcelain fillings typically require more than one visit to complete.

It’s becoming more mainstream to use newer techniques where the filling is “milled” (shaped) while the patient waits, finishing everything in just one visit. However, these fillings are bonded to the teeth with composite materials, which can fail quicker than the porcelain itself.

  1. You must be fitted for porcelain fillings (also known as inlays or onlays). Then, an impression is sent to an outside lab to fabricate the inlay.
  2. You’ll make the second appointment to have the filling bonded to the tooth and checked for fit and function.

Like composites, porcelain can be matched to the color of your teeth, but they are much more resistant to stains from tobacco, coffee, and tea. And while they’re not as hard-wearing as gold and silver, they look the most like natural teeth.

Gold Inlay/Onlay: Last of the most common filling materials I want to mention is the gold inlay/onlay. Its durability and long-lasting quality make it a great choice for dental fillings. Although many people prefer their fillings to blend in with their natural teeth, this is a very good, cost-effective, and safe option.

Even though the filling is visible, this material is very well tolerated by gum tissue and opposing teeth (which is why it’s so durable). It also wears down at a rate that won’t upset your bite during its lifetime.

Technically, gold inlays and onlays aren’t actually “fillings,” but castings. With the other materials, your tooth is cleaned out and the material is poured in. However, gold must be cast from a mold of your teeth.

It isn’t unusual for gold fillings to last 40 years and beyond. The process of inserting the gold inlay or onlay requires two visits, so you should plan for more than one visit to the dentist to complete this procedure. Gold inlays/onlays are significantly more expensive up front, but very cost-effective over time.

dental fillings

What to Expect When You Get a Dental Filling

Ready to get a dental filling? Here’s what to expect.

Numbing the area. First, you’ll receive an injection of local anesthesia. After the shot, you’ll likely be left alone for up to 10 minutes while the medicine takes effect.

This is the most painful part of the procedure—once you’ve endured the injection, the pain is mostly over.

Removing the decay or old filling. Once the area around your decayed tooth is completely numb, your dentist will use a handpiece to clean out the space where the cavity (or old filling) is located. It’s very important that the entire area is cleaned out very well, especially if you’re having an old filling removed.

Designing and inserting the new filling. The dental filling will then be designed according to the size, shape, and angles where the decay was removed.

When inserting a plastic filling, it isn’t necessary to remove any part of the tooth other than what is decayed or damaged. Your dentist will create line angles and clean edges for a well-fitted filling. Amalgam fillings require the removal of more tooth material in order to fit properly.

*Keep in mind that, for gold inlays/onlays, you’ll probably need to come back for a second visit after the material has been cast.

If the cavity is between two teeth, the dentist must stretch a small band around one of the teeth. Otherwise, when the filling material is syringed into the area, the teeth would be glued together, preventing flossing and proper cleaning.

Before syringing the filling into the space, I condition the tooth. There are three steps here, which were done in separate steps when I was in dental school. Now, they are all done together: acid etch, primer, and bonding agent. This conditioning agent is administered to the tooth with a small, round sponge.

The band used as a separator is called a Tofflemire band or a matrix band. For the purposes of this article, I’ll call it the matrix band. Once the matrix band is placed, the filling can be syringed in.

Then, the material is hardened with a small handheld device called a curing light. This process is called light polymerization. The dental filling is set when it’s exposed to a certain wavelength of light.

Once the work is carefully checked, the matrix band can be removed. The filling is then cured again since the band was covering part of the exterior filling area. At this point, only two more steps remain.

Polish and Bite Check: Now, the dentist can carefully polish the filled area until smooth and properly shaped to fit in well with the teeth around it. Finally, your dentist will perform a “bite-check” to ensure the new filling is not hitting the opposing teeth poorly.

If your bite is not correct, you’ll end up with more tooth pain from improperly touching teeth when you chew. This is one reason patients sometimes have to see the dentist again soon after a filling.

How long does a dental filling last?

Different dental filling materials will last different lengths of time, although how you care for your teeth plays a part, too.

  • Amalgam (silver metal) fillings should last 10 years on average. However, I’ve seen them hold well for 15 and even up to 30 years.
  • Composite resin (plastic) fillings should last 3-10 years. There are cases where a plastic filling will last 20 or 30 years, but this is rare.
  • Porcelain fillings last 10-15 years.
  • Gold onlays/inlays are super durable and can be expected to easily last 40-60 years.

There are a number of factors that will impact the life of your filling, like these:

Keep up with good dental hygiene. How do you take care of a dental filling? The same way you take care of a tooth: All the usual steps of good oral care apply. That means you should floss, brush, eat a well-balanced diet, maintain a healthy microbiome, and manage your biofilm.

Pay attention to signs of grinding or bruxism. If you grind your teeth, especially at night, you can break dental fillings or wear them down prematurely. If you find yourself with some of the symptoms described in this article on grinding teeth, be sure to discuss it with your dentist right away.

Remember a filling isn’t a natural tooth. The simple answer to the question, “How long do dental fillings last?” is this: There is no simple answer.

A filling will not last forever. It’s a man-made substance, and will never be as good as what you were born with—good old enamel.

Fillings are made using a mixture of two different materials: man-made and natural. This is because it’s difficult to get the materials to shrink and/or expand at the same time, whereas dentin and enamel grow naturally with these coefficients of shrinkage expansion.

In other words, the filling may not fall apart, and the tooth may never develop recurrent decay, meaning cavities in the living part of the tooth. However, as long as filling materials expand and contract at different rates of speed from your original tooth, tiny micro fractures can happen.

During your dental cleanings, your dentist can keep an eye on the state of any dental fillings you have. S/he will be able to tell you when they need to be replaced.

What To Do About Amalgam Fillings

As I noted earlier, amalgam (silver) fillings are composed of 50% mercury. However, it’s true that amalgam fillings have been in use for 150+ years and, for many people, cause no side effects.

In some people, though, mercury can cause tooth sensitivity. (2) Plus, if you’re exposed to mercury/amalgam on a regular basis, toxicity may be a concern.

Removing and replacing amalgam fillings can be costly and actually expose you to more mercury (in the short term) than you would be otherwise. For most people concerned about amalgam toxicity, it’s a good idea to simply practice simple detox methods to limit your mercury exposure.

Chelation therapy is a treatment for detoxification of heavy metals in the body. The treatment circulates a chelating solution that binds the toxins in the bloodstream.

You should also eat plenty of cilantro.

Yes, you read that correctly: cilantro. Simply eating cilantro multiple times a day can be extremely effective to naturally detoxify the body of the possibly harmful effects of heavy metals. Research indicates it’s not only effective but also simple and inexpensive. (3)

You might ask, “What if my dentist only offers amalgam fillings?”

My first answer would be to consider a different dentist. Composite resins and porcelain fillings are much safer for your mouth and body.

Another question I’m asked a lot is, “What should I do if safer options like porcelain or composite (or even gold, for that matter) are too expensive for my budget, or my dental insurance has cost caps for other filling materials?”

If the cost of a dental procedure is more than you can reasonably afford, I would suggest you visit a dental school.

Any treatment you receive there is carefully and closely monitored by highly qualified dentists serving as instructors. The cost of their services is lower than what you’d pay in a traditional dental office.

Frequently Asked Questions About Dental Fillings

dental fillings

Q: What’s the difference between a dental filling and a root canal?

A: A dental filling is used to replace (fill) a space where decay or damage has occured in a tooth. The root of the tooth remains intact and still sends blood flow to the tooth structure. The tooth can still be remineralized and demineralized.

When you need a root canal, the decay has progressed to a point that the entire root must be cleaned out. The tooth left behind is “mummified” and no longer has blood flow. It will need a crown and runs the risk of future infection that could require the tooth to be extracted, although many people have successful root canals that allow them to preserve tooth structure.

As I outline in greater detail in the article, “Know Before You Go: Root Canals,” this procedure is done to preserve your tooth. By the time a root canal is recommended, it’s typically too late to save the life of the tooth; it is already too infected and has begun to die.

During the initial procedure, the inflamed pulp is removed and the inside of the tooth is carefully cleaned out and shaped. Then, the space is filled and sealed. At the second visit, a crown will be placed on the tooth to protect it from breakage, since the mummified tooth will become more brittle over time.

Q: Will I ever need a filling with a crown?

A: I get this question often, and it’s a great one to ask. Although a dental crown is quite a bit more expensive than a filling and requires an additional visit to the dentist, sometimes, it is completely necessary.

A dental crown covers teeth after damage or cosmetic issues, including root canals as well as large fillings and even certain cases of broken teeth.

The actual crown is a cap made of inanimate material (usually porcelain or gold). It is shaped to look like and fit onto a tooth so that the inside of the tooth isn’t exposed.

The general rule of thumb to determine the need for a crown is this: if it’s determined that the width of the dental filling (or the space cleaned of the decay, or removal of the previous filling), is greater than ⅔ width of the tooth, then you’ll most likely require a crown.

Think about it like this for a moment: If the cavity has taken over the majority of your tooth until all that is left is the thin outer wall of the tooth, it wouldn’t take much normal use to crack or break it. Then, your dental problems (and your dental bills) will increase even more.

To prevent breakage, large fillings like I described will be paired with a crown.

Q: Does filling a cavity hurt?

A: There are several aspects to consider when answering this question.

I can safely say that most of my patients don’t feel anything when a filling is done. If you respond well to the numbing process and the procedure is done without complication or incident, you should have a relatively pain-free experience.

Here are some instances where “typical pain” can occur:

  • Sometimes, the injection to number the area is not given properly. In these cases, a little internal bleeding or small hematoma could form inside.
  • If, while trying to find the “perfect” location for the anesthesia, the dentist bounces off or accidentally touches the bone, you’ll probably feel pain. This pain is usually dull and achy around the bone.
  • If a matrix band is placed around the tooth incorrectly, it could slip down below the gum and scrape or cut it.
  • Another way the gum feel pain is if it gets nicked (by accident) during the filling procedure. I’ve found that gum pain can be pretty tough to deal with.
  • Desiccation (the drying out of a tooth) can also cause pain. This can happen when too little water spray is used, which allows the affected area to overheat. Or, the dentist can blow too much air in the tooth and desiccate it that way.
  • After a procedure where your mouth had to remain open for a long period of time, you could experience some jaw pain or discomfort. And if you’re a frequent bruxer/grinder, your “masters,” or chewing muscles, are going to be a bit of a mess anyway. This can be easily prevented by using a bite block, which props the mouth open without forcing the patient to strain jaw muscles. In essence, the bite block does all the work.

That may seem like a long list, but all of these are somewhat rare complications of a dental filling procedure.

If you have a good dentist with a clean office and high-quality staff, your experience with a dental filling should be fairly painless. What I like to hear from patients at their next cleaning after a dental filling is, “I just had a little bit of soreness.”

Q: What does a dental filling look like?

A: This may sound over-simplified, but the actual appearance of a filling in your tooth should just look a substance filling the cleaned-out space in your tooth. It is extremely important to trust your dentist to work carefully to fashion, shape and smooth your new filling to the exact shape of your natural tooth.

This isn’t just for the sake of aesthetics, though. Your bite has to be returned to the same line as it was before you had a cavity. Otherwise, you’ll be back to the office in the near future with a new kind of pain due to a misaligned bite.

Chewing with a badly lined bite can cause teeth to bang against each other, potentially damaging other teeth. You also run the risk of issues occurring such as temporomandibular joint disorder (TMD, TMJ).

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Q: How much does a dental filling cost?

A: According to NerdWallet and Member Benefits, the average cost of fillings is:

  • Amalgam (silver): $132
  • Resin composite (white): $155-170
  • Porcelain (white): $1400-1600
  • Gold inlay/onlay: $1123-1600

Keep in mind that this varies depending on where you live and where the tooth is located in your mouth (harder-to-reach teeth cost more). If you gasped a little when you saw the cost of porcelain fillings or gold inlays/onlays, remember that those last significantly longer than the cheaper options and/or don’t involve toxic materials within the mouth.

For lower-cost fillings procedures, try contacting a local dental school.

Q: Does a filling stop cavities from forming in that tooth?

A: The correct answer depends on the type of material you choose for your filling.

In the case of metal fillings, you may have some corrosion in the mouth. As odd as it may seem, that’s how the metal tooth filling maintains its record of longevity. As the filling material is corroding, it’s filling in that gap.

Without getting too technical, the corrosion byproducts of the filling are killing the bacteria that try to attack that interface between filling and tooth. So it’s the inherent weakness of the filling, ironically, that’s keeping it in there longer, because bacteria really don’t have a chance of causing recurrent decay as the metal corrodes.

Composite resin fillings are very different. They are sealed against the tooth, but that seal will break down eventually. There’s also no possible corrosion by-product to maintain or eradicate the naturally occurring bacteria. That’s why recurrent decay is a little more common with composites.

Key Takeaways on Dental Fillings

Of all the information I’ve provided in this article regarding dental fillings, what are the most important things to remember?

First, don’t ignore sharp or throbbing pain in one or a few teeth. It’s tempting to self-treat this type of pain and wait until you can “afford” dental work, but the longer your cavity has to take root, the more chances you’ll have a more expensive procedure ahead.

Second, make sure you understand your options. Whether it’s the choice between a root canal or a dental filling or just selecting the right material for your dental filling, ask for thorough information about the options you have.

Third, remember that fillings are almost always virtually pain-free. The worst part of just about every dental filling is the injection at the very beginning when your dentist numbs your teeth.

Want to know more about the process of getting a filling? Just ask me.

Learn More: 7 Questions to Ask Before Agreeing to Any Dental Procedure


  1. Ehrmann, E. H. (2002). The diagnosis of referred orofacial dental pain. Australian Endodontic Journal, 28(2), 75-81. Abstract: https://www.ncbi.nlm.nih.gov/pubmed/12360674
  2. Rathore, M., Singh, A., & Pant, V. A. (2012). The dental amalgam toxicity fear: a myth or actuality. Toxicology international, 19(2), 81. Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3388771/
  3. Sears, M. E. (2013). Chelation: harnessing and enhancing heavy metal detoxification—a review. The Scientific World Journal, 2013. Full text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3654245/