A dental filling typically takes 20 minutes to an hour, depending on the size and location of the cavity. The process follows a predictable sequence: numbing the area, removing decay, placing the filling material, hardening it, and adjusting your bite. Here’s what each step actually feels like and why it’s done.
Numbing the Tooth
The appointment starts with a local anesthetic, usually injected into the gum tissue near the affected tooth. Before the injection, your dentist may apply a topical numbing gel (typically benzocaine) so you feel less of the needle itself. The injectable anesthetic, most commonly lidocaine or articaine, works by blocking nerve cells from sending pain signals to your brain. It essentially shuts down the communication pathway between the tooth and your nervous system.
The numbness kicks in within a few minutes, though your dentist will usually wait a bit longer to make sure it’s fully effective before starting. You’ll feel pressure and vibration throughout the procedure, but not sharp pain. If the anesthetic includes epinephrine, a compound that constricts blood vessels and keeps the anesthetic concentrated in one area, your numbness will last 2 to 4 hours. Without it, the effect fades in 30 to 60 minutes.
Removing the Decay
Once you’re numb, the dentist uses a high-speed drill to cut through the enamel and reach the decayed portion of the tooth. The drill bit, called a bur, comes in different shapes depending on the cavity’s size and location. You’ll hear the familiar whirring sound and feel vibration, but this is the part where the anesthetic does its job.
After the drill opens up the cavity, the dentist switches to hand instruments to clean out the remaining decay more precisely. Spoon-shaped tools called excavators scoop out softened, damaged tooth material. Other instruments called hatchets shape and smooth the cavity walls so the filling material can bond properly. The goal is to remove every bit of compromised tooth structure while preserving as much healthy tooth as possible. Your dentist may periodically rinse and suction water from your mouth during this step.
Placing the Filling Material
With the cavity cleaned and shaped, the dentist fills the hole with one of two main materials: composite resin or amalgam. The choice affects how the rest of the procedure goes.
Composite resin is tooth-colored and can be matched to your existing teeth, making it virtually invisible. It bonds directly to the tooth surface and requires less drilling, which preserves more of your natural tooth structure. It’s the go-to option for front teeth and smaller cavities. The trade-off is durability: composites typically last 5 to 10 years.
Amalgam is the silver-colored filling material that’s been used for over a century. It’s exceptionally strong and lasts 10 to 15 years or longer, making it a common choice for molars that absorb heavy chewing forces. The downsides are cosmetic. Amalgam is visibly metallic, can discolor surrounding tooth structure over time, and often requires removing more healthy tooth to create a shape that holds the material in place.
Hardening With the Curing Light
If you’re getting a composite filling, your dentist will use a bright blue light that looks a bit like a small flashlight. This isn’t just for show. Composite resin starts as a soft, moldable paste, and the blue light (in the 400 to 500 nanometer wavelength range) triggers a chemical reaction that hardens it into a solid. Each layer of resin is cured for 10 to 40 seconds, depending on the depth. For deeper cavities, the dentist builds up the filling in multiple thin layers, curing each one before adding the next.
Amalgam fillings don’t need a curing light. They harden on their own through a chemical setting process, though they take longer to reach full strength.
Polishing and Bite Check
Once the filling is placed and hardened, the dentist smooths and polishes the surface to remove rough edges. This isn’t just cosmetic. A rough filling can irritate your tongue and trap bacteria. The dentist then asks you to bite down on a thin piece of colored paper called articulating paper, which marks the high spots where your upper and lower teeth make contact. Even a microscopic elevation in the filling can cause problems over time, creating cumulative trauma with every bite that leads to progressively worsening discomfort. If the bite feels off, the dentist shaves down the high spots until your teeth close together naturally.
What Recovery Feels Like
The filling itself is done, but you’ll leave the office with a numb face. Depending on the anesthetic used, this lasts anywhere from 1 to 5 hours. Articaine, one of the more common options, can keep you numb for 3 to 5 hours. During this time, avoid eating hard or hot foods. You can’t feel temperature properly, so a sip of hot coffee that would normally make you pull back won’t trigger your protective reflex, and you can burn your mouth without realizing it. Stick to soft, cool foods like yogurt, applesauce, or lukewarm mashed potatoes until the numbness wears off completely.
Some tooth sensitivity after a filling is normal, particularly to hot, cold, or pressure. Post-filling discomfort typically lasts 1 to 2 weeks, with noticeable improvement starting within the first 48 hours. Shallow to moderate fillings generally heal completely within two weeks. Deep fillings placed close to the nerve chamber can take 3 to 4 weeks for sensitivity to fully resolve. If your main complaint is pain when chewing that gets worse rather than better, the filling may be sitting too high and needs a quick bite adjustment.
When a Filling Isn’t Enough
Fillings work for minor to moderate cavities, but there’s a point where the damage is too extensive. If a cavity has gone untreated for a long time and destroyed a large portion of the tooth, a crown (a cap that covers the entire visible tooth) is a better option. The same applies if a tooth already has several fillings, because each time a filling is placed, natural tooth structure is removed. Stacking another filling on top of previous ones can weaken the tooth to the point where it cracks or breaks.
If decay has reached the nerve inside the tooth, a filling alone won’t solve the problem. That scenario requires a root canal to remove the damaged nerve tissue, followed by a crown to restore the tooth’s strength and function. Cracks in a tooth also call for a crown rather than a filling, since the crown holds the tooth together and protects the nerve from further exposure.