How Cavity Fillings Work

what are cavity fillings

Learn how cavity fillings work and why they are beneficial.

When you have a cavity, you know it’s time to get a filling. However, you may not know how fillings work and what the dentist is doing when operating on your teeth. Understanding what happens during a cavity filling is useful for not just calming your nerves around the procedure but for understanding why fillings are important to have. Read on to understand how cavity fillings work and why you should not hesitate to get one when it’s needed. 

What Cavity Fillings Do

A cavity describes the hole left behind after tooth decay destroys part of your tooth. The cavity in the tooth still contains the bacteria that created it, and if left unchecked, the decay will continue to spread throughout the tooth. 

During cavity filling procedures, dentists usually clean away the decay with a drill before filling it in. Removing the decay prevents further damage but does not fix the damage that has already occurred, which is why a filling is necessary

Fillings are often made from composite resin, but some dentists still use silver amalgam and glass ionomer fillings. These fillings replace the part of the tooth destroyed by decay, and your dentist molds them to match the shape of your surrounding tooth. Cavity fillings help restore full health and functionality to a tooth, with composite fillings match your tooth’s color for an even look. 

How Dentists Insert Cavity Fillings

First, dentists numb the tooth that is going to be treated with a local anesthetic. This also numbers the surrounding gums and jaw, and once the area is entirely numb, the dentist uses their drill to remove the decay. Then, the specific method used to insert the filling depends on what type of cavity filling they use. 

Composite Resin

This filling matches your tooth’s color and can last up to 15 years with good oral hygiene. When the dentist inserts the composite, it is in paste form and molds to the cavity’s shape. Once it is properly placed, the filling is hit with a bright ultraviolet light to harden it quickly. 


These fillings are a mix of silver, tin, and mercury. These fillings are less expensive, longer-lasting, and easier to place than composite resin fillings, but they look less natural. When placing it, the dentist tightly compacts the mixture into the cavity to ensure there are no air pockets. Then, they carve it into shape, match the contours of the tooth, and make sure the bite is proper. 

Why Cavity Fillings Are Important

When tooth decay destroys part of your tooth, the resulting cavity is very sensitive. It can expose inner nerves, compromise the tooth’s structural integrity, or invite continued infection. If the dentist only removed the decay from inside the cavity, the hole itself would be a problem for the tooth. By filling the hole, your dentist restores your tooth to its proper functionality. 

Fillings prevent bacteria or plaque from building up and reinforce the tooth’s strength. Cavity fillings are essential for restoring your tooth’s health and preventing further debilitating damage to your mouth. 

Keep Your Smile Healthy with Affinity

While these tips can help with some tooth and gum sensitivity issues, we know the best way of correcting the problem is to visit your dentist regularly. Affinity Dental, located in Catonsville, MD, has six dentists and provides a variety of services from pediatric dentistry to orthodontics. Affinity Dental is capable of meeting all your needs. With 170 combined years of treating a variety of dental needs, Affinity is committed to providing quality dental care. To get your teeth back into good health and make your smile bright, call us at 410-719-7900 or contact us online. For other useful tips on dental care follow us on Facebook and Twitter.

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