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Updated on August 15, 2022

Cavities: Symptoms, Causes & Cavity Fillings

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What Are Cavity Fillings?

Cavity fillings, also called dental fillings or tooth fillings, are most commonly used to fill minor cavities (decaying teeth).

Before a cavity filling is placed, your dentist administers a local anesthetic (numbing medication). Then a portion of your tooth is removed. Lastly, your dentist fills the cavity with a tooth-colored filling material.

Tooth fillings have a few purposes, including:

  • Closing spaces in teeth where bacteria, sugars, and food can enter, which prevents the progression of tooth decay
  • Repairing broken, chipped, or worn-down teeth
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Types of Cavities

Dental caries, also called carious lesions, is the process that results in tooth decay. Incipient lesions are considered “microcavities.” These lesions are limited to enamel only, so they can be "stopped" without a cavity filling.

However, larger cavities must be restored with a filling.

The lesions create chalky white spots on the surfaces of teeth. These white spots turn dark brown or black over time, which is the earliest sign of cavity formation.

There are six different types of cavities, including:

Class I

Class I cavities form in the pits and fissures of teeth, which is why they are called “pit-and-fissure lesions.” They typically develop in the biting surfaces of posterior (back) teeth. They also form in the grooves of top and bottom molars.

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Class II

Class II cavities develop in between back teeth, including premolars and molars.

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Class III

Class III cavities develop in between anterior (front) teeth. Front teeth include your incisors and canines. However, these cavities do not form on the biting edges of your front teeth.

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Class V

Class V cavities form on the gum line of both front and back teeth. Plaque buildup on the gums is common, which may result in white spots on teeth.

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Class VI

Class VI cavities form on the cusp tips of premolars, molars, and the biting edges of incisors and canines (front teeth).

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If cavities are left untreated, tooth loss can occur.

Symptoms of Cavities

Small cavities usually do not cause any symptoms. Yearly x-rays are necessary to catch them early. If a small cavity isn’t filled in time, it will get larger and symptoms typically begin to develop.

However, by the time cavity symptoms are noticeable by the patient, the cavity is past the point of being restored with just a filling.

Common symptoms of large cavities include:

  • Toothache — recurring tooth pain or pain that occurs without any cause.
  • Tooth Sensitivity — sharp pain in the tooth caused by thermal stimulation, such as cold, hot, or sweet substances.
  • Tooth Holes — once a cavity has developed, holes typically appear on the tooth.
  • Dark Stains — white spots caused by carious lesions develop into brownish or black spots over time.
  • X-rays — sometimes cavities aren’t noticeable on the surface. If tooth pain or sensitivity is present, a dentist will take an x-ray to check for decay. Dentists also check for cavities during routine check-ups and teeth cleanings every six months.

What Causes Cavities?

Plaque forms due to the long-term buildup of food particles, bacteria, acid, sugars, and saliva.

Plaque is highly acidic. It attacks your tooth enamel, resulting in holes and dark spots on your teeth.

cavity NewMouth

If plaque is not removed, it can turn into hardened dental plaque (tartar), which is difficult to remove. The earlier a cavity is caught, the easier it is to treat.

Other common causes of cavities include:

Dietary Habits

The leading cause of cavities is from foods and drinks high in sugar, including fruit juices and candy. White starches, such as pasta, bread, chips, and crackers can also cause cavities over time. Mouth bacteria feed off of simple sugars, eventually turning into plaque.


Smoking itself doesn't cause cavities. Tobacco's main role in cavity formation is that it causes dry mouth, which can lead to cavities. Over time, smoking can also create dark stains on the teeth.

If you smoke, it is essential to avoid acidic foods and drinks that can worsen teeth stains, such as coffee, soda, and tea. The combination of sugary foods (mentioned above), acidic liquids, and dry mouth can lead to tooth decay.

Medications and Dry Mouth

Dry mouth occurs when the salivary glands in the mouth do not make enough saliva to keep the mouth wet. Dry mouth is commonly caused by some medications. Over time, cavities can form.

Medications that can cause dry mouth include:

  • Antihistamines
  • Antidepressants
  • Sedatives
  • Pain medications
  • Parkinson’s disease medications
  • High blood pressure medications
  • Antacids
  • Decongestants

Poor Oral Hygiene Practices

Good oral hygiene is essential for cavity prevention. This includes brushing twice a day, flossing every day, and rinsing with mouthwash regularly. Fluoride toothpaste also helps prevent tooth decay.

Visiting the dentist every six months for teeth cleanings and yearly x-rays is also essential. This allows your dentist to catch cavities early, prevent further decay with treatment, and check for signs of gum disease.

Types of Direct Cavity Fillings

There are three main types of direct cavity fillings available. Direct fillings are made inside of the mouth during one office visit. Different types of fillings include:

Composite Fillings

Composite material is a tooth-colored acrylic resin. It is the most common restorative material used for cavity fillings, broken teeth, and chipped teeth.

Composite fillings are used to restore cavities in posterior teeth (premolars and molars).

composite cavity filling NewMouth
  • Advantages — The main advantage of composite fillings is that they are tooth-colored and blend in with your natural teeth. Composite resin material is strong, durable, and blends in with your natural tooth color.
  • Disadvantages — Even though composite fillings are strong and durable, they are more susceptible to cavities than amalgam fillings. Composite fillings last up to five years, while silver amalgam fillings can last 10 to 15 years.

Silver Amalgam Fillings

Silver amalgam fillings are a mixture of mercury with silver, tin, and copper. Mercury in dental amalgam is also non-toxic, strong, and stable.

Silver fillings are usually used to restore posterior baby teeth (premolars and molars).

amalgam filling NewMouth
  • Advantages — Amalgam fillings last 5 to 10 years longer than composite fillings. This is because they are the strongest and most durable direct fillings on the market today. Amalgam restorations are also the cheapest cavity filling available.
  • Disadvantages — Despite the many advantages of amalgam fillings, they are not as aesthetically pleasing as composite fillings. However, these fillings are not visible if they are used to fix back molars.

Glass Ionomer Fillings

There are two types of glass ionomer fillings:

Conventional Glass Ionomer (CGIs)

These fillings are another tooth-colored restoration made of polymerizable acids and ion-leachable glass particles. CGIs also release fluoride, which helps prevent future cavities.

Glass ionomer is not as durable as amalgam or composite.

Resin-Modified Glass Ionomer (RMGI’s)

These fillings are similar to CGIs, but with more strength and added acrylic resins. RMGI’s are typically used to fill cavities in primary teeth (baby teeth).

They are tooth-colored but not as versatile and aesthetic as composite resin fillings.

Types of Indirect Cavity Fillings

Indirect cavity fillings are made outside of the mouth, typically in a dental laboratory. They are custom-made for every patient depending on their needs, tooth structure, and severity of tooth decay.

Common types of indirect fillings include dental inlays and onlays.

Indirect fillings restore cavities that are too large for a simple cavity filling. They also take two office visits to complete.

Types of indirect fillings include:

Porcelain cavity fillings

These fillings are tooth-colored restorations that copy the function and color of natural teeth. The color of porcelain and natural teeth are almost identical.

These fillings are also strong and less likely to fracture than composite fillings. They are ideal for patients who want a long-lasting restoration with aesthetics at the forefront.

Gold cavity fillings

Gold fillings are the strongest indirect cavity fillings available. They protect weakened teeth cusps caused by trauma, decay, or deep cavities.

Unlike composite and porcelain fillings, gold fillings are not aesthetically pleasing. However, they are stronger and less prone to damage over time.

Which Dental Specialists Fill Cavities?

General dentists, family dentists, and pediatric dentists are the main providers of dental fillings for children and adults.

They also specialize in other dental treatments, including teeth cleanings, restorations, and sealants.

Treatment Cost & Insurance

The cost of a cavity filling depends on the type of filling and the dentist’s location. Since fillings are used to treat cavities or trauma-related dental conditions, part or most of the procedure is covered by dental insurance.

The prices below reflect the cost of a cavity filling procedure without insurance:

Silver Amalgam Filling $50-$200 (per tooth)
Composite Filling $90-$300 (per tooth)
Glass Ionomers $90-$300 (per tooth)
Indirect Gold or Porcelain Filling $500-$4,500 (per tooth)
4 Sources Cited
Last updated on August 15, 2022
All NewMouth content is medically reviewed and fact-checked by a licensed dentist or orthodontist to ensure the information is factual, current, and relevant.

We have strict sourcing guidelines and only cite from current scientific research, such as scholarly articles, dentistry textbooks, government agencies, and medical journals. This also includes information provided by the American Dental Association (ADA), the American Association of Orthodontics (AAO), and the American Academy of Pediatrics (AAP).
  1. Lygre, David G. General, Organic, and Biological Chemistry. John Wiley, 2003.
  2. Hollins, Carole. Basic Guide to Dental Procedures. John Wiley & Sons, Inc., 2015.
  3. Syrbu, John DDS. The Complete Pre-Dental Guide to Modern Dentistry. 2013.
  4. American Dental Association (ADA), Tackling tooth decay. 2013.
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