Cavities & tooth decay

Tooth decay, also known by its technical term, dental caries, is a process by which bacteria in the mouth create a sticky film, called plaque, that builds up and spreads on your teeth surfaces over time. When you consume foods or beverages containing sugar or other carbohydrates, certain types of plaque bacteria constantly feed on these particles, producing acid as a byproduct.

Plaque is inherently sticky, so the acid produced is held in close contact to the surface of your teeth. Over time, this acid eats away at the minerals (including calcium and phosphate) that form your tooth enamel in a process called demineralization. If plaque is not removed, your enamel is gradually eroded, and becomes porous – this is the early tooth decay process.

Now, the plaque acids can seep through the porous enamel into the softer underlying tooth material, known as dentin. When enough dentin is destroyed that the tooth’s enamel is undermined, it breaks down, creating a hole on the tooth’s surface known as a cavity. 1,2 Tooth decay can spread rapidly if left untreated, yet it’s not always easy to detect on your own since, in the early stages, it typically does not cause any discomfort.

Tooth decay is a common oral health problem and affects all age groups, from the time the first baby tooth pops into the mouth through all stages of life (including children, teens, and adults of all ages). While tooth decay can be found on any tooth surface, it’s most frequently seen in places where bacteria can sit undisturbed for longer periods of time: In the gaps between teeth, for instance, or in the pits and grooves of chewing surfaces. Tooth decay is also common in areas surrounding orthodontic brackets or around any defects where fillings or crowns meet the tooth.

The best way to prevent tooth decay and avoid cavities is to cut off plaque bacteria’s food supply. Limiting your consumption of sugary beverages, snacks, and refined carbohydrates (such as candy, cereal, cracks, cookies, sodas, and fruit juices) is an excellent way to limit bacteria growth. In addition, it’s particularly important to remove as much plaque as possible each day by practicing good oral hygiene. This includes brushing with a fluoride toothpaste for at least two minutes twice per day and flossing daily. If you are at higher risk of decay, your dentist may also recommend adding an over-the-counter fluoride rinse to your daily routine.

Finally, make sure to visit your dentist regularly for check-ups and professional cleanings. Your dentist can work with you to address any existing cavities or decay, determine your risk factors for developing future decay and come up with a long-term prevention plan. Follow these simple steps, and you’ll be able to enjoy a clean, healthy smile for a lifetime. 


Ready to learn more? Keep reading to find out the answers to some of the most frequently asked questions about Dental Caries, a.k.a. tooth decay and dental cavities. 

Tooth decay occurs when the acid secreted by plaque bacteria remains on tooth surfaces for too long. The decay process is typically slow and will usually take many months or even years to develop into a cavity. The rate of decay depends on a number of factors; some individuals may be genetically more prone to tooth decay than others. However, decay is commonly caused by the following:

  • Frequent consumption of sugar is the most important risk factor. This includes sugar, starches, refined carbohydrate-containing foods such as candy, chips, crackers, cookies, and high-sugar beverages such as soda and fruit juice
  • Inadequate oral hygiene habits (brushing, flossing, etc.).
  • Lack of fluoride use - fluoride is found in most toothpastes, and other professional and over-the-counter products such as rinses, gels and varnishes. In addition, a majority of city water supplies are optimized with a protective level of fluoride.
  • Orthodontic brackets and bands, leading to increased difficulty in reaching all tooth surfaces when brushing and flossing.
  • ·Existing fillings and crowns, which may create roughness or small gaps at the tooth’s surface, increasing prevalence of plaque.
  • Crooked or misaligned teeth.
  • Lack of adequate saliva flow (dry mouth), which can be related to smoking, Sjogren’s    syndrome and other diseases or medical conditions, and certain medications.
  • Eating disorders such as bulimia and anorexia.

In the most simplified sense, tooth decay can be understood as the process and a cavity as its end result. If the tooth decay process is caught early on, reversal is still possible – in this case, a cavity may never appear. In other words, an individual may be diagnosed with tooth decay without necessarily having had a cavity or ever needing a filling. Dental Caries is the technical term used to describe tooth decay and it refers to both the process and the end result, i.e. the caries process results in one or more carious teeth. 

The prevalence of tooth decay in the United States has declined dramatically over the past 50 years with greater use of fluoride (primarily toothpaste and community water fluoridation), wider education around oral health and improved access to dental care. Even though it is largely preventable, tooth decay remains a significant nationwide health problem for both children and adults, and particularly among some population groups.  

Tooth decay is the most common chronic disease among children aged 6-19.1 This is why it is so important that parents instill good oral hygiene habits from a young age and ensure that children receive regular dental check-ups and cleanings.

The percentage of children who have or have had tooth decay increases with age, affecting 21 percent of children ages 2-5, 50 percent of children ages 6-11, and almost 54 percent of those aged 12-19.2 About 13 percent of children ages 2-19 have untreated tooth decay.

Adults are by no means exempt, however. The 2011-2012 National Health and Nutrition Examination Survey found that 91 percent adults aged 20-64 had current or past dental decay, while 27 percent had untreated tooth decay. The survey also found that approximately 20 percent of adults aged 65 or older had untreated decay.3

An untreated cavity can worsen quickly, in some cases leading to an infection of the tooth pulp. This infection can lead to pulp death and tooth abscess or pulpitis. An abscessed pulp requires root canal therapy in order to save the tooth; in some cases, it may even require extraction (removal of the whole tooth). This is typically the case if the decay has destroyed a significant portion of the tooth’s structure.  

Left untreated for long enough, a tooth abscess can eventually spread into the tissues of the face and elsewhere in the body, which may be life threatening. Furthermore, an untreated cavity will irritate the gums, which may ultimately lead to gingivitis or periodontitis (gum disease).

If you think you may have a cavity or tooth abscess, or if you are experiencing any unusual oral pain, contact your dentist right away to schedule an appointment. Your dentist will be able to diagnose the problem and rule out other possible conditions besides an abscess or cavity.  

Fillings and crowns don’t “cure” tooth decay: They fill spaces in the teeth, or cavities, caused by plaque and erosion. Dental fillings and crowns can last a long time, but even the best filling or crown is not as resistant to new decay as a healthy, unrestored tooth. It’s important to note that fillings wear out and that they, too, can contribute to a buildup of plaque where the filling and tooth surface meet.

As years go by, you may need larger fillings or crowns to address additional decay that may occur in these areas. Of course, future problems can be prevented by practicing excellent oral hygiene, brushing for at least two minutes, twice per day, and flossing daily. Take extra care to clean hard-to-reach areas of your mouth and around any fillings, orthodontic brackets, or crowns.

See your dentist regularly to make sure you’re on track – keeping your appointments is the best way to prevent tooth decay or catch it early, when it’s still reversable. Do this, and you’ll likely avoid any unpleasant drilling and filling in the future. The best and most healthy teeth are the ones that never need a filling. 

Additional resources

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1Featherstone JDB. Community Dent Oral Epidemiol. 1999; 27:31-40. 

2Featherstone JDB. The continuum of dental caries – Evidence for a dynamic disease process. J Dent Res 83: (Spec Iss C) C39-C42, 2004.

3CDC. “Hygiene-Related Diseases.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 22 Sept. 2016,

4Fleming E, and Afful J. Prevalence of Total and Untreated Dental Caries Among Youth: United States, 2015–2016. NCHS Data Brief. No. 307. April 2018.

5Dye BA, Thornton-Evans G, Li X, Iafolla TJ. Dental Caries and Tooth Loss in Adults in the United States, 2011–2012. NCHS Data Brief. No. 197. May 2015