Dentistry for the Entire Family in Fridley MN
Call 763.586.9988 to schedule a dental appointment at Dentistry for the Entire Family in Fridley MN


What is tooth decay and why is it a problem?

Article updated 5/26/2023

Tooth decay: A preventable dental problem. Why does it still exist?

What is tooth decay?

Tooth decay may appear as a black spot on a toothTooth decay (also known as cavity or dental caries) is a disease process caused by a bacteria (Streptococcus mutans) that impacts the health and integrity of weakened tooth enamel–leaving a hole in the surface of a tooth.


Streptococcus mutans is one of hundreds of bacteria that are present in our mouth at any given time. Not all bacteria are good or bad.


Problems arise when (problematic bacteria S.mutans) are able to multiply at a faster rate than the good bacteria—resulting in an imbalance and the development of a hole or cavity in one or more surfaces of a tooth or teeth.


Tooth decay is a problem despite the fact that decay is easily preventable


According the Centers for Disease Control, the presence of dental caries is one of the most common chronic conditions in the US (Source).


The stats are troubling considering the fact that tooth decay can be easily prevented with an effective oral health care routine at home between professional teeth cleaning visits at your dentist.


There is no known cure for tooth decay contrary to what a Google search results may show you. You can be certain that if a tooth decay cure is found, it will headline your favorite news program, newspaper, and magazines.


Until that time, the best way to prevent tooth decay is prevention. Prevention includes brushing for two-minutes following meals with a fluoridated toothpaste, flossing daily, eating a diet low in sugar, and having your teeth professionally cleaned and examined by a your dentist every six months.

What are the possible reasons for tooth decay?

The reasons for why tooth decay develops are endless and are dependent upon an infinite number of variables. Listed below are the most common reasons for why a person may develop dental caries or may be at higher risk for developing a cavity.

  • Ineffective oral health care home practices including lack of brushing teeth and/or flossing teeth daily
  • Diet includes high consumption of foods high in sugar and/or includes candy
  • People who graze or snack frequently between meals
  • Consumption of more than twelve (12 oz) of carbonated, acidic beverages per day
  • People who have crowded or teeth that overlap making it difficult to effectively clean between and/or around
  • People who take dietary supplements, herbal remedies, over-the counter remedies, or prescription medication

After reading the above list, it’s safe to say that we’re all at risk for tooth decay—no one is immune from tooth decay.


We know now that a high number of S. mutans increases our risk to develop tooth decay and we know we’re all at risk for tooth decay, but how do dental caries form? How long does it take? And when and how will my dentist know if I have a cavity?


Before being able to understand how a cavity forms, it’s important to know and visualize the three primary layers of a tooth in order to understand the decay process.

Layers of a tooth

Human tooth anatomy of a molarIn order to understand how cavities form, it’s important to know a little bit of tooth anatomy. A human tooth has three primary layers: enamel, dentin, and a pulp.


Tooth enamel is the outermost white colored layer of a tooth and is visible when you look inside your mouth with a mirror.


Dentin layer is the middle layer of a tooth and contains nerve endings that are stimulated when exposed to extreme temperatures such as drinking something really cold, hot, or even sour or sugary.


Pulp is the innermost layer and contains the nerve and blood supply.





How do cavities form?

Dental caries develop as a result of a bacterial process that gradually breaks down the outermost layer of a tooth called enamel—leaving an exposed hole in the surface of the tooth.


A cavity will continue to grow until restored by your dentist.

Healthy tooth plus acid can cause a cavity

People at high risk for tooth decay often have a high number of Streptococcus mutans (bacteria) present in their mouth at any given time.


When we eat, the bacteria in our mouth mixes with our food, drink, sugars, and sweets from our diet to produce an acid.


Healthy tooth enamel + acid = high risk for tooth decay


Healthy tooth plus acid weakens tooth enamel, a process dentists call demineralization. Demineralized tooth surfaces are at high risk to develop tooth decay and are often noted in your clinical record as areas to watch.





tooth enamel demineralization increases when mouth ph is below 5.5Demineralization is a technical term used by your dentist to describe compromised or weak areas of tooth enamel exist. Demineralization of tooth enamel occurs when tooth enamel is exposed to acid levels with a ph of 5.5 or lower from foods and beverages.


What is pH?

Ph is a scale that measures on a scale of 1-14 (neutral is 7.0) for how acidic a substance is or isn’t. Substances that are not acidic (ph value is 7.0 or above) are referred to as basic.
Dental researchers have found that tooth enamel demineralizes and increases the likelihood that a cavity will form when exposed to substances with a ph of 5.5 or lower.

Shown right is a ph chart showing the ph values of popular soft drinks. Image Source:

Chart listing the ph of popular beverages
In 2016, The Journal of the American Dental Association published an article titled, The pH of beverages in the US. The article is a worthy read and contains several tables that list the pH of specific beverages.












How long does it take for a dental cavity to form?

How long it takes for a dental cavity to form depends on many factors including the frequency and duration of “acid attacks”.
Real-life example
Sip all day, get decay posterSay for example, you’re thirsty and wish to open and enjoy your favorite soft drink while you’re working at work. Once open, you take a sip–and proceed to continue working on your task at hand.
A few minutes later, you take another sip–and proceed to continue working on your task at hand. And you repeat this process over and over till your soft drink is empty. How long did it take you to consume your beverage?
More than 20 minutes?
Chances are that it took you more than 20 minutes to consume.
What is significant about 20 minutes?


Dental researchers have found on average that it takes the saliva in our mouth approximately 20 minutes to neutralize the pH in the mouth following an acid attack.


In a nutshell, what this means is that it takes the saliva in your mouth twenty minutes to neutralize following each of your sips (aka acid attack). If you’re like most people, chances are high that you took multiple sips within a 20 minute period. This results in a longer duration of an acid attack and an increased risk for developing tooth decay.


The Minnesota Dental Association has a popular public awareness campaign, “Sip all day, get decay” that helps inform the public that sipping all decay increases the likelihood that you’ll develop tooth decay.


Suffice to say that the answer to how long it takes for a cavity to form will vary person to person.
Duration and frequency are the two most important variables that impact how long it’ll take for tooth decay to develop from the enamel layer to the pulp.


Stages of tooth decay illustrationOther important variables for how long it takes for a cavity to form are: tooth anatomy, function, and integrity.

  • Tooth anatomy. Each tooth has three layers (enamel, dentin, and pulp). The thickness of each layer will vary by tooth. Back molar teeth have more enamel thickness than a front tooth.

  • Function. The more a tooth is used, the more vulnerable a tooth is to tooth decay. This analogy is similar to sports. A team player on the field will increase the chances of getting hurt more than a player on the sidelines watching.

  • Integrity. A tooth with a thick layer of enamel will weather an acid attack better than a tooth with a thin or demineralized enamel layer.


With an understanding of how tooth decay develops and factors that impact how long it takes a cavity to form, you’re likely wondering how will your dentist know if you have a cavity? Great question!


How will my dentist know if I have a dental cavity?

Your dentist will recommend to take a series of dental x-rays called bitewing x-rays.
Bitewing x-rays are also called decay detecting films because they enable your dentist to check for tooth decay between your teeth that are not visible during a visual clinical dental exam.

Bitewing x-rays enable dentist to check for cavities between teeth


How frequently are bitewing x-rays taken?
Your dentist will prescribe bitewings based upon your risk for tooth decay and past or current medical/dental history.


What does tooth decay feel like?

Many times a person may not feel tooth decay until the decay has progressed into the dentin layer of the tooth.
Once decay penetrates tooth dentin, a person may notice increased sensitivity while chewing as well as increased sensitivity to temperatures, sweet, sour, and/or acidic foods.
Left untreated, tooth decay will eventually progress into the pulp (innermost layer of the tooth) causing extreme pain.


What does tooth decay look like?

Tooth on watch for cavityTooth decay is often described as a visible black spot on a tooth. This description is misleading because tooth decay is a hole on the surface of a tooth.
The color inside the hole (cavity) of a tooth will vary. Teeth surfaces are porous and take on surface stains and discolorations from coffee, tea, smoking, and/or adjacent dental fillings.
Additionally, the hole will appear dark brown or black from shadows cast from adjacent cheek, tongue, lips, and from overhead lighting. This is why people and articles often describe tooth decay as a visible black or brown spot on a tooth. Photo source.
On a bitewing x ray, tooth decay will appear as a darker shade of gray. This person’s bitewing pictured right has a very large area of tooth decay (outlined in red) that is likely quite painful for the person. Photo source.


Cavity appears as a dark gray lesion on an x-ray












How to prevent cavities: Our top 10 tips

List of ten tips to help prevent cavities
Prevention is key to helping to prevent cavities.

  1. Brush daily for two-minutes following meals using a toothpaste containing fluoride.

  3. Floss between teeth daily.

  5. Eat a well-balanced diet low in sugar.

  7. Limit soft drinks to no more than 12 ounces per day.

  9. Have your teeth professionally cleaned and examined by your dentist every six months.

  11. Provide consent to enabling your dentist to take bitewing x rays as necessary.

  13. Provide consent for the application of fluoride varnish following your professional teeth cleaning. Fluoride varnish is an added layer of protection to help prevent tooth decay.

  15. Consider orthodontic therapy (dental braces) if you have crowded or teeth that overlap and make it difficult for you to effectively clean your teeth.

  17. Parents with children. Discuss the option to have dental sealants applied to the chewing surfaces of permanent molars of your children’s teeth.

  19. People who take prescription medications and/or experience a dry mouth can now use a prescription strength fluoride daily at home, between dental visits to help reduce the risk of tooth decay.



Tooth decay FAQ

Listed below are answers to some of the most frequently asked questions asked by patients regarding tooth decay. If you have a question that is not answered, email us and we’ll respond promptly.


How does one stop and reverse the process of tooth decay?

There is no known cure for tooth decayFact. There is no cure for tooth decay. Many patients will tell us that they’ve tried various means to “reverse or cure their tooth decay naturally” using a method or product they found on the internet.
Fact. The only cure for tooth decay is having your tooth examined and restored by your dentist.
Fact. The best way to stop and or reverse the process of tooth decay is to be proactive to help prevent tooth decay from developing. See our top ten recommendations above.



Does everyone eventually get cavities?

No. Not everyone will develop tooth decay. There are alot of variables for who and why people develop tooth decay. Generally speaking, tooth decay is preventable.


Why are some people immune to dental caries?

No one is “immune” to dental caries. Some people have a lower risk for tooth decay. Tooth anatomy, personal, and dietary habits and practices impact how likely a person is to develop tooth decay. For the record, dentists are not immune to tooth decay.


Can tooth decay be passed from person to person?

Tooth decay can be transmitted person to personThe answer is yes. Several studies have shown that Streptococcus mutans (tooth decay bacteria) can be transmitted to others via shared food, utensils, kissing, and even during sneezing.
Additionally, there have been numerous peer-reviewed studies that have shown “Mothers with cavities can transmit caries-producing oral bacteria to their babies when they clean pacifiers by sticking them in their own mouths or by sharing spoons.” (Source: Science News)


Do cavities cause bad breath?

Bad breath or halitosis can be a sign–but not a definitive sign that you or a loved one may have tooth decay. There are number of reasons for why people could or have “bad breath”.


How to rebuild the enamel on my teeth?

Unfortunately there is no means to rebuild lost enamel on your teeth; however, you can take proactive measures to strengthen weak areas of enamel. See our top ten tips listed above for how to prevent tooth decay and make a note to talk to your dentist at your next visit.


How do medications increase tooth decay?

Dry mouth from medications can increase tooth decay riskXerostomia, also known as dry-mouth, is a common side effect for many prescription medications. 
A decreased amount of saliva in the mouth increases a person’s risk for tooth decay as well can cause difficulties in chewing, swallowing, tasting, and speaking.


According to the American Dental Association, 30% of tooth decay in older adults is attributed to dry mouth.


It is important that you provide your dental provider with a current list of prescribed medications as well as any over-the counter, herbal, vitamin/mineral, dietary supplements you are taking at every dental visit so they can help you to reduce your risk for tooth decay.
If you suffer from dry mouth, your dentist may prescribe a prescription strength brush on fluoride to help reduce your risk for tooth decay.


How do dental sealants prevent cavities?

First and second permanent molars have prominent and deep grooves and pits on the the chewing surface of the tooth that are difficult to access and clean using a toothbrush.
For this reason, your dentist will recommend dental sealants as a preventive measure to help prevent tooth decay from developing. A dental sealant fills the deep pits and grooves making it easy to effectively clean the chewing surfaces of molars with a toothbrush.
The application of sealants requires no anesthetic, no drilling, and can be easily applied in just a few minutes. Photo source: Pinterest


Are dental sealants just for kids, or can adults get them?

Image of before and after placement of a dental sealantDental sealants help prevent tooth decay on cavity-free, permanent molars. Dental sealants are applied to the chewing surfaces of permanent molars as soon as they are fully erupted.
An adult has 32 teeth, twelve of which are molars (first, second, and third molars). On average, first molars erupt around six years of age. Second emerge molars around twelve years old, and third molars—teen years or later.
Because research has repeatedly shown that the first 24 months for a newly erupted tooth is the most vulnerable time period for tooth decay to develop, is why dental sealants are predominantly recommended for kids. So long as an permanent molar is cavity-free, a dental sealant can be applied.



Does dental insurance cover dental sealants?
Many dental insurance plans do provide coverage for the application of dental sealants. Coverage varies so it is recommended that you review your benefits or ask your dentist to help verify coverage for you.


Is diet pop better to drink?

Limit soft drink intake to less than one can dailyDiet soft drinks are marginally better at best than their full-sugared counterparts. Both varieties cause the pH in the mouth to plunge to levels that demineralize and weaken tooth enamel. Click on hyperlink to an article that includes numerous charts and tables about the pH of your favorite beverages.



Can you get cavities from smoking?

No, but smokers are at higher risk for developing tooth decay as a result of increased amount of tooth stain which harbors harmful bacterial plaque.
Additionally smokers are at higher risk for developing periodontal disease, an irreversible condition that results in the loss of bone that holds teeth inside the jawbone.
Smokeless tobacco is not a better alternative. The pH of smokeless tobacco is acidic—varies by manufacturer and product, and has a known reputation for causing gums to recede.
Receding gums means that the tooth layer known as dentin is exposed. Exposed dentin is at high risk for developing tooth decay as well as increasing tooth sensitivity.



If you suspect that you or a loved one may have a cavity, it’s best to call for an dental exam appointment.

Call Dentistry for the Entire Family at (763)586-9988 or request an appointment via email. Dentistry for the Entire Family welcomes new patients and is in network with most dental insurance providers.


Sorry, comments are closed for this post.


Dentistry For the Entire Family

1099 East Moore Lake Drive

Fridley, MN 55432

Phone (763) 586-9988

Fax (763) 586-9977

Email Us

Hours of Operation

Monday 7:30am - 5:00pm

Tuesday 7:30am - 5:00pm

Wednesday 7:30am - 6:00pm

Thursday 7:30am - 5:00pm

Friday 7:30am - 3:00pm

Saturday Closed

Sunday Closed