How Many Cavities Should You Have by 30? The Real Answer

April 20,2026

Most people hit 30 and start wondering how they stack up. The gym routine. The retirement savings. And yes, even the teeth.

If you've ever sat in a dental chair and thought, "Wait, how many fillings do I actually have?" you're not alone. It's one of those questions people Google quietly but rarely ask out loud.

So here is the real answer, backed by the latest government data from both the US and Canada.

The short version: the clinical ideal is zero untreated cavities. Statistical reality? By your early 30s, most North American adults have 6 to 10 teeth that have been affected by decay in some form, mostly restored through fillings. That gap between "ideal" and "average" is exactly what's worth understanding.

If you're already feeling uncertain about where your own dental health stands, speaking with a dentist in North Vancouver is a good first step toward getting a clear picture.

What the Data Actually Shows for Adults Around Age 30

These numbers come from two of the most credible sources available: the US Centers for Disease Control and Prevention (CDC) and Statistics Canada.

US data (CDC 2024 Oral Health Surveillance Report, NHANES 2017 to March 2020, published October 2024):

Among adults aged 20 to 34 who have any history of tooth decay, the average DMFT score is 6.4 teeth affected. DMFT stands for Decayed, Missing, and Filled Teeth. Here is how that breaks down:

Untreated decayed teeth: 0.8
Teeth missing due to decay: 0.7
Teeth that have been filled: 4.8

So on average, a 30-something in the US has nearly 5 filled teeth from past cavities, less than 1 tooth with active untreated decay, and less than 1 tooth lost to disease.

Canadian data (Statistics Canada, Canadian Health Measures Survey, 2022 to 2024):

93% of Canadian adults aged 20 to 79 have at least one permanent tooth affected by decay. That's down slightly from 96% in 2007 to 2009, but the change is modest.
The average DMFT score for Canadian adults sits at roughly 9.2 to 9.7 affected teeth nationally.
Advanced untreated decay affects 22% of adults.

What does this mean for you?

Having a handful of fillings by 30 is statistically common. What's not acceptable from a health standpoint is leaving decay untreated. That's what causes pain, infection, and eventually tooth loss.

The Number That Actually Matters: Untreated Decay

Fillings from years ago are not the concern. The real issue is decay that is sitting in your mouth right now without treatment.

Here is where things get important:

21.8% of US adults aged 20 to 34 currently have at least one untreated cavity (CDC 2024).
In Canada, the average adult has approximately 2.9 untreated coronal cavities (Statistics Canada, CHMS 2022 to 2024).
Untreated decay rates in Canada have not declined meaningfully in over 15 years, according to the same Statistics Canada data.

The CDC's 2024 report notes directly: "Levels of untreated cavities are higher for some groups because of factors such as race and ethnicity, income level, and smoking status."

In the US, untreated decay is notably more common among:

Males (22.8%)
Non-Hispanic Black adults (30.3%)
Adults in high-poverty situations (39.6%)
Current smokers (41.4%)

These aren't just statistics. They reflect real barriers to care, including access, cost, and systemic gaps in preventive health systems.

The bottom line: If you have a few old fillings, that's history. If you have decay that hasn't been treated, that's what needs attention now.

Is It Normal to Have Cavities at 30?

Yes, statistically speaking, it is common. But "common" and "normal" are not the same thing in dentistry.

Here is a quick breakdown based on the data:

Situation	What It Means
Zero cavities ever	Uncommon but achievable, especially with early preventive care.
1 to 5 filled teeth, no active decay	Within or below average; good ongoing prevention matters.
6 to 10 filled or affected teeth	Near or at the North American statistical average.
Any currently untreated decay	Needs professional attention regardless of total count.
Rapid new cavities in your 30s	Worth investigating causes with your dentist.

The goal at any age is not to meet the "average." The goal is zero active, untreated decay and a plan to prevent new ones.

Why Some People Reach 30 With No Cavities

It's not just luck, though genetics do play a role. Research published in the Journal of Dental Research found that genetic factors account for a meaningful portion of caries susceptibility. Daily habits are just as important.

People who tend to reach their 30s with minimal or no cavities often share a few common patterns:

Consistent daily flossing and brushing, which disrupts the bacterial biofilm (plaque) that causes decay
Low intake of added sugars and acidic beverages, which reduces the acid attacks on enamel
Regular professional cleanings and checkups, which catch early-stage decay before it becomes a filling
Fluoride use, whether through toothpaste, water, or professional treatments, which strengthens enamel over time
Early dental care in childhood, which sets the foundation for adult oral health

According to the World Health Organization's March 2025 fact sheet, untreated dental caries in permanent teeth remains the most common health condition worldwide. It is widespread, but it is also largely preventable.

At be well dental, we see this play out regularly. Patients who come in consistently and catch small issues early tend to need far less work over time.

Why Cavities Can Still Show Up After 30

Here is something many people don't expect: your cavity risk doesn't go down just because you're no longer a teenager eating Halloween candy.

Several factors can drive new decay in adulthood:

Dry mouth is one of the more underappreciated ones. Many common medications, including antihistamines, antidepressants, and blood pressure drugs, reduce saliva flow. Saliva is your mouth's natural defence against acid. Less saliva means more risk.

Gum recession exposes the root surfaces of teeth, which don't have the same enamel protection that the crown of a tooth does. Root cavities are more common in adults over 30.

Diet changes that sneak in over time, like more coffee with sugar, energy drinks, or snacking patterns, create more frequent acid exposure throughout the day.

Skipped checkups during busy life stages (new jobs, young kids, moving) allow small issues to quietly grow into bigger ones.

The CDC data supports this: filled teeth increase steadily with age, from an average of 4.8 at ages 20 to 34 to 7.5 at ages 50 to 64. Life keeps adding to the total unless active prevention is maintained.

What Is a DMFT Score and Why Should You Know Yours?

DMFT stands for Decayed, Missing, and Filled Teeth. It's the standard measurement used by dentists and health researchers worldwide to track cavity history.

D = Teeth that currently have untreated decay
M = Teeth lost because of decay
F = Teeth that have been filled or restored

A DMFT score of 0 means no history of decay in permanent teeth. A score of 6 means six teeth have been affected in some way, whether treated or not.

For context: the US average for adults aged 20 to 34 is 6.4. The Canadian national average for all adults is approximately 9.7. These are population averages, not targets.

Your own dentist can walk you through what your personal history looks like and, more importantly, what your current risk factors are going forward.

If you're not sure when you last had a full dental exam with X-rays, that's worth addressing. A dental checkup in North Vancouver gives you a clear baseline, both for your DMFT history and for any issues that need attention now.

Practical Steps to Keep Your Numbers Low From Here

Whether you currently have no fillings or several, the approach from this point forward is the same.

Daily habits that protect your teeth:

Brush twice a day with fluoride toothpaste for two full minutes
Floss once a day (even if you don't love it)
Limit sugary or acidic drinks, especially between meals
Drink water throughout the day to support saliva flow

Professional care that makes a difference:

Cleanings and checkups every six months, or more frequently if you have higher risk factors
X-rays at regular intervals to catch decay between teeth and below the gumline
Ask about fluoride treatments or dental sealants if you're prone to new cavities
Mention any medications you're taking, especially if dry mouth has become an issue

At be well dental, we use 3D imaging and digital technology so you can actually see what's happening in your mouth. Understanding what's going on is the first step to making good decisions about it.

Ready to Know Where You Actually Stand?

If you haven't had a dental exam in a while, or if you've been wondering whether your cavity count is something to be concerned about, the most useful thing you can do is get a professional look.

The numbers in this article give you a benchmark. But your mouth is specific to you, and only a proper exam with current X-rays can tell you what's actually happening right now.

The team at be well dental in North Vancouver welcomes new patients and families from North Vancouver, West Vancouver, Burnaby, and Vancouver. Led by William Yeung, DMD, our clinic brings over 100 years of combined experience and offers everything from preventive care and general dentistry to cosmetic procedures, implants, Invisalign, and more, all under one roof.

Book your checkup and come as you are. There's coffee in the reception area and no judgment in the chair.

Frequently Asked Questions

How many cavities is normal by age 30?

The clinical ideal is zero untreated cavities. In terms of what's statistically average, adults aged 20 to 34 in the US have a DMFT score of approximately 6.4, meaning around six affected teeth, mostly restored through fillings. Canadian data shows a national adult average closer to 9.7. Having some fillings is common, but any currently untreated decay warrants attention.

Is it bad to have 5 or more cavities at 30?

Having several filled teeth by 30 is within or near the statistical average for North America. The more important question is whether any of those cavities are currently untreated. Active, ongoing decay that hasn't been addressed needs professional care before it progresses further.

Why do I keep getting cavities even though I brush?

Brushing is important, but it's not the only factor. Diet, flossing habits, fluoride use, dry mouth (often medication-related), and how frequently you see a dentist all play a role. Some people also have higher natural susceptibility based on the composition of their saliva or the structure of their teeth. A dentist can help identify what's driving new cavities in your specific case.

Can you stop getting cavities after 30?

Yes, it's entirely possible to go years without a new cavity with the right preventive routine and regular professional care. But the risk doesn't disappear on its own. It requires consistent daily habits and regular monitoring by a dental professional.

What is a good DMFT score for a 30-year-old?

Zero is the ideal. In practice, a DMFT score of 0 to 4 at age 30 is below the national averages for both the US and Canada and reflects good preventive outcomes. A DMFT above 6 is closer to or above the current average and warrants a closer look at current risk factors and whether any decay remains untreated.

How often should adults in their 30s see a dentist?

Most dental organizations recommend a checkup and professional cleaning every six months. Some patients with higher cavity risk may benefit from more frequent visits. If you're not sure what's right for your situation, a general exam is the best starting point.

Does North Vancouver have higher cavity rates than other Canadian cities?

City-level cavity data specific to North Vancouver is not published separately from national Statistics Canada figures. For a clear picture of your own dental health and any relevant local trends, speaking directly with a dental professional in your area gives you the most accurate guidance.