Why do I still get cavities if I brush and floss every day?

You have cavities despite brushing flossing every day. That feels unfair, especially when you are already doing the basics and still hearing you need another filling.

Brushing and flossing still matter. They break up the plaque biofilm, but they do not cancel out dry mouth, acid, frequent sugar exposure, deep grooves, or spots you keep missing.

A few causes explain most cavities with good oral hygiene

If you are still getting decay, the usual suspects are pretty plain. Dry mouth, medicines that reduce saliva, acid from soda or reflux, all-day snacking or sipping, deep molar grooves, and brushing at the wrong time or missing the gumline and between-teeth areas.

Use the pattern, not guilt, to narrow it down. The cause usually shows itself by when the problem is worst, which teeth keep getting cavities, and what makes your mouth feel better or worse.

• Dry mouth or meds: your mouth feels sticky, especially at night or when you wake up.
• Acid exposure: enamel feels rough or sensitive, often after soda, sports drinks, citrus, or vomiting/reflux.
• Frequent snacking or sipping: you do fine with meals, but you graze all day or keep a sweet or acidic drink nearby.
• Deep grooves or crowded areas: your molars keep getting cavities, or the same hard-to-clean spots come up again.
• Technique and timing mistakes: you brush regularly, but miss the gumline, skip morning or night, or brush right after acid.

To keep your friends. But for real, it’s to disrupt the plaque that sits on the surface of your teeth. Not only is it composed of food particles, but also bacteria and their byproducts (including the acidic byproduct that breaks down your teeth, causing cavities). Disrupting the plaque biofilm regularly by brushing and flossing helps to prevent cavities in this way.

— r/askdentists

Dry mouth is a common reason cavities keep happening

Saliva does more than wet your mouth. It buffers acid, helps clear food, and supplies minerals that support the tooth surface after everyday acid attacks.

The tell is a dry, sticky mouth, trouble swallowing dry foods, bad breath that comes back fast, or waking up thirsty. This often lines up with ADHD meds, antidepressants, antihistamines, some blood pressure drugs, mouth breathing, or sleeping with your mouth open.

If that sounds like you, this is the branch to take seriously first. If the dryness is new, severe, or tied to medication or medical symptoms, bring it up with your dentist or doctor rather than trying to shop your way out of it.

Yup. My husband brushes once a day and has never flossed in his life. Rarely goes to the dentist either. But when he does go: perfect teeth, no cavities. "I see you're brushing and flossing regularly! Great job!" 🙄

— r/ADHD

Acid and all-day sipping can overpower good brushing

A clean tooth can still spend too many hours in acid. Soda, energy drinks, juice, sparkling water with flavor, frequent citrus, reflux, and vomiting can all keep the pH low long enough for enamel to soften.

The pattern here is timing. You may be diligent with brushing, but if you sip acidic or sweet drinks over hours, your teeth keep getting hit again and again between brushings.

Another clue is sensitivity or a smooth worn look rather than just food-catching areas. After acid exposure, waiting a bit before brushing is usually gentler than scrubbing right away.

I'm 21 years old and have had two root canals and a crown. I have at least two cavities every time I go to the dentist. I brush twice a day and use mouth was in the morning. When I was 16 I had two cavities so I decided to cut out all pop and candy and start flossing on top of brushing and using mouth wash. I had four cavities the next time I went to the dentist. I can't catch a break...

— r/AskReddit

Frequent snacks and hidden sugar feed the problem between brushings

Cavities are not only about how well you clean. They are also about how often the bacteria in plaque get fed, especially by sticky carbs, sweets, and sweet drinks.

The tell is that you do the right things morning and night, but you snack constantly, chew sugary mints, use cough drops, or drink coffee with sugar through the day. Each exposure gives plaque another chance to make acid, and the biofilm grows back quickly after cleaning.

If this sounds familiar, work on fewer eating windows rather than harsher brushing. Technique still matters, but frequency is often the hidden part.

It’s not about brushing & flossing, it’s about doing it the right way! You do have multiple cavities :( check your diet and limit sugary drinks intake!

— r/askdentists

If your molars keep getting cavities, anatomy or missed spots may be the main issue

Molars are the usual troublemakers because grooves can be deep and hard to clean fully. Crowding, rotated teeth, braces, and a brushing pattern that misses the gumline or back molars make this more likely.

The clue is location. If the same molars keep getting cavities, or the decay shows up between teeth even though you brush a lot, think anatomy and access before you assume your whole routine is failing.

This is also where technique matters most. A careful angle at the gumline, enough time on the back teeth, and actual contact between floss and each tooth side can matter more than adding more products.

It’s really just a hygiene issue. She’s probably missing those spots repeatedly. You can’t get buildup and gingivitis like that red spot with good hygiene. Make sure she is flossing, and google the bass method of brushing. Brushing should include tooth structure AND the gum line.

— r/askdentists

What to try first when you have cavities despite brushing flossing

CariSpray is a nano-hydroxyapatite oral spray that adds moisture and leaves nano-hydroxyapatite on the enamel after the mouth goes quiet. It is alcohol-free, fluoride-free, requires no rinsing, and needs no sink, so you can use it away from a bathroom during dry mouth, long workdays, travel, braces, or other times on the go.

For the next two weeks, track three things: when your mouth feels dry, what you sip between meals, and which teeth are usually the problem. That simple record often tells you more than trying five new products at once.

If you already know the pattern, match the fix to it. Dry mouth needs saliva support and medication review, acid needs fewer and shorter exposures, snack-driven decay needs fewer eating windows, and repeat molar cavities need a closer look at access and technique.

100% my dentist says I have shit genetics and my mouth is just really hostile towards my teeth. Im brushing twice a day and flossing after every meal and getting ALLLLLL the cavities and dental issues. The only part that makes me angry is the fact that the MORE I do to keep my teeth clean the WORSE they get

— r/LifeProTips

Common questions

Why am I still getting cavities if I brush and floss every day?

Because brushing and flossing handle plaque, not every other risk. Dry mouth, acidic drinks, reflux, frequent snacking, deep grooves, and missed spots can still push the balance toward decay.

Can genetics cause cavities even with excellent oral hygiene?

Genetics probably play some part for some people, but it is often indirect. Tooth shape, saliva flow, bite, crowding, and how your mouth responds to plaque may matter more than a simple “bad teeth” label.

Why do my molars keep getting cavities?

Molars have pits and grooves that trap plaque more easily, and they are harder to see and reach. If the same molars keep getting cavities, anatomy or access is often a better explanation than poor effort.

Is brushing right after meals causing problems?

Right after an acidic drink or food, enamel can be temporarily softened. Waiting a bit before brushing is usually kinder than scrubbing immediately, especially if you have soda, citrus, or reflux in the picture.

Do I need a dentist if I keep getting cavities despite good oral hygiene?

Yes, especially if you have repeat cavities in the same area, obvious dry mouth, pain, sensitivity that lingers, or reflux or vomiting. That does not mean you have failed; it means the pattern needs a proper look.

Start by figuring out which pattern is yours. For most people, the first useful step is not brushing harder. It is noticing dryness, cutting the all-day sipping, or paying attention to which teeth keep showing up.

Pick one change this week and make it specific. If your mouth is dry, support moisture. If your molars are the problem, slow down there and check your flossing contact. If acid or reflux is in the mix, deal with that piece instead of blaming yourself.