Why You’re Getting Cavities Even Though You Brush Twice a Day

You brush every morning. You brush every night. You even floss sometimes. So why are you still getting cavities?

It’s a frustrating — and surprisingly common — situation. Many patients are diligent with their daily brushing habits, yet still find themselves facing new areas of decay at their regular dental visits. The truth is, while brushing is essential, it’s only one part of the cavity-prevention puzzle.

If you’ve ever wondered why your efforts aren’t translating into better outcomes, here are some of the most common (and overlooked) reasons cavities might still be appearing.

1. You’re brushing — but not effectively

Brushing twice a day is great. But if you’re rushing through it, missing spots, or using the wrong technique, your efforts might not be doing what you think they are.

Common issues include:

• Brushing for less than two minutes
• Not reaching the gum line or back teeth
• Using a hard-bristled brush that’s too abrasive
• Brushing straight after acidic foods or drinks (which can weaken enamel)
• Not replacing your toothbrush every 3–4 months

Try switching to a soft-bristled brush or electric toothbrush, and focus on slow, circular motions that follow the shape of your teeth and gums.

2. You’re missing between the teeth

Toothbrush bristles can’t reach between your teeth — and that’s where food particles and plaque love to hide. If you’re not flossing or using interdental brushes, you could be leaving around 30% of the tooth surface untouched.

Plaque left between the teeth quickly turns into tartar, which can trap bacteria and lead to decay. Over time, this can cause cavities to form in areas that aren’t visible or painful until they’re advanced.

Even flossing a few times a week is better than not at all. If traditional floss is tricky, try floss picks or interdental brushes as a more user-friendly alternative.

3. Your diet might be working against you

What you eat — and how often you eat — can have a big impact on your risk of cavities. Frequent snacking or sipping on sugary or acidic drinks creates repeated acid attacks on the enamel, which weakens the teeth and makes them more vulnerable.

Key culprits include:

• Soft drinks (including “sugar-free” versions, which are still acidic)
• Fruit juices
• Flavoured waters and sports drinks
• Lollies and sticky snacks
• Dried fruit
• Frequent grazing between meals

It’s not just about how much sugar you consume — it’s how often. Giving your teeth a break between eating or drinking gives saliva time to neutralise acids and begin repairing enamel.

4. Your saliva may not be doing its job

Saliva plays a crucial role in protecting your teeth. It helps wash away food, neutralise acid, and deliver minerals that strengthen enamel. But if you have dry mouth — whether due to medications, stress, mouth breathing, or certain health conditions — your teeth are more exposed.

Signs of dry mouth include:

• Constant thirst or dryness
• Bad breath
• Burning or dry tongue
• Difficulty swallowing or speaking

If you’re experiencing dry mouth regularly, let your dentist know. There are treatments and strategies that can help improve moisture levels and reduce your risk of decay.

5. You’re genetically more prone to decay

Some people have softer enamel. Others naturally have deeper grooves or pits in their molars, where bacteria can collect. Even your unique oral microbiome — the balance of bacteria in your mouth — can affect your likelihood of developing cavities.

While you can’t change your genetics, you can work with your dentist to create a prevention plan tailored to your needs. That might include more frequent cleans, fluoride applications, or protective sealants to help shield vulnerable areas.

6. You’re skipping regular professional cleans

Even with great brushing and flossing at home, plaque and tartar still build up in places you can’t reach — especially below the gum line or in tight crevices. Once tartar hardens, it can’t be removed with a toothbrush.

Regular professional cleans (usually every six months) are essential for:

• Removing hardened plaque (calculus)
• Reaching areas you miss at home
• Identifying early signs of decay or gum issues
• Giving your enamel a clean, fresh surface

If it’s been more than six months since your last visit, it’s worth booking in.

Don’t give up — just adjust the plan

Getting a cavity doesn’t mean you’ve failed. It simply means your current routine might need a little fine-tuning.

Modern dentistry is about prevention, not blame. By understanding your unique risk factors — from diet to brushing habits to saliva levels — we can work with you to protect your smile more effectively.

Let’s personalise your prevention

You’re already putting in the effort. Let’s make sure it’s working for you. Whether you need a better toothbrush, dietary advice, or just a refresh of your current routine, we’re here to help.

Visit us for a personalised check-up and clean, and let’s keep your smile strong — for the long term.