A parent wrote me last week:
“We brush. We floss. We’ve switched toothpaste. But my kid still keeps getting cavities. What are we missing?”
I’ve heard that question hundreds of times. It’s always asked with the same mix of desperation and guilt.
And it always leads to the same truth: Cavities don’t just come from poor brushing. They come from daily habits that feel harmless.
Goldfish crackers. Gummy vitamins. Mouths that stay open through the night.
If you’ve done everything “right” and the cavities keep coming, this email is for you. Let’s talk about what actually makes a difference.
Let’s start with the daily multivitamin.
Back in the 90s, we gave our daughters Flintstones vitamins from Costco. I brushed their teeth every night and still saw that sticky film clinging to their molars like caramel. They never got cavities—but a dentist (that’s me) was brushing and flossing their teeth before bed. Most families don’t have that!
Now the problem is worse. Gummies are everywhere—multivitamins, probiotics, melatonin, magnesium. And while they seem like a smart choice, they weren’t designed with the mouth in mind.
Your kid’s tooth doesn’t care if it’s a gummy vitamin or a gummy worm. It reacts the same way.
If your child takes a gummy, here’s a better option: switch to a dental-friendly vitamin like Hiya. I like it because it’s sweetened with monk fruit—no sugar, no acidity, and it doesn’t feed the bacteria that cause cavities or disrupt the oral microbiome. For my eldest granddaughter—who struggled with cavities—this was a game changer. She had to give up her beloved Nordic Naturals gummies, and these made the transition easy.
If you remember one thing, make it this: A gummy vitamin every day does more damage than goldfish crackers once a month.
Now let’s talk about snacks.
We know juice and soda aren’t great. But most parents are surprised when I bring up goldfish.
Starchy snacks like crackers and pretzels break down into sugar—and they stick. They lodge into the grooves of baby molars and sit there for hours. That’s where cavities begin.
You don’t have to ban snacks. But you do need to think about texture. Ask: will this cling to teeth? Best way to know is to have some yourself! Does it stick to your teeth?
Better options? Moon Cheese which doesn’t stick and is made from just one ingredient—cheese. That means no added sugars, no starches, and nothing that feeds the bacteria behind cavities. Cheese is mineral-rich and helps stabilize oral pH, making it a truly tooth-friendly snack. Oh, and can’t forget my favorite—meat sticks!
A great “hack” is chewing xylitol gum in between meals (I like these ones because they’re free of essential oils, which disrupt the oral microbiome). Xylitol doesn’t just reduce cavity risk—it actively protects against it. In one study, xylitol was shown to inhibit the growth of bacteria in the upper airway, including Streptococcus pneumoniae and Haemophilus influenzae. Another long-term study found that xylitol gum helped reduce cavities even five years after kids stopped using it. And timing matters: research shows the earlier kids start chewing xylitol gum consistently, the stronger the long-term protection. This isn’t just about avoiding damage—it’s about helping the mouth stay healthy on its own. (PMID: 7486925, PMID: 8281565, PMID: 10096456)
Next: breathing.
If your child sleeps with their mouth open, brushing and flossing won’t be enough. Mouth breathing dries the tissues, lowers oral pH, and creates the ideal conditions for cavities to thrive.
You can’t fix this overnight, but you can start retraining the body.
Here’s what I recommend: During TV time, use MyoTape—a gentle, kid-safe tape that encourages lip closure while they sit and focus.
Screen time works well because they’re still, relaxed, and motivated. Breathing through the mouth is more noticeable in that state—and it gives you a quiet moment to build awareness and introduce a new habit without a power struggle.
Start with 10–15 minutes. Build from there.
If your child can’t keep their mouth closed comfortably, something deeper may be going on. Tongue ties. Enlarged adenoids. A narrow palate.
If that’s the case, see a functional dentist or airway-focused ENT. They can help uncover what’s making nasal breathing hard—and what to do next. You can find a provider through the Functional Dentist Directory or the AADSM (American Academy of Dental Sleep Medicine) directory. These are great starting points if you’re not sure who to turn to.
And finally: water.
If your child isn’t drinking much water during the day, they’re likely not producing enough saliva to protect their teeth.
Saliva is your child’s built-in defense system. It’s full of minerals that rebuild enamel. It buffers acid. It helps the mouth heal itself. But it only works if the body is hydrated.
Here’s what happens: every time your child eats—especially carbs or sugar—acid levels in the mouth rise. That acid pulls minerals from the enamel, weakening it. But saliva steps in. It brings back calcium, phosphate, and other minerals to rebuild the enamel. That’s remineralization. And when it works, it can stop cavities before they start.
But it can’t work if your child is dry.
When kids are dehydrated, saliva slows down. The pH drops. Acid builds. Bacteria thrive. It gets even worse at night, especially for mouth breathers. They wake up with a dry mouth and no protection.
The fix isn’t fancy. It’s good old fashioned water. Especially after meals and snacks, when acid is at its peak. And if your child resists water, give them a special straw or let them pick out a water bottle. I love this flavored electrolyte—it’s non-acidic with a pH of about 6.5, which is close to neutral and far safer than many popular electrolyte drinks that fall well below the critical pH threshold. Lemon Lime is my favorite flavor.
Brushing and flossing matter—but they’re not the whole picture.
If your child keeps getting cavities, don’t blame yourself. Look at the daily habits.
The good news is: you can shift the pattern. One decision, one habit, one replacement at a time. That’s how real prevention works. And it’s how your kid’s story changes.
Know a parent struggling with this? Forward this to them. It might be the first time they’ve heard a dentist connect the dots between everyday habits and tooth decay—with real solutions.
Talk soon,
Mark (Dr. B)
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P.S. Pictured below: real-world testing by the grandkid panel. No one’s asked for their gummies back. One of the perks of having a grandpa for a dentist is getting recruited for stuff like this. I was genuinely excited to find a kids’ vitamin made with teeth in mind—no sugar and nothing that undoes the work we’re doing to protect their mouths.
>>Try Hiya and get 50% off your first order.
