This article originally appeared on Business Insider, August 14th, 2021.

Kissing someone with poor dental hygiene isn’t just gross, it can actually damage your smile, according to Dr. Tina Saw, cosmetic dentist and founder of Oral Genome.

Bad dental hygiene can lead to plaque buildup, gum disease, and can create a breeding ground for bacteria. If you kiss your partner and swap saliva, you risk transferring it.

“Saliva not only keeps our mouths moist, but it also is a great medium for oral bacteria to live and thrive in,” Saw told Insider. “Kissing for 10 seconds can exchange about 80 million bacteria and microorganisms.”

If your partner needs to improve their dental hygiene routine, here are tips to approach the topic with them.

Kissing someone with poor oral hygiene can give you more plaque buildup and exposes you to bad bacteria over time

While having good bacteria is normal, kissing someone with bad bacteria in their mouth can affect your own dental hygiene.

This bacteria can cause bad breath, gum disease, and increased plaque build up if you aren’t extra diligent about taking care of your teeth.

Be gentle when discussing dental hygiene with your partner

There’s no way to not exchange bacteria when you kiss your partner, according to Saw. But there are ways to keep the bacteria in check.

“This starts with good dental hygiene, which includes brushing at least twice a day, flossing, and seeing your dentist at least twice a year for a checkup and cleaning,” Saw said.

Talking to your partner about dental hygiene can be a touchy subject, so approach the issue with sensitivity.

“This can be quite a touchy subject if your boo’s oral hygiene is poor,” Saw said. “Talk to them gently about the subject and assist with developing a plan of good oral hygiene habits. Encourage them to eat healthy, exercise, and brush and floss with you.”

Saw said foods like cheese and nuts can be a great way to boost dental health. Scheduling dental appointments together can also be a bonding experience to help keep each other accountable for improving your dental health.

Even doing daily dental hygiene routines together can be a way to make it more fun.

“Brush together twice a day and two minutes each time,” Saw said. “Floss by having the floss ‘hug’ your teeth and create a C-shaped curve to get into the gum pockets.”

This article originally appeared on Business Insider, August 14th, 2021.