Don’t kiss your child on the lips

Posted by watchmen
May 9, 2024


By Dr. Joseph D. Lim

Joyce Kahng is a mother whose videos on TikTok went viral.

Her message: Under no circumstances should you kiss a child on the lips. The most viral of the video series had over 2.4 million views.

Joyce Kahng is also a 35-year-old cosmetic and restorative dentist who owns the Orange and Magnolia Dental Studio in Costa Mesa, California.

BuzzFeed interviewed Dr. Kahng who said that kissing on the lips (it could be sharing utensils as well) can transfer bacteria from mouth to mouth and may lead to cavities, especially in young children.

“Bacteria can transfer through salivary exchange and this is more common for children, less common for adults,” Dr. Kahng explained. “Children are not actually born with the bacteria that cause cavities. These bacteria are transferred to them at an early age, usually from their caregiver through activities like kissing and sharing utensils.”

After the age of four, she said, a child’s oral microbiome has matured. The oral biome, the community of microorganisms that resides in the oral cavity, “is unique to them, making them more resistant during times of salivary exchange.”

Dr. Kahng points to streptococcus mutans, a bacterium she describes as the major cause of tooth decay.

“These bacteria feed off of sugars in our diet and produce acid as a byproduct,” she told BuzzFeed. “Acid produced by these bacteria will dissolve the enamel layer and form a cavity … the more of this bacteria we have, the harder it will be to prevent decay.”

“Sometimes it’s not easy to apply the understanding of science to real life (whether you’re a doctor or not). I then realized a lot of people don’t know this science at all — I myself only learned it in dental school.”

In an experiment in dental school, the young Joyce Kahng and fellow students swabbed their mouths and separately grew the saliva they collected in a petri dish. Under a microscope, she discovered the large amount of bacteria in her saliva, the bacteria potential causes of cavities.

“As a dentist, one of my goals is to educate others, and I don’t think this type of information should be a privilege,” she told BuzzFeed in an article carried by yahoolife.

“I didn’t want to shame anyone or make any moms feel bad if they’d already been sharing food, so I kept the videos less about what you ‘should’ do and more about what I have personally chosen to do.”

“It all starts with the oral health of the parents. I recommend my patients try to take care of their own active oral disease prior to pregnancy. This sets up good habits and an awareness to pass forward to their children. When I find out one of my patients is having a baby, I try to have a discussion with them about when they can start bringing their child to the dentist and start introducing brushing. Being on the front end of things is the goal — education is power!”


Dr. Joseph D. Lim is the former Associate Dean of the College of Dentistry, University of the East; former Dean, College of Dentistry, National University; Past President and Honorary Fellow of the Asian Oral Implant Academy; Honorary Fellow of the Japan College of Oral Implantologists; and Honorary Life Member of the Thai Association of Dental Implantology. For questions on dental health, e-mail or text 0917-8591515.


Dr. Kenneth Lester Lim, BS-MMG, DDM, MSc-OI, graduated Doctor of Dental Medicine, University of the Philippines College of Dentistry, Manila, 2011; Bachelor of Science in Marketing Management, De La Salle University, Manila, 2002; and Master of Science (MSc.) in Oral Implantology, Goethe University, Frankfurt, Germany, 2019. He is an Associate professor; Fellow, International Congress of Oral Implantologists; Member, American Academy of Implant Dentistry and Philippine College of Oral Implantologists. For questions on dental health, e-mail

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