The short answer: Some popular tooth facts hold up and some don’t. True: enamel is the hardest tissue in the body, you get only two sets of teeth (20 baby teeth and 32 adult teeth), you make almost no saliva while you sleep, tooth decay is the most common health condition in the world, and the first dental college opened in Baltimore in 1840. False or exaggerated: teeth are not bones, the ancient Egyptians didn’t invent toothpaste as we know it, the oldest true dental implants are about 1,400 years old rather than 4,000, and there is no good evidence that chocolate protects teeth or that tongue prints are as unique as fingerprints.
Dental trivia spreads quickly online, but not all of it is accurate. We checked 10 popular claims about teeth against scientific reviews, dental organizations and historical sources, and gave each a verdict: true, false, exaggerated or unproven.
For each claim, we looked for systematic reviews and guidance from major health and dental organizations or, for historical claims, peer-reviewed histories, and where the evidence is thin we say so. Several of these facts also carry a practical lesson for looking after your teeth. For myths about brushing, flossing and dental care itself, see our companion guide to common dental myths.
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Is tooth enamel the hardest substance in the body?
Verdict: True. Dental enamel is the hardest and most mineralized tissue in the body, which lets teeth withstand a lifetime of chewing (Lacruz et al., 2017). It is not indestructible, though: acids from food and drink, or from stomach acid in people with reflux, can gradually wear it away (Carvalho et al., 2015).
Are teeth bones?
Verdict: False. Teeth and bones are both hard and mineral-rich, but they are built differently. Enamel is made by specialized cells called ameloblasts, and once the enamel has formed, most of those cells die off and the rest are shed when the tooth comes into the mouth (Lacruz et al., 2017). With no cells left to rebuild it, lost enamel can’t grow back, which is why tooth erosion is permanent (American Dental Association, n.d.).
The practical lesson is to protect the enamel you have: fluoride toothpaste helps keep teeth strong (Walsh et al., 2019), and limiting acidic drinks reduces wear (American Dental Association, n.d.). See how fluoride protects teeth.
Do you only get two sets of teeth?
Verdict: True. Most people have 20 baby (primary) teeth, which start to come in at about 6 months of age, and by about age 21 all 32 permanent teeth have usually come in (American Dental Association, n.d.-b). There is no third set, so adult teeth have to last a lifetime.
Baby teeth still need daily care even though they eventually fall out. Our parent’s guide to kids’ teeth covers how to care for them.
Do you stop making saliva when you sleep?
Verdict: Mostly true. Saliva flow is negligible during sleep, so its protective effects are largely lost overnight. That is why the most important time to brush is just before bed (Dawes, 2008). Saliva normally protects teeth by buffering acids, clearing sugar and food from the mouth and supplying minerals that help repair early damage (Dawes et al., 2015).
During the day, chewing sugar-free gum or sucking sugar-free candies stimulates saliva flow, which benefits both teeth and gums (Dawes, 2008). Our guide to saliva and dry mouth explains why saliva matters and what to do if your mouth often feels dry.
Is tooth decay the most common disease in the world?
Verdict: True. Untreated tooth decay in permanent teeth is the most common health condition worldwide according to the Global Burden of Disease study, and oral diseases as a whole affect nearly 3.7 billion people (World Health Organization, 2025). Our overview of the most common dental problems and our guide to preventing cavities explain what you can do about it.
The good news is that decay is largely preventable. Fluoride toothpaste prevents it better than toothpaste without fluoride (Walsh et al., 2019), and cutting back on sugar lowers the risk (Moynihan & Kelly, 2014).
Are tongue prints as unique as fingerprints?
Verdict: Unproven. The shape and surface features of the tongue, such as fissures, do vary from person to person, and researchers have explored tongue prints as a possible way to identify people. However, the evidence so far comes from small pilot studies, and larger studies are needed before tongue prints can be called truly unique (Jeddy et al., 2017).
Did the ancient Egyptians invent toothpaste?
Verdict: Exaggerated. Tooth-cleaning pastes and powders have been used for several thousand years, and early versions were made from ingredients such as crushed eggshells or ashes (Lippert, 2013). In ancient Egypt, though, dental care relied mainly on medicinal preparations applied to the gums or used as mouthwashes (Forshaw, 2009), and the popular claim that the Egyptians invented toothpaste around 5000 BC is not well documented. Evidence from mummies and skeletal remains suggests that many ancient Egyptians suffered from widespread and painful dental disease, which the treatments of the time did little to relieve (Forshaw, 2009).
Modern toothpaste is a very different product. Today’s formulas can contain more than 20 ingredients, including compounds that target decay, gum disease, bad breath, tartar, erosion and sensitivity (Lippert, 2013), and toothpaste with fluoride prevents decay better than toothpaste without it (Walsh et al., 2019). For the parallel story of the toothbrush, see who invented the toothbrush.
Are dental implants 4,000 years old?
Verdict: Exaggerated. Replacing and stabilizing teeth does have ancient roots: a historical review notes that around 2500 BC the ancient Egyptians used gold wire to stabilize loose teeth. But it dates the first evidence of true dental implants to around 600 AD, when the Maya used pieces of shell to replace lower teeth, followed by a stone implant from around 800 AD found in what is now Honduras (Abraham, 2014).
Modern implants are made very differently, and the same review traces how today’s titanium implants and their surface treatments developed (Abraham, 2014). If you are considering one, see do dental implants hurt.
Is dark chocolate good for your teeth?
Verdict: Unproven. In laboratory studies, compounds from cocoa called polyphenols reduced biofilm formation and acid production by cavity-causing bacteria (Ferrazzano et al., 2009), but this has not been shown to protect teeth in people. Most chocolate also contains plenty of sugar, and higher sugar intake is linked to more tooth decay (Moynihan & Kelly, 2014).
If you enjoy chocolate, have it with a meal rather than nibbling it throughout the day, since how often you have sugar matters as well as how much (Office for Health Improvement and Disparities, 2025), and keeping food in your mouth as briefly as possible is better for your teeth (Dawes, 2008). Our guide to foods for healthy teeth has more on smart swaps.
Was the world’s first dental school founded in 1840?
Verdict: True. The Baltimore College of Dental Surgery, established in 1840 and now the University of Maryland School of Dentistry, describes itself as the world’s first dental college (University of Maryland School of Dentistry, n.d.). It marked an early step in making dentistry a profession with its own formal training.
What it means for you
If you want to protect your enamel
Because enamel can’t grow back, brush twice a day with fluoride toothpaste and rinse with water after acidic drinks (Walsh et al., 2019; American Dental Association, n.d.).
If you only brush once a day
Make it the bedtime brush, since saliva flow is negligible during sleep (Dawes, 2008), and aim to add a second session; our daily dental hygiene routine shows how.
If you love chocolate
Enjoy it with meals rather than as an all-day snack, and don’t count on cocoa to protect your teeth (Ferrazzano et al., 2009; Office for Health Improvement and Disparities, 2025).
Questions to ask your dentist
- Do I have any signs of enamel wear?
- Are my baby teeth or my child’s adult teeth coming in on schedule?
- Am I getting enough fluoride?
- What changes to my diet would help my teeth most?
When to see a dentist
Book a dental visit if:
- Your teeth are sensitive to hot, cold or sweet foods.
- You notice dark spots, holes or worn edges on your teeth.
- Your child’s teeth are coming in very late or look discolored.
- Your gums bleed when you brush or floss.
For severe pain, swelling or a broken tooth, see what to do in a dental emergency.
The bottom line
Several popular tooth facts are true: enamel is the hardest tissue in the body, you get only two sets of teeth, saliva almost stops during sleep, tooth decay is the world’s most common health condition, and the first dental college opened in 1840. Others are exaggerated or unproven, including claims about Egyptian toothpaste, 4,000-year-old implants, unique tongue prints and tooth-friendly chocolate. The most useful takeaway: enamel can’t regrow, so protect it with fluoride toothpaste, less sugar and a good bedtime brush.
References
Abraham CM. (2014). A brief historical perspective on dental implants, their surface coatings and treatments. The Open Dentistry Journal, 8, 50–55. https://doi.org/10.2174/1874210601408010050
American Dental Association. (n.d.). Erosion: What you eat and drink can impact teeth. MouthHealthy. https://www.mouthhealthy.org/all-topics-a-z/dietary-acids-and-your-teeth
American Dental Association. (n.d.-b). Eruption charts. MouthHealthy. https://www.mouthhealthy.org/all-topics-a-z/eruption-charts
Carvalho TS, Colon P, Ganss C, Huysmans MC, Lussi A, Schlueter N, et al. (2015). Consensus report of the European Federation of Conservative Dentistry: Erosive tooth wear, diagnosis and management. Clinical Oral Investigations, 19(7), 1557–1561. https://doi.org/10.1007/s00784-015-1511-7
Dawes C. (2008). Salivary flow patterns and the health of hard and soft oral tissues. Journal of the American Dental Association, 139(Suppl), 18S–24S. https://doi.org/10.14219/jada.archive.2008.0351
Dawes C, Pedersen AML, Villa A, Ekström J, Proctor GB, Vissink A, et al. (2015). The functions of human saliva: A review sponsored by the World Workshop on Oral Medicine VI. Archives of Oral Biology, 60(6), 863–874. https://doi.org/10.1016/j.archoralbio.2015.03.004
Ferrazzano GF, Amato I, Ingenito A, De Natale A, Pollio A. (2009). Anti-cariogenic effects of polyphenols from plant stimulant beverages (cocoa, coffee, tea). Fitoterapia, 80(5), 255–262. https://doi.org/10.1016/j.fitote.2009.04.006
Forshaw RJ. (2009). The practice of dentistry in ancient Egypt. British Dental Journal, 206(9), 481–486. https://doi.org/10.1038/sj.bdj.2009.355
Jeddy N, Radhika T, Nithya S. (2017). Tongue prints in biometric authentication: A pilot study. Journal of Oral and Maxillofacial Pathology, 21(1), 176–179. https://doi.org/10.4103/jomfp.JOMFP_185_15
Lacruz RS, Habelitz S, Wright JT, Paine ML. (2017). Dental enamel formation and implications for oral health and disease. Physiological Reviews, 97(3), 939–993. https://doi.org/10.1152/physrev.00030.2016
Lippert F. (2013). An introduction to toothpaste: Its purpose, history and ingredients. Monographs in Oral Science, 23, 1–14. https://doi.org/10.1159/000350456
Moynihan PJ, Kelly SA. (2014). Effect on caries of restricting sugars intake: Systematic review to inform WHO guidelines. Journal of Dental Research, 93(1), 8–18. https://doi.org/10.1177/0022034513508954
Office for Health Improvement and Disparities. (2025). Delivering better oral health: An evidence-based toolkit for prevention. Chapter 10: Healthier eating. https://www.gov.uk/government/publications/delivering-better-oral-health-an-evidence-based-toolkit-for-prevention/chapter-10-healthier-eating
University of Maryland School of Dentistry. (n.d.). About UMSOD. https://www.dental.umaryland.edu/about/
Walsh T, Worthington HV, Glenny AM, Marinho VC, Jeroncic A. (2019). Fluoride toothpastes of different concentrations for preventing dental caries. Cochrane Database of Systematic Reviews, 3(3), CD007868. https://doi.org/10.1002/14651858.CD007868.pub3
World Health Organization. (2025). Oral health [Fact sheet]. https://www.who.int/news-room/fact-sheets/detail/oral-health
References checked October 2026 · Editorial policy · Report a correction
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