#166 – Patricia Corby, D.D.S.: Importance of oral health, best hygiene practices, and the relationship between poor oral health and systemic disease

“You can maintain optimal oral health just by brushing teeth, by flossing really well, and having good nutrition.” —Pat Corby

Read Time 20 minutes

Dr. Patricia Corby is Associate Professor of Oral Medicine and Associate Dean of Translational Research at Penn Dental Medicine. Her work focuses on the value of integrating dental services into other healthcare and public health settings. In this episode, Pat provides an overview of dental anatomy, the importance of oral hygiene to overall health, and the association of poor oral health and systemic diseases like cancer and diabetes. She addresses tooth decay, oral hygiene in children, the utility of dental products, and ideal oral care regimens for different populations. She also discusses issues specific to immunocompromised patients and those with chronic illnesses as well as her own research with cancer patients undergoing radiation treatment. 



We discuss:

  • Anatomy of teeth and the purpose of the dental pulp—a highly vascularized and innervated region of the tooth [3:00];
  • Types of teeth and the different purpose they serve [14:15];
  • Anatomy of the oral cavity, bacteria in the mouth, and what a healthy mouth looks like [18:10];
  • Pat’s study demonstrating the importance of flossing [23:00];
  • Detrimental effects of sugar and the importance of fluoride and oral hygiene [31:45];
  • Oral health challenges for cancer patients and immunocompromised people [39:45];
  • Pat’s current research on cancer patients undergoing radiation treatment and the oral health risks associated with human papilloma virus (HPV) [50:00];
  • Periodontal disease: caries and root canals [57:30];
  • The relationship between poor oral health and systemic health diseases [1:11:00];
  • Potential connection between oral hygiene and COVID-19 [1:17:45];
  • Dry mouth leading to oral infections and ways to prevent it [1:22:30];
  • What determines the appearance of teeth, methods of teeth whitening, and whether you should remove mercury fillings [1:27:30];
  • Importance of fluoride for preventing tooth decay, and dental care for children [1:32:45];
  • Useful dental products: floss, electrics toothbrushes, and more [1:39:15];
  • Ideal oral care regimens [1:47:30]; and
  • More.


Anatomy of teeth and the purpose of the dental pulp—a highly vascularized and innervated region of the tooth [3:00]

  • Pat likes to talk about oral health with MDs because the connection to health is important
  • Peter has long wanted to discuss oral health, which is “a very underappreciated part of health” that is more than just cavities and cosmetic concerns

Pat’s background

  • Pat grew up in Brazil
  • Wanted a career involving systemic health
  • specialty is in periodontics and implant dentistry
  • Always wanted to do research
  • Stayed in US because so many professional opportunities
  • Peter mentions the anniversary of the death of Ayrton Senna
    • Pat was watching the race on TV
    • Peter says he’s never met a Brazilian person who was over 5 on that day who doesn’t remember it
    • Peter says Senna is his personal hero, and he is wearing a Senna bracelet for the occasion 
  • Peter did not go to the dentist for about 10 years during medical school and residency, but now he takes dental care very seriously

Anatomy of teeth [6:15]

  • The periodontium is very complex system
  • Peter points out that there’s a vascular supply quite high in the tooth even though many people might assume that the white crown is just bone
  • Tooth enamel, made of minerals, is the hardest surface in the human body

Figure 1. Individual tooth anatomy. Image courtesy of Pat Corby.

  • On the top is enamel and cementum (around the root), then dentin, then pulp
    • The enamel protects the layers underneath (hardest surface of the human body)
    • The second layer provides cushioning and is hyper sensitive
    • the heart of the tooth is the pulp, which has a lot of nerves – explains why tooth pain can be so bad
    • ligaments around the roots provide cushioning against impact

Figure 2. Anatomy of a tooth showing cementum. Image credit: Wikipedia

The role of the nervous connection and vascular supply to the tooth [10:40]

  • Tooth decay
    • Tooth decay first affects the pulp
    • If you excise the pulp, you can preserve the root

“The way you want to think in dentistry is that … you want to preserve function.” —Pat Corby

  • Try not to extract teeth because the space they hold is important
  • If necessary, do a root canal or put in an artificial crown

Figure 3. Progression of a root canal treatment. Images courtesy of Pat Corby.

  • Put implants in if you have to extract an entire tooth; not as good as a real tooth but can still hold the space and provide some function
  • Can still get inflammatory periodontal disease with an implant
  • Peter wonders why teeth are so highly innervated
    • Implants without nerves can still break down food
    • Our fingers are highly innervated because we need fine motor control, but why so much beneath the hard enamel?
    • Pat says it preserves blood flow and connection with the immune response to fight infection

Function and innervation of the pulp (this section contains additional information provided by Pat after the podcast was recorded)

  • The main four functions of the pulp:
    • formation of dentin – one the most important roles, carried out by odontoblasts
    • support of dentin through nutritional support (albumin, transferrin, tenascin, and other proteoglycans)
    • innervation of the tooth
    • immune system protection of tooth: occurs through the development of new dentin, which can provide a barrier between irritants and slow the rate of carious decay
  • Two main types of nerves are found in the pulp:
    • Sympathetic autonomic fibers to the smooth muscle cells of pulp arterioles control contractile forces that regulate blood flow
    • Afferent fibers are involved in temperature sensing and mechanical nociception
  • Peter reflects that dental pain seems to serve as such an early warning indicator as a breach of a barrier 
  • He says, “Having been through so many miserable dental experiences, I’ve often cursed our evolutionary gods for giving us so much innervation in that tooth”

{end of show notes preview}

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Patricia Corby, D.D.S., M.S.

Dr. Patricia Corby is an Associate Professor of Oral Medicine and the Associate Dean of Translational Research at the University of Pennsylvania Dental Medicine. She is also the Director of the Penn Dental Medicine Center for Clinical and Translational Research. She is an experienced researcher with over 20 years of experience designing and running high-impact clinical research projects and has served as Principal Investigator, Co-Investigator, or Consultant on a number of projects funded by the National Institutes of Health (NIH), foundations, and industry.  Dr. Corby’s work focuses on the value of integrating medical and dental services in different healthcare and public health settings to prevent systemic complications of populations with unmet oral health needs and associated chronic diseases.  After receiving her DDS and completing her residency in Periodontics and Implants in her native Brazil, she obtained her MS in Biomedical Informatics from the University of Pittsburgh School of Medicine completed a postdoctoral training in Molecular Biology and Microbial Genetics at Harvard University and the Forsyth Institute.

Professional website: https://www.dental.upenn.edu/faculty/patricia-corby/

Disclaimer: This blog is for general informational purposes only and does not constitute the practice of medicine, nursing or other professional health care services, including the giving of medical advice, and no doctor/patient relationship is formed. The use of information on this blog or materials linked from this blog is at the user's own risk. The content of this blog is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Users should not disregard, or delay in obtaining, medical advice for any medical condition they may have, and should seek the assistance of their health care professionals for any such conditions.


  1. Just a few comments. Children under 5 cannot “spit out” effectively and should therefore use fluoride free toothpaste. As you mentioned, brushing and flossing is the most important, paste is secondary and one should be careful of ingredients that many people have sensitivities to, like sodium laurel sulfate. It’s recommended to floss first, to move bacteria laden plaque to a surface of the tooth that can be accessed by the tooth brush.

    Why can tooth pain be so excruciating? When the pulp becomes inflamed it has no place to swell because it is encased in a hard shell (the tooth), similar to an injury to a nail bed that is relieved when pressure can be released.

    Figure 1. Periodontal ligament is the ligament that attaches the tooth to the bone. The figure identifies the bone, not the ligament. Periodontal ligament is lost as periodontal disease progresses. Healthy periodontal pockets (aka, sulcus or gingival pockets) are not over 3mm probing depth. The podcast sounded like ANY periodontal pockets were pathological. As an aside, one of the reasons implants can be problematic is because they have no periodontal ligament, which, in health, keeps the pocket depth at a cleansable 3mm or less. Therefore, implants require more careful maintenance.

    Our recommendation is tongue scraping over brushing, it’s more thorough. Just hide it from your wife 🙂 Our recommended floss is a woven coconut fiber like Coco floss unless it shreds too much. Reason is that it “grabs” plaque better than a teflon floss.

    There are ultraviolet tooth brush sterilizers out there, in case you want to skip the soap.

    You asked about systemic health effects of root canal therapy. You and Pat made an excellent point, that root canals should be done by an endodontist who uses a microscope. That said, the bacteria that are specific to periapical pathology (the infection at the root tip secondary to pulp necrosis) as well as periodontal disease are also a significant player in driving heart attack risk. DNA analysis was done on arterial blood samples and culprit blood clots. The concentration of oral pathogens was 16 times greater in the clot than in the arterial blood. Researchers examining nine clots with an electron microscope found fragments of oral bacateria in 100 percent of the clots, some of which were still whole. This said, it is not uncommon for a tooth to have a significant infection without ANY symptoms. Since I started using a CBCT in 2018 I’ve discovered many lesions on previously untreated teeth that I would not have seen on traditional periapical radiographs. Some of these infections have been quite significant extending into the maxillary sinus.

    Thanks for including oral health in your podcast!
    Kim Rioux DDS

    • I’m going to sound so naive but this conversation has thrown me for 2 main reasons. And to be clear, I’m not an expert but have read quite in-depth as I have some historical root canals I need to decide what to do with.

      Issue 1 is – since when is fluoride good for teeth and when was it proven to improve tooth health?

      Issue 2 is around root canal treated teeth and the possible residual anaerobic bacteria in the tubules of the dead tooth. How would that bacteria be cleared by the body in the absence of blood supply due to removal of the nerve and blood vessels?

      Please be as blunt or as basic as you need to be to make a clear case here for either. I don’t even know where to begin to pull on that thread to get to a more logical truth.

      • Fluoride , like any drug in a therapeutic dose is safe. Fluoride changes the main mineral component in bone and teeth hydroxyapatite (HA) to Hydroxyfluoroapetite (HFA). HFA is less soluble and more resistant to demineralization than HA. Consequently when fluoride is used and applied to teeth , the teeth are much more resistant to dental decay. Dental decay is a acid demineralization to teeth. Fluoride is best delivered systemically in the correct safe dosage in the developing child when the teeth are developing . In adults bets applied as a gel for 10 minute increments or as a varnish.
        With regard to root canal treatments. During the process the canal system of the tooth is cleaned out mechanically and then flushed with sterilizing solutions for a period of time. These solutions will enter into the whole canal complex and into the dentinal tubules to sterilize that environment. The tooth is not dead , it is an organ where the vital components i.e. nerve, lymph and blood supply has been removed. The outer layer of the root is surrounded by live cells (cementum) , periodontal ligament fibers. The immune system has access to the complete root surface. There is still proprioceptive sensation to a tooth with a root canal treatment
        Marc Alexander (Prosthodontist)

  2. This was great,Peter, thank you. I was hoping she’d talk about oil pulling with coconut oil.

  3. What about topical antioxidants on gum tissues? (like the kind made by PerioSciences). I’m familiar with the benefits of antioxidants with respect to dermatology, but I’m curious if it translates.

    • The water pic will remove food particles and solid debris. It will not remove the bacterial plaque. The bacteria colonize on a primary glycoprotein layer on the teeth, called the pellicle . This bacterial colony, which is very sticky , develops to an established plaque layer within hours after cleaning teeth. Plaque has to be physically removed, best done with floss and a brush 2 to 3 times daily.

    • I tell my patients that a waterpik is like a car wash where you take your car and you wash it yourself with the spray wand (not using the brush). The car may look clean but after it dries you can still see a grime film that you can wipe off with your finger and see that you haven’t removed the “grime layer”. A waterpik is better than nothing but it needs the mechanical action to break up that biofilm and get oxygen in there to prevent the proliferation of the anaerobes.

    • molars have a fluting in-between, the water pic will not access. the best is a small “bottle brush ” called an inter proximal brush as the bristles open up and clean the fluting, do not force one in , best to get a curaprox as measured by a hygienist.

    • They discussed this: listen to the section “Ideal oral care regimens” beginning [1:47:30].

  4. This would’ve been the perfect time to ask about nicotine gum / nicotine pouches (Zyn) and gum health

  5. This would’ve been the perfect time to ask about nicotine gum / nicotine pouches (Zyn) and gum health – missed opportunity

  6. Teeth are organs. They are 1 of 2 organs that are called end-organs, the other being the kidney. These end-organs have one portal of entry of vascular, lymphatic and nerve supply. When teeth are traumatized or assaulted by bacteria (via dental caries), the inflammatory response that occurs will cause engorgement of this confined system (pulp). Thereby decreasing blood flow and hindering access of our immune system to clear out the infectious agents. This leads to pulp death, and a harbor for bacterial colonization and abscess formation. The bacteria will seed into the surrounding periapical bone space which causes acute infection or chronic infection ( the immune system is doing just enough to prevent fast growth and pain) chronic abscesses can remain a symptomatic for years. Undesirable systemic inflammatory consequences.
    Dentists not only repair and reconstruct damaged teeth, but enable patients to maintain optimal oral health. This philosophy is in line with Peters approach to patient care. Prophylactic and preventative care is essential for longevity and wellness. Peter I thank you for your exemplary contribution to medical science.
    Marc Alexander (Prosthodontist)
    Marc Alexander (Prosthodontist)

  7. My dentist doesn’t believe that I seldom floss and only brush at night before bed (Xylitol fluoride-free toothpaste). I had terrible oral health ten years ago, then I stopped eating sugars, grains, vegetable seed oils. Started keto/primal and taking fat-soluble vitamins, especially K2. Two of my brothers started on just D3/K2 and separately reported a year later that their dentist noticed a significant improvement in their oral health.

  8. Unfortunately I have way too
    Much dental experience and this episode although an okay basic intro falls short . And fluoride is definitely not necessary for healthy teeth . Fluoride is a byproduct of the aluminium mining industry. It’s more about acid alkaline balance and consumption of excess sugary. Also the root canal information was poor and they are basically dead organs in our body . I am
    On the process of replacing mine with ceramic implants. Biological dentistry is the future and this podcast was disappointing. It also equated those who question root canal safety with anti-vaxers. That’s lame and lazy…

    That’s all I have to say.

  9. You can get more information about the anthropology from University of Pennsylvania museum. This was introduced in the good book Breath by James Nestor. There is information that our ancestors has pretty good teeth prior to modern diet.

  10. Peter’s comment about fluoride seems like an unusual lack of knowledge about an important and potentially toxic element. The potential displacement of other halides on thyroid function and children should be considered.
    Cochrane review found little support for this and despite her contention, many countries do not follow the practice of Flouride in public water. Like Austin Texas.

  11. As a dentist, I very much appreciated a podcast on oral health! Dr. Corby covered a lot of good information, but I would love to see another podcast or two covering more information on the 1) oral-systemic connection, 2) the importance of diet to oral health, and 3) airway/breathing.

    1) I think a podcast with Dr. Bradley Bale and Peter Attia would be fantastic. He is the author of the book “Beat the Heart Attack Gene” and an excellent paper titled “High-risk periodontal pathogens contribute to the pathogenesis of atherosclerosis”. He is well known and very respected in the dental community on the link between heart disease and oral health.

    2) It sounds pretty controversial, but compared to diet, the importance of brushing and flossing is very overrated. Steven Lin, author of “The Dental Diet” would be a great guest for an interview.

    3) Jaw anatomy has a large impact on how we breathe, and our jaws are significantly smaller than our ancestors (why our wisdom teeth rarely have room anymore). Dentists, orthodontists, oral surgeons can make a huge impact on the developing jaws on children, as well as those with sleep apnea or other breathing disorders. Jeff Rouse (prosthodontist), Steven Park (ENT), and James Nestor (author) would be fantastic guests for podcast interviews.

    The health of the mouth is a window to the health of the body, and the information you can glean from an oral exam is simply amazing. I would love to hear more podcasts on these topics! Thanks for all you do Peter and team!

  12. Profoundly disappointing. Though Dr, Corby was informative and well spoken, she , as well as Dr. Atilla have been duped . Humans didn’t need to brush their teeth until recently, when we changed our lifestyles profoundly by becoming modernized. To mention epigenetics, and not Dr. Weston A Price, the father of modern epigenetics is a sad testament to Dr. Attia’s limited belief in ancestral health. He has conveniently accepted the biohacking worlds understanding of a ketogenic diet, and intermittent fasting, over the standard American diet, yet that’s where his investigation to the subversion of our health ends. Peter, as one Canadian to another, take a deeper dive, and ask yourself why you didn’t learn about what Price investigated. I also salute your dentist that had the common sense to replace your 30 year old amalgam. Its not that dentists fault you needed a root canal, your 10 year absence from proper dental care, based on prevention is the root cause. Your negative comments on dentistry were surprising to me, and it would seem that you simply have not met a dentist competent to care for you, should you be cooperative, and follow their advice. Completely missed was Vitamin D3, and vitamin K2, which are instrumental in the craniofacial growth and development of the human animal. Failure to mention those critical chemical elements is shameful, though not surprising. I respect so much of what you do, but your limited investigation into the scientifically verifiable world of “alternative medicine” is disappointing to me as a fellow healthcare provider, and a victim of the incompetence of the allopathic system in both Canada and the US.
    Call me, I can give you a totally different perspective on not just dental health, but organic common sense healthcare. You don’t have to agree with me, though thousands of peer reviewed studies support what I say, but I would love to share my findings with you.

  13. Prof. Wolfgang Hartung, MD, Rheumatologist

    Dear Peter foremost congratulations to you and your team for your outstanding podcast which I already follow now for one year. I learned a lot and enjoy every new podcast. Nevertheless I have to confirm Dr. Goulds comments. The Western diet with high amount of all kinds of sugars and flour is the profound problem to tooth health. Nevertheless oral hygiene is important. Concerning systemic disease and bacterial colonization there is upcoming evidence that there’s a link between rheumatic diseases and dental health. So dental health is paramount for everyone.


  14. Dr. Attia,

    Unfortunate to hear about your poor dental experience after an amalgam restoration was replaced with a resin restoration. The pulp can be inflamed anytime a tooth is worked on, especially if that previous amalgam was a deep / large restoration.

    Amalgam restorations are not perfect (the same with white resin restorations). I find that much of the cynicism directed towards amalgam has an insidious financial motivation. If a dentist’s approach is that all amalgam restorations crack teeth and they need replaced with a white filling / crown – that creates some hard to ignore incentives. Indeed, the most dangerous part of amalgam restorations is the actual removal of the restoration. The following link is a well cited article dispelling many of the the misconceptions and half-truths regarding this time and clinically proven material.


    I will also second that having James Nestor on as a guest would be a great conversation exploring mouth breathing and its relation to dental and systemic issues. My mentor Dr. Frank Seaman is also engaged in this space – he would also be very insightful.

    Keep up the great content

    David Pelster, DDS

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