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Radio Transcription
Ep 57: Part 3 of 3 of Dr. Chao's Interview with Dr. Yang Chai; Tissue Regeneration; How Dr. Chai was trained in China, Repairing Facial Defects; USC Research
Salvador Gaytan: It's time ladies and gentlemen! SmileTalk is on the air, featuring the latest news and developments in dental health, as well as other fascinating topics that make people smile. I am Salvador Gaytan, and I'm here with…?
Dr. John Chao: Dr. John Chao, hi everybody. I'm glad you can join us. We'll have a really exciting program for you. Stay tuned.
Salvador Gaytan: Absolutely. And we have been graced with Dr. Yang Chai, the Associate Dean of Research of the Herman Ostrow School of Dentistry at USC, and the Director of the Center of Craniofacial Molecular Biology. We got him to come back for one last third show, because we still have some fascinating topics to talk about, don't we, Dr. John?
Dr. John Chao: Yes, and well, I was particularly interested in how he was trained at the Peking University, and how advanced his training was in terms of cleft palate research and surgery there, and then he brought it to the United States.
Salvador Gaytan: Yes, and there's a very interesting connection that you two have.
Dr. John Chao: Well, actually I went to China with a group of dentists and one physician in 1973 and we were given tours of different dental hospitals and training facilities there, and one of the most impressive things I learned there was their dentists did a lot of craniofacial surgery, not only cleft palate, but they treated burn victims and did reconstructive surgery for facial defects and so on, and did cancer surgery.
One of the things I observed was that -- and I still have a picture of it, is this little girl whose face was burnt, and she was getting treated with skin made into a blood vessel. It's a large tube, it connected her wrist, the blood supply from the wrist to the face.
And this always stayed with me, how advanced the surgical techniques were even back in the 70s, and we didn't see anything like that in the United States, until much, much later I understand. Now, I understand Dr. Chai that you have some knowledge of that particular procedure, and it's called a…
Dr. Yang Chai: Forearm flap.
Dr. John Chao: A forearm flap, there's actually a name for it.
Dr. Yang Chai: Yes.
Dr. John Chao: Now, who developed that in China?
Dr. Yang Chai: Yeah, thank you for having me on your show.
Dr. John Chao: Our pleasure.
Dr. Yang Chai: It's really a pleasure to come back. So, I have to give you a little bit of background about how we were trained in China to become a dentist. So, in China, unlike in United States, you basically go through medical school first.
You have to learn how to become a physician and then you specialize in dentistry, we call it stomatology. So, within the dental school, there is the oral maxillofacial surgery department, where you visited in China, and in that department we have different specialties.
We have head and neck cancer group, we also have plastic reconstructive surgery group. We also have a head and neck trauma group.
Dr. John Chao: So, these people were trained as physicians first, and then they specialized in dentistry just like the other specialties, and within dentistry then there were different departments.
Dr. Yang Chai: Right. So, in the oral maxillofacial surgery department, where patients would get treatment for many of these areas that normally would be treated by physicians in the U.S., and the particular procedure you observed back in the early 70s was actually this reconstructive procedure.
It was invented by my former mentor, Dr. Guanghe Wang. Her invention was to use the skin flap along with the artery and vein in your forearm to repair defect in the facial region.
Dr. John Chao: How did she get the skin? Was it from the forearm also?
Dr. Yang Chai: Yes. So, the skin and also the blood vessels are all basically removed from the forearm, and then are connected with the facial artery and vein, and then the skin is used to repair the defect.
Dr. John Chao: So, actually she dissected the artery from the forearm, and then connected it to the burnt face?
Dr. Yang Chai: Right, and so connected -- so, that involved some microvascular surgery to connect the blood vessels, and also to use the skin flap to repair the soft tissue.
Dr. John Chao: So, taking the artery from the forearm didn't damage the forearm?
Dr. Yang Chai: Because there are multiple artery supplies.
Dr. John Chao: Yeah, I see. There's collateral circulation there. So, there are other arteries that would take care of the forearm.
Dr. Yang Chai: Right.
Dr. John Chao: So, that was not essential to the forearm.
Dr. Yang Chai: Right, and you are -- basically there is limitation about how big the forearm flap can be. So, her contribution was not only to think about using that as a resource for the facial repair, but also to define the size and the technical aspect on how to use that flap to repair the defect.
Dr. John Chao: Now, in your training, did you see that being done at your hospital?
Dr. Yang Chai: Yeah, multiple times. Actually that was part of our surgical training in the residency program, yeah.
Dr. John Chao: Wow. And did you see good results with that, because the patient I saw looked really good.
Dr. Yang Chai: Yeah, very. I mean when patients have tongue cancer, they have part of the tongue removed, and then along with the cheek and the facial structures. So, it would be very difficult for you to use local resources to repair that defect, and you can get a flap from your chest or you can get this forearm flap, which has a very good blood supply, and then the blood vessel can also be easily connected with the facial arteries and vein, so that the result is very good.
Salvador Gaytan: So, that technique originated in China?
Dr. Yang Chai: Yes, and actually it was widely used throughout the world, and the technique is still being used today.
Dr. John Chao: Because that's not something that requires a tremendous amount of high tech equipment. That's basically surgical skill, isn't it?
Dr. Yang Chai: Right, it's a lot of training.
Dr. John Chao: A lot of training, but a person can be trained for that, and they can go to anywhere in the world and perform that particular procedure…
Dr. Yang Chai: Yeah, be able to perform a surgery.
Dr. John Chao: Without a whole bunch of highly sophisticated machinery.
Dr. Yang Chai: Right. And as you know, also there were some other pioneering surgeries in China, such as connecting a severed arm or a hand that was done in the early 70s or DELETE late 60s or early 70s.
Dr. John Chao: Really? And that then became popularized in other parts of the world. So, it originated in China.
Dr. Yang Chai: Yeah.
Dr. John Chao: Wow. That's terrific.
Salvador Gaytan: And for anyone just tuning in, you're listening to SmileTalk with Dr. John Chao, spelled C-H-A-O. You can reach Dr. John Chao at AlhambraDental.com or Chao Radio -- do I have that right?
Dr. John Chao: Dot com. C-H-A-O Radio.
Salvador Gaytan: C-H-A-O, ChaoRadio.com, that's the new one, or 626-308-9104, and right now we have our special guest, Dr. Yang Chai, the Associate Dean of Research at the Herman Ostrow School of Dentistry at USC, and also the Director of Craniofacial Molecular Biology.
Dr. John Chao: And we were talking about flap.
Salvador Gaytan: Forearm flap.
Dr. John Chao: Forearm flap. You connect the arteries from the forearm -- one artery from the forearm, and connect it to a burnt part of your body, to regenerate that part. And this started in China, as well as some of the other surgery that can actually reattach different parts of the body, and that started in China, as well as many other things that started in China.
Salvador Gaytan: Now, I have a question there for Dr. Chai. Have you performed forearm flaps?
Dr. Yang Chai: I assisted when I was a resident, yeah.
Dr. John Chao: How fascinating. What other things were originated from China?
Salvador Gaytan: The toothbrush.
Dr. John Chao: Toothbrush, the magnet.
Salvador Gaytan: The magnet, really?
Dr. John Chao: Gunpowder.
Dr. Yang Chai: And paper.
Dr. John Chao: Paper. How about printing? Was printing part of it?
Dr. Yang Chai: Printing, yeah.
Dr. John Chao: Printing, part of it.
Salvador Gaytan: Wow.
Dr. John Chao: And the chopstick.
Salvador Gaytan: The chopstick too?
Dr. John Chao: Yeah. [Laughter]
Salvador Gaytan: Wow, that's crazy. I didn't know that.
Dr. John Chao: Yeah, I'm as stiff as a chopstick. I'm going to be taking yoga lately, so I tell my instructors I'm like a chopstick.
Salvador Gaytan: You've been taking yoga?
Dr. John Chao: Yeah.
Salvador Gaytan: I didn't know that.
Dr. John Chao: I've been taking Bikram Yoga. Bikram Yoga is hot yoga. You go into a sauna room, where it's 104 degrees, and then you do all the twisting and turning in there. So, I stick out like a chopstick. I told my instructor, don't be surprised, I'm like a chopstick.
Salvador Gaytan: Don't be surprised.
Dr. John Chao: Yeah. But afterwards, I feel like a soft noodle.
Salvador Gaytan: Soft noodle. Well, actually now that you mention it Dr. John, you swim also.
Dr. John Chao: I used to swim.
Salvador Gaytan: Used to, you're not swimming now?
Dr. John Chao: Well, after you do an hour and a half of Bikram Yoga, you don't feel like doing anything, you just want to relax.
Dr. Yang Chai: Or you stay outside in a hot summer day, that's a natural sauna for you.
Dr. John Chao: That's right. It started in Calcutta when the yogis were doing yoga in 110 degrees, and it was very hot. So, this gentleman yogi brought it over. Now, I'm not recommending it for anybody. Let's be clear about that. You have to get your physician's okay for that kind of thing, but it was okay with me.
Dr. Yang Chai: You have to have proper instructions.
Dr. John Chao: Yeah, proper instructions. You can't just go into a sauna and start twisting. It's kind of like a class, everybody does it together.
Salvador Gaytan: Now, Dr. Chai, how long do you swim when you swim?
Dr. Yang Chai: Half an hour usually, yeah. A lot of my research ideas come to me when I'm swimming.
Dr. John Chao: Oh really, yeah?
Dr. Yang Chai: It's a very relaxing time, but also I feel my head is really clearer when I'm swimming.
Salvador Gaytan: Interesting.
Dr. John Chao: Yeah, I can see that.
Salvador Gaytan: That is fantastic. Now, we're talking about our final topic, which is dealing with Dr. Chai's surgical training. And would you term it artificial or actually bio-mineral regeneration?
Dr. Yang Chai: Yeah. So, part of our center's research focuses on regenerating enamel. So, as we -- our research unit in the dental school were very much interested in how we can improve the restoration of natural dentition.
Dr. John Chao: So, we're really talking for the general public. We're talking about a cavity that's right now being filled with amalgam, a silver filling material, or we use a composite, which is a plastic glass material that's put into the cavity after the cavity is cleaned out.
So, now we're talking about putting a piece of real living organic enamel, which is the outside part of the tooth, and having that fill the cavity. So, when it's all filled, it's like the natural tooth is back. Is that what we're looking at?
Dr. Yang Chai: Right. So, we have several faculty members at our school who are really pioneers in this area of research; Dr. Malcolm Snead, who actually is the first one that cloned the gene that's responsible for making the enamel, one of the important genes for making enamel.
Dr. John Chao: Well, that's astounding research, and that came out of USC.
Dr. Yang Chai: Yeah. In the early 80s, it was more than 20 years ago. And also, we have Dr. Michael Paine and Janet Oldak; all of them are focusing their work on how we can control the cells in the outside environment, to be able to use these cells to generate artificial enamel with the right type of a crystal structure. So, then we can form the size and the shape, and the amount or quantity we desire, and then use that to repair any dental defect.
Dr. John Chao: So, you actually use some kind of a genetic material? You use something that can form enamel?
Dr. Yang Chai: So, you take cells that can be reprogrammed to form enamel.
Dr. John Chao: These cells are from humans or are they just…?
Dr. Yang Chai: Or from animal models, yeah.
Dr. John Chao: Which is -- and make them like human enamel?
Dr. Yang Chai: Like the cells that are responsible for making enamel, are called Ameloblast. These are cells that are there before you even get the first layer of enamel.
Dr. John Chao: Regardless of what species it is?
Dr. Yang Chai: Yeah. So, there's basically any animal that has or humans that have enamel on the surface of their tooth, they have to have Ameloblast cells to form the enamel.
Dr. John Chao: Okay. So, enamel is the same whether it's in a dog or a monkey or a man?
Dr. Yang Chai: Structurally there are some differences in terms of thickness and the structures, but that enamel is the hardest tissue in our body, and the reason it is hard, is because not only the cells are there to lay out the matrix, but also they form these crystals, special crystals, that gives them the unique property to be very hard.
Dr. John Chao: Yeah. So, we understand that you cannot transfer, let's say, something from an animal to the human being, because of species difference. But in terms of the enamel itself, that doesn't generate a rejection, foreign body reaction type of situation in the human being, when the enamel is actually derived from an animal?
Dr. Yang Chai: So, in our teeth, the enamel has very little organic material, or it's basically all inorganic. So, the possibility of rejecting an enamel material is very minimal.
Dr. John Chao: So, you grow the enamel with cells from an animal of some kind, or even a human being?
Dr. Yang Chai: From a human being, yeah.
Dr. John Chao: Okay. And then how do you direct these cells to grow -- how do you grow enough enamel there?
Dr. Yang Chai: So, what these researchers are doing in the laboratory is to learn how natural teeth make their enamel during tooth development. And then we basically learn how the genes are controlled, how the cells secrete materials to eventually form enamel.
Then, we activate this process using the cells that we have programmed to form enamel, and then basically just go through the same exercise as the tooth is developing and forming enamel.
Dr. John Chao: So, now you mentioned something about using a virus to put a gene into a cell to do this.
Dr. Yang Chai: So, there are many ways that you can reprogram a cell to become a different cell type. So, if you take a cell from your skin, that you look at under the microscope, and then you know there are certain molecules in the cell that will identify that cell as part of the skin cell.
But in order for you to reprogram that cell to become, let's say, a muscle cell in the future, so you need to manipulate this genetic component. So, how do you get the gene into a cell to reprogram it into becoming another cell type? You can use a virus, an inactivated virus, meaning that's not going to cause any harm, but using that virus as a vehicle to bring a genetic material into that cell.
Dr. John Chao: So, the virus can get into the cell that you want, carrying the gene that you want.
Dr. Yang Chai: Right, because a virus has the ability to infect a cell. That's how when we get infected by a virus, and then that can cause harm, is simply because a virus has the ability to penetrate a cell.
Dr. John Chao: So, that's like what you mentioned the Trojan Horse effect.
Dr. Yang Chai: Exactly.
Dr. John Chao: You take a virus as the conveyer of a gene, and get it into the cell, so that the cell would do what you want the cell to do.
Dr. Yang Chai: Right. So, the virus is not really causing any harm, but it's used as a delivery vehicle to target a particular gene delivery.
Dr. John Chao: And that's one of the ways you can use to get cells to do what you want to do. And then that also could be used as a means to generate more enamel, which is what we're talking about.
Dr. Yang Chai: Right, yeah.
Salvador Gaytan: And for anyone tuning in, you're listening to SmileTalk with Dr. John Chao, and you can reach Dr. Chao, spelled C-H-A-O at AlhambraDental.com or ChaoRadio.com or 626-308-9104.
We're talking with our special guest, Dr. Yang Chai, from the Herman Ostrow School of Dentistry at USC, and we're talking about some fascinating things, about tissue regeneration. And there was a little bit more that you wanted to get into, wasn't there Dr. John, about the student research?
Dr. John Chao: Yes. We have been talking about how a USC research is being done to generate enamel, real enamel that can fill a cavity rather than using artificial substances. But we do want to touch upon how the programs restructured at USC involves the training of student doctors.
Dr. Yang Chai: Yeah. So, that's very important to us. We have a very extensive research program at the Herman Ostrow School of Dentistry at USC, both basic research and clinical research, and also research involving community outreach and access to care and preventive dentistry.
So, all of these areas are very important. We have people who are doing pioneer research using saliva as a diagnostic tool. So, instead of taking some blood from a patient to run a blood test, you can take some saliva, then use that to run a diagnostic test.
Also, we have patients who have the faculty members, who are looking at how certain types of viruses may cause birth defects, or how bacteria can cause cavity, and how we can prevent these bacteria from causing cavity.
Dr. John Chao: So, these are information you can get just from the saliva itself.
Dr. Yang Chai: From saliva or these are some of the other research work that our faculty are doing at our school. So, our students really have the opportunity to select from a vast array of research topics that are being carried out by our faculty, and our students will use this opportunity to learn how not only to learn from the textbook, but also learn from our faculty, who are really conducting the cutting edge research.
And so, they use this newly generated information on their patient care, so that will provide them with a very solid foundation for their future practice.
Dr. John Chao: I've seen them in competition with other schools, with their projects. And so, they apparently do experiments at the school, and then they do present it at certain functions, because I have been a judge of Table Clinics at the CDA Convention in Southern California, in Anaheim, and I've seen students not only from USC, but from other schools competing by presenting their experiments on different topics.
So, I know that USC has been very active in that particular area. That's one of the things that students do to stimulate the interest, it's to actually generate their own experiments.
Dr. Yang Chai: Absolutely. And we think it's very important for our students to have the opportunity to present their work. They actually present their research results at multiple levels. As a school, we have our Annual Research Day.
Usually that happens in February of every year, and that's a school wide event, at which time, students, faculty will come together, present their work, and then we actually learn from each other what kind of research work is going on at school.
And then through that event, we actually select students who are winners in different categories, basics research or clinical research, and then we send these students to state or national meetings where they would present their work.
But also they will enter competitions, such as at the meeting of American Association of Dental Research or International Association of Dental Research, or American Dental Association Annual Meeting or CDA, and various events that are both at the state and the national level.
Dr. John Chao: Yeah. I'm reminded of -- Sal, don't you remember, we had students from USC.
Salvador Gaytan: That's right, very fascinating.
Dr. John Chao: They presented their research on Fosamax, and how Fosamax is associated with bone death, osteonecrosis.
Dr. Yang Chai: Right, osteonecrosis.
Dr. John Chao: And their paper generated at USC was actually published in the Journal of the American Dental Association, and we had them on this show, and they talked about it -- we took a couple of sessions.
Salvador Gaytan: It was very fascinating.
Dr. John Chao: And they were very interesting young men.
Dr. Yang Chai: Yeah, and that paper now is being used by many dentists as a very important reference in terms of patient education, and also how to treat these patients.
Dr. John Chao: And the one thing came out of that interview with the students was that the FDA actually took note of it, and changed the warning, that the manufacturer had to place on their product, to warn doctors who would prescribe that particular medication, of the possibility of osteonecrosis or bone death, as a result of using it for a certain period of time, and there are certain conditions, under which they are required to actually stop using it.
Dr. Yang Chai: And now, that information is being incorporated into the new textbook. So, that's a perfect example of knowledge generated at USC, at our School of Dentistry. Then, not only our students have the opportunity to learn that first hand, but also be able to help to write the future standard for patient care.
Dr. John Chao: Yeah. And it's unique in that the students actually participated in this particular piece of research, along with the -- under the guidance, of course, of their professors, and the researchers at USC.
Salvador Gaytan: Well, we're coming to the last minute of our show, but one little item I wanted to get in is that you, Dr. Chai, you still practice one day a week, don't you?
Dr. Yang Chai: Yes, I do.
Salvador Gaytan: And you find that keeps your skills alive there and sharp?
Dr. Yang Chai: I love seeing patients. Really, I think it's one of the important parts of my professional life. My research interest stemmed from patient care, and I would like to continue to do that, and just to be able to help patients, big or small, but still I just like to keep in touch with patient care.
Dr. John Chao: Now, professors and teachers at USC, it's part of what's called faculty practices or faculty…?
Dr. Yang Chai: So, we have an intramural faculty practice, where I work at the oral health center in our school, where we see our patients, and so they come from the university and from outside, and we have just a great population of patients.
Salvador Gaytan: Well, coming to the last few seconds. We've been interviewing Dr. Yang Chai, the Associate Dean of Research of the Herman Ostrow School of Dentistry at USC, and the Director of the Craniofacial Molecular Biology. I love that title, Dr. Chai, and it's been a pleasure having you.
Dr. John Chao: Thank you very much, Dr. Chai, for coming on the shows.
Dr. Yang Chai: Thank you so much for having me, really, it's been fun.
Dr. John Chao: It's an honor and a pleasure for us.
Salvador Gaytan: And you can reach Dr. John at AlhambraDental.com or ChaoRadio.com or 626-308-9104; next week everybody.
Dr. John Chao: Thank you.
[END OF AUDIO]
