Snaggle-toothed hockey players and sugar lovers may soon rejoice as Canadian scientists said they have created the first device able to re-grow teeth and bones.
The above is a direct quote from the article being discussed, which is what I was responding to. You may want to RTFA more closely yourself... do you really think all this discussion and excitement would have been generated solely from an engineer making a gadget small enough to fit in someone's mouth? I think you missed the point of the article. Also, the gadget was scaled down to fit inside a person's MOUTH, not inside a tooth. RTFA.
The only dentist mentioned, Dr. El-Bialy, did not "invent" the concept of using ultra-sonic technology in dentistry; it's been used for many more years than since the '90's. He does appear to have used it in a different way and to treat a different problem than before, which is highly commendable (search for his abstract on PubMed). BUT he used it in the 1990's to treat root resorption that occurred after orthodontic treatment, NOT to completely regrow a brand new tooth. My point was that Chen, who is an engineer, is the one saying that this technology can be used to regrow a whole tooth. That hasn't been shown yet. The article does not say that the dentist backs up that statement. In my OPINION, Chen is getting a little too excited about ultrasonic technology and his scaled-down gadget. My guess is that he doesn't know a whole lot about dentistry and what is needed in order for teeth to grow. As I said before.
Tooth enamel is worn down all the time by your teeth being used, both from abrasion and acidity; this is the normal way they are supposed to work. It is continually replaced by your body, through a chemical process based around your saliva that deposits minerals on the teeth from the outside.
Well, you're right about teeth continually being worn down by abrasion... also erosion, attrition, and abfraction, all slightly different things. But ENAMEL is not continually replaced by your body, or replaced at all. It can be strengthened by SOME of the minerals you mentioned, the most important being fluoride (not calcium... calcium doesn't make a hamster's rear end of a difference to the tooth after it is fully formed... common misconception). Re-mineralization of the enamel matrix can occur after an onslaught of acidity such as after drinking an acidic soda or juice, and it can even occur in what dentists call "insipient" or very small carious lesions (cavities). But once the cavity, or bacteria, reach the dentin, which is the middle layer of the tooth, the enamel is gone and can't be replaced at that point. THAT is when the dentist has to go in and "drill"... what dentists delicately call "preparing" a tooth for a restorative filling. He or she "drills" out the soft, bacteria-infested portion of the tooth and replaces it with one of several restorative materials.
The problem is when the tooth is damaged below the level of the enamel; this can't be regrown currently (and prevents the tooth from re-enameling over the top) because the damage from eating progresses faster than the tooth can heal.
Here, you're getting enamel and dentin mixed up. Dentin is the middle layer of the tooth, located between the inner pulp (nerve tissue) and the outer relatively thin enamel. DENTIN is continually deposited throughout our lives, not enamel. So long as the tooth remains relatively healthy, odontoblasts reside within the dentin; odontoblasts are the cells responsible for continually depositing dentin. The dentin layed down while the tooth is initially forming is called primary dentin. Dentin layed down after the tooth has fully developed is called secondary dentin, and the deposition of secondary dentin increases especially after the age of 35 or 40. This is why dentists may have a harder time finding the pulp tissue within a tooth for a root canal procedure as people age. Here's the important part: Dentin layed down in response to trauma, such as a bacterial insult (cavity) is called tertiary or reparative dentin. As long as the "nerve" of the tooth does not die (become necrotic), the odontoblasts can still do their job, but tertiary dentin is much harder and more disorganized than the other two types. But again, once enamel is gone, it's gone. If the matrix is still there, there's a chance it can be remineralized, which is why dentists hound everyone to brush and floss and also why we drown you in fluoride everytime you come in for a hygiene appointment.
One other thing; don't get tooth wear mixed up with tooth structure lost due to bacteria. You are right in that teeth continually wear down during our lifetimes; but that is where secondary dentin comes in, and also cementum, which is present on the surface of the root of the tooth. As we age, teeth continue to do what's called "passive eruption" to make up for normal tooth wear occurring over a lifetime. Teeth have no such weapons to combat structure loss due to bacteria. Although, there has been significant research done to come up with a vaccine against the bacteria that commonly cause caries, or tooth decay.
There is also a great sugar out there called Xylitol... it is a sugar, but the bacteria that cause caries cannot live off of it. Chewing gum containing Xylitol actually has caries-resistent properties. Gum chewers, rejoice!
Horse hockey on the "growing a new tooth" thing, but I can see repairing damaged teeth, depending on the cause of the damage. You need the presence of odontoblasts, etc in order for a new tooth to grow. That guy Chen is an engineer, not a dentist. I'm thinking he doesn't really understand how teeth form and grow, so he's got high hopes for his invention. The root structure of teeth is covered in cementum and dentin, which are repairable, so it makes sense that teeth with root resorption may be fixed by the ultrasonic thing. But to completely grow new teeth, you'd have to have "tooth stem cells" in the area, and those stem cells would have to know what size and shape of tooth to form for that area. I don't see that one happening. I also don't see damaged enamel being fixed by this thing; once enamel is gone, it's pretty much gone.
Slashdot Mirror
Snaggle-toothed hockey players and sugar lovers may soon rejoice as Canadian scientists said they have created the first device able to re-grow teeth and bones.
The above is a direct quote from the article being discussed, which is what I was responding to. You may want to RTFA more closely yourself... do you really think all this discussion and excitement would have been generated solely from an engineer making a gadget small enough to fit in someone's mouth? I think you missed the point of the article. Also, the gadget was scaled down to fit inside a person's MOUTH, not inside a tooth. RTFA.
The only dentist mentioned, Dr. El-Bialy, did not "invent" the concept of using ultra-sonic technology in dentistry; it's been used for many more years than since the '90's. He does appear to have used it in a different way and to treat a different problem than before, which is highly commendable (search for his abstract on PubMed). BUT he used it in the 1990's to treat root resorption that occurred after orthodontic treatment, NOT to completely regrow a brand new tooth. My point was that Chen, who is an engineer, is the one saying that this technology can be used to regrow a whole tooth. That hasn't been shown yet. The article does not say that the dentist backs up that statement. In my OPINION, Chen is getting a little too excited about ultrasonic technology and his scaled-down gadget. My guess is that he doesn't know a whole lot about dentistry and what is needed in order for teeth to grow. As I said before.
Tooth enamel is worn down all the time by your teeth being used, both from abrasion and acidity; this is the normal way they are supposed to work. It is continually replaced by your body, through a chemical process based around your saliva that deposits minerals on the teeth from the outside.
Well, you're right about teeth continually being worn down by abrasion... also erosion, attrition, and abfraction, all slightly different things. But ENAMEL is not continually replaced by your body, or replaced at all. It can be strengthened by SOME of the minerals you mentioned, the most important being fluoride (not calcium... calcium doesn't make a hamster's rear end of a difference to the tooth after it is fully formed... common misconception). Re-mineralization of the enamel matrix can occur after an onslaught of acidity such as after drinking an acidic soda or juice, and it can even occur in what dentists call "insipient" or very small carious lesions (cavities). But once the cavity, or bacteria, reach the dentin, which is the middle layer of the tooth, the enamel is gone and can't be replaced at that point. THAT is when the dentist has to go in and "drill"... what dentists delicately call "preparing" a tooth for a restorative filling. He or she "drills" out the soft, bacteria-infested portion of the tooth and replaces it with one of several restorative materials.
The problem is when the tooth is damaged below the level of the enamel; this can't be regrown currently (and prevents the tooth from re-enameling over the top) because the damage from eating progresses faster than the tooth can heal.
Here, you're getting enamel and dentin mixed up. Dentin is the middle layer of the tooth, located between the inner pulp (nerve tissue) and the outer relatively thin enamel. DENTIN is continually deposited throughout our lives, not enamel. So long as the tooth remains relatively healthy, odontoblasts reside within the dentin; odontoblasts are the cells responsible for continually depositing dentin. The dentin layed down while the tooth is initially forming is called primary dentin. Dentin layed down after the tooth has fully developed is called secondary dentin, and the deposition of secondary dentin increases especially after the age of 35 or 40. This is why dentists may have a harder time finding the pulp tissue within a tooth for a root canal procedure as people age. Here's the important part: Dentin layed down in response to trauma, such as a bacterial insult (cavity) is called tertiary or reparative dentin. As long as the "nerve" of the tooth does not die (become necrotic), the odontoblasts can still do their job, but tertiary dentin is much harder and more disorganized than the other two types. But again, once enamel is gone, it's gone. If the matrix is still there, there's a chance it can be remineralized, which is why dentists hound everyone to brush and floss and also why we drown you in fluoride everytime you come in for a hygiene appointment.
One other thing; don't get tooth wear mixed up with tooth structure lost due to bacteria. You are right in that teeth continually wear down during our lifetimes; but that is where secondary dentin comes in, and also cementum, which is present on the surface of the root of the tooth. As we age, teeth continue to do what's called "passive eruption" to make up for normal tooth wear occurring over a lifetime. Teeth have no such weapons to combat structure loss due to bacteria. Although, there has been significant research done to come up with a vaccine against the bacteria that commonly cause caries, or tooth decay.
There is also a great sugar out there called Xylitol... it is a sugar, but the bacteria that cause caries cannot live off of it. Chewing gum containing Xylitol actually has caries-resistent properties. Gum chewers, rejoice!
Horse hockey on the "growing a new tooth" thing, but I can see repairing damaged teeth, depending on the cause of the damage. You need the presence of odontoblasts, etc in order for a new tooth to grow. That guy Chen is an engineer, not a dentist. I'm thinking he doesn't really understand how teeth form and grow, so he's got high hopes for his invention. The root structure of teeth is covered in cementum and dentin, which are repairable, so it makes sense that teeth with root resorption may be fixed by the ultrasonic thing. But to completely grow new teeth, you'd have to have "tooth stem cells" in the area, and those stem cells would have to know what size and shape of tooth to form for that area. I don't see that one happening. I also don't see damaged enamel being fixed by this thing; once enamel is gone, it's pretty much gone.
... Kinda like the titanic, huh?