Metal Mouth Message Board

Just curious. I know that it's not advisable to put heavy archwires on the teeth to quickly and that the progression in archwires must be slow because otherwise it might result in root resorption, but I would like to understand exactly what happens in the teeth/roots and how.
I am betting that Meryaten, with all her knowledge, will jump in with the answer... Or maybe others ? Perhaps Dr Rick ?
Thanks in advance for those who can enlight me on this.

I found this on pubmed. Seems to say that there is a very fine line between bone remodelling and root resorption:

Orthodontically induced root resorption is the most frequent unwanted side effect of orthodontic tooth movement that is unavoidable. This is due to the fact that both bone remodelling and root resorption are based upon a sterile inflammatory process, initiated by force application. In addition to individual factors that have a bearing on the amount of resorption, the type and magnitude of orthodontic forces play a major role. In animal and human experiments it could be shown that continuous forces, as produced by materials with pseudo- elastic characteristics, seem to produce more resorptions than discontinuous forces. Recent research shows that the magnitude of the orthodontic force up to 200cN is probably not decisive for root resorption
Weiland F.
Dept. of Orthodontics, Graz Dental School, Austria.

Wow Maryaten, that's some awesome research!

There's a lot of information in that link you posted, I love the science of orthodontics so I'll enjoy reading some of it!

I also agree with you in that I would love to hear from Dr Rick or Rory about this as well.

jennielee81 and Meryaten, thanks ! Your information is very helpful !
I too love reading that kind of stuff ! Not only do I learn new stuff, but it also and mainly helps me be patient as I understand WHY the orthodontic process is AND MUST BE SLOW. As much as we may lament about it, it is the truth and we must come to terms with it (at least I do).

Now I agree it would be great to hear Rory or Dr Rick on this subject.

There are two main types of root resorption, internal and external. Internal resorption happens from the inside out. Radiographically it will look like the canal is getting larger and the walls are getting thinner. External root resorption works in the opposite manner, from the outside in. External is the most common potential resorption from orthodontics and comes from applying too much force. Without going in to too much detail, orthodontic movement involves the breakdown and remodeling of the PDL and associated attachment apparatus of the tooth. It is a normal process and involves normal "wound healing" processes (ie - increased blood flow and associated inflammatory responses). If too much force is used the inflammatory response becomes too much and the body attacks the tooth. This is one of the reasons why orthodontics uses light forces and it takes so long. This is also why if a tooth is involved in a traumatic event, it often times recieves Root Canal Therapy to prevent internal resorption. So when your dentist schedules you for follow up appointments if you are exposed to trauma don't be upset

Best,
Rory

Thanks Rory, this makes perfect sense.

Wow...this makes me re-think my pleasure at having pain after adjustments in order to think movement is happening

I just had my braces tightened 2 weeks ago. (2/14) On or around 2/19 I started getting extreme sensitivity with one tooth up front (where I had power chains added), then on Friday 2/25 I noticed my tooth is becoming discolored with a light brownish/reddish color up at the very top of the tooth. I'm going to the dentist in a week, but I'm really worried. Has anyone ever had this happen? I'm worried it's resorption, and that I'll need a root canal or worse.

If you do a search for rr in my name I made a lengthy post about it a little while back.