Topics of the day:

1. Re: Impacted teeth
2. Re: Impacted teeth
3. Effects of force application on the root formation of impacted teeth
4. Exact specifications for Arnett Facial Analysis
5. Correction to expiration date of Arnett patent
6. ESCO - The Electronic Study Club for Orthodontics

Dear John,

From:  JMer1997@aol.com
Date:  Sun, 6 Jun 2004 01:58:32 EDT             
Subject:  Impacted teeth             
To:  ESCO@LISTSERV.UIC.EDU

      I have recently been discussing a case with my oral surgeon involving when impacted teeth (canines in this case) can have attachment and force placed upon them.  I was taught that if a tooth were moved before root formation was complete there was a good chance that root development would stop and you would end up with a short blunted root.  He seems to think that if you don't pull to hard, you can attach them at anytime.
      I did a medline search and had the AAO library do a search and I could not find an article that dealt with what happens if teeth are      
moved with only 1/2 root development, or 3/4 development.  All of the articles assumed full root development and dealt mostly with      
creating space and clever ways to bring teeth into the arch. Nothing on when to attach and what happens if you attach and pull before complete root formation,
      Now for the questions for the group:
1)  Does anyone know of any articles dealing with this subject? I especially would like some case reports on what happens when a tooth is attached and moved with 1/2 or less root development. 

I don't know of articles offhand and don't recall articles on this as such. However, Joho speaks and I think may be published (think Zachrisson as well) on transplants where development of further length ceases after transplantation. In the very few transplants I have done, this seems to be the case.
Perhaps the surgeon is thinking of transplant rather than exposure.

      2)  Any anecdotal stories out there from the combined million or so years of clinical practice this study club taps into?

My hunch is that root development continues BUT the root form is modified and bends and twists, reflecting the history of tooth movement while both the root is being formed and moved, can occur which would make later RCTs (root therapies not randomised clinical trials) very difficult.
I would be surprised if root growth ceased. Take for example where E's have a cyst and the region is treated and the 5 erupts after its development was delayed, I have seen good root growth and rapid eruption.
BTW, for me, normally a lot of root growth would be present before I would request exposure.

      I await any and all replies.
      John McDonald Orthodontist Salem, Oregon
      PS  The Library service that the AAO provides is really great.You give them a subject or a question and they will send you a lot of      
articles.  All it takes is a phone call.  It is a nice resource to have.

Regards, Mark Cordato markc@ix.net.au Bathurst Australia

Dear John

Here is what I found regarding your question:

Changes in Root Length During Orthodontic Treatment: Advantages for Immature Teeth.

Mavragani M, Boe OE, et al:

Eur J Orthod 2002; 24 (February): 91-97

I do not know if you can call this evidence, but it might well be that our reluctance to move immature teeth is based on a preconception too.

Kind regards

Marco Tribo

Dear John McDonald,

Material published on this topic seems to be limited. I came across an interesting article on this topic in  the World Journal of Orthodontics, W.J.O.2003,4:13-18. Hope this would be of help to you. I have treated a few cases and I seem to be in agreement with the conclusions of this article.

Mandeep Sood, Toronto, Canada.

The most precise and complete description of Arnett's facial analysis is his own description in his patent on the method: US Patent No. 5,951,498 file August 3, 1998, issued Sept 14, 1999. You can see it at the following link. If that doesn't work, go to the US Patent & Trademark Office (USPTO) web site and do a search for that patent number. (Some mail-reading programs cut long URL names like this into pieces, which don't work.)

http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/search-bool.html&r=3&f=G&l=50&co1=AND&d=ptxt&s1=Arnett.INZZ.&s2=facial&OS=IN/Arnett+AND+facial&RS=IN/Arnett+AND+facial

Because it is patented, by law anyone "practicing" the patent, i.e., using it, must have the authorization of the patent owner, which may involve paying royalties. I suggest that you write to Arnett himself for approval. The patent gives the inventor a monopoly on practicing the patent in the US for 20 years from the date of application for the patent. Therefore, to use his analysis without his permission, you'll have to wait until August 3, 2018! Of course, if you infringe on his patent by using it without permission, he'd have to find out about it and sue you in US federal court, which is unlikely unless you're making a business out of it. There's no "fair use" doctrine in patents, as there is under copyright law.

Over the last 20 years, the USPTO has been granting patents on software ideas and business methods, which has been an onerous development. It inhibits the advancement of the art and science rather than encouraging it. A lot of bad patents have been issued that should not have been. The European patent office is in the throws of a political battle over doing the same thing in Europe. Big money is being thrown at the political issue there. In the US, some organizations are trying to do something about it, but it's a bit like trying to get the toothpaste back into the tube. For an eye-opening account of this whole affair, go to http://www.chillingeffects.org .

Stan Sokolow

Just to set the record straight, I notice that Arnett claimed the filing date of his provisional patent application, so his patent's 20 year life began to run on Oct 16, 1997, and thus the patent expires Oct 16, 2017.

Stan Sokolow

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