it is interesting
They are actually doing studies as they speak to try and answer this question
Its called the twin tooth emergence study
Twins are followed as they teeth come through to try whether there is a link in the order your teeth come through and genetics!
They have recruited 100's of sets of fraternal and ID twins around Australia. They offer a free DNA test to confirm whether they are in fact ID or not- and quite a few friends have had surprises to find that their twins are actually ID when they thought that they were in fact fraternal!!!!

My twin friends and i, both ID and fraternal have found that they tend to come through around the same time, but not at the same time usually - If that makes sense.
Usually onr twin would get a tooth through and as soon as they got over that one, the other twins would get one through! So it would be constantly someone teething- such fun!

If you are interested in their research further, jump on the AMBA web site for links to this research and other interesting things they are finding out by using twins for reseach purposes!
HTH
odette