I do believe that Aleksei's teeth had a gap either on the top row or bottom row, heres a link to a thread of him smiling:
http://hydrogen.pallasweb.com/cgi-bin/yabb/YaBB.cgi?board=alexei;action=display;num=1123191758And in a pic of him with his father in a rowboat, you can see that when he had baby teeth, he DID in fact have a gap in between his 2 front teeth in the upper row.
Like Stacey said (I agreed wholly with every single thing that she wrote), it could be that that was only his baby teeth.
I know this, because I wear braces, but I had PERFECT baby teeth, though, in Aleksei's case it is vice versa. Â

Though, in a photo of him standing in front of one of his relatives, smiling, the one that Stacey was describing, he is older and STILL has a gap in the same area of his teeth as I mentioned before.
To look at this, genetically, it would seem very likely that all OTMAA, including Aleksei, had bad teeth. Nicky, obviously had bad teeth, I do not know if they were like that naturally, or because of his habits of smoking and not frequenting the Dentist's office enough.
Though, since Alix DID have much work on her teeth, a known fact as they found evidence of this in the grave where the Romanov bodies lay, OTMAA may have inherited her poor teeth.
To further back my thoughts, there is a photo of Aleksei at Stavka, with all his front mature teeth in place, where, though it is dark, if you brighten it, or look closely, you can see a gap between his two front teeth.
Two of the photos that I mentioned were posted by Abby, so the other, you can find for yourself in the link that I provided, hopefully! EDIT: It is the first pic in the the thread that I provided, it is posted by Baby_Tsarevich.
Sofi
