What you are doing is okay and having one single tooth sticking way past the other automatically makes it more prone to breaking as it lacks the support of the other tooth.
I do know that continuously giving hard shelled large nuts - hickories, black and even english walnuts that have the squirrel spending hours gnawing with their mouths open so far is as much a possible contributor to odontoma as cage bar chewing is. Cracking the big hard ones for your little pipsqueaks is a good idea. So are the Teklads. My gray actually likes them and when you hear them chewing them you will recognize how much nice, controlled, gentle grinding they are doing when they are eating them (great sound - like fingernails on a blackboard)!
I knew that those plus all the lumber and furniture
he chews was keeping his teeth looking just fine, and NOT giving whole nuts let me give him so many MORE nuts (he thinks) by cutting the shelled ones into multiple pieces. He very much looks forward to his "nut hunt" every night.
Their top incisors float in the jaw and will spread apart - looking at the squirrel from the front they look like an upside down V - which anchors the nut like prongs so the bottom teeth can scrape a hole in the shell that they can then use to lever the shell open. The top teeth - the ones that tend to develop odontomas - are meant to move from side to side. NOT front to back, which is what cage bar chewing (they hook their teeth over the bars and pull backward) and trying to break into a hard shelled nut is doing - putting pressure on the teeth from a direction they are not designed to function. Over time, I very strongly think those two things, if never made possible for the squirrel, would make a difference in the incidence of odontoma in squirrels that did NOT suffer facial trauma in their fall from the nest as babies. That is just my personal opinion, and I am certainly not a vet or dentist (though I do have one that I give huge amounts of $$ to). But forcing parts of your anatomy to function in ways they are not built for just seldom ends well.