Wear a 2 unit nesbit. will abutted teeth move out of position when near future involves gum grafting of an abutted tooth (cannot wear nesbit)?

Nesbit: It is certainly possible for your teeth to shift when you do not wear this device. Will you be doing an implant to replace your missing tooth? Replacing your tooth would be better than wearing a nesbit.

Missing teeth: Without something to hold the other teeth in position, there is that possibility or your other teeth shifting. How likely depends upon many factors such as your occlusion (bite), tooth support, habits, and mostly length of time without teeth. Your own dentist can best evaluate and advise you what to do, along with risks. Why do you ask us? Don't you trust your own dentist?

Throw it out: Nesbits are no longer consisted an acceptable dental treatment. It is too easy to swallow them. (and it's no fun getting them back out) there are many acceptable alternatives. While implants are generally the best answer there are many more affordable removable designs much more favorable than a life threatening nesbit.