Rick,

Nesbits are not meant to be used for chewing because food can get stuck on them, pop them out and that's when you could choke on it. If swallowed, the acrylic ones are more likely to pass through the digestive tract without getting caught as with the metal ones. Also, they have to fit snug or that too cause them to fall out and it's the choking thing that could be a problem. However, if you only eat soft foods while you have it in and you try not to chew on that side, you could leave it in with some confidence. Most of the patients that I know who have nesbits remove them during eating and then just pop them back in when they are done.

Chewing is not the real reason for a nesbit because you can usually chew most foods okay without one. The reason to have this appliance is to prevent the adjacent teeth from tilting in towards that open space which can mess up your bite and also to prevent the biting tooth (the tooth directly above or below this space) from drifting up or down into this space. Nesbits are space holders, for lack of a better definition, and for esthetics.

Removable partial dentures are designed for chewing as well as space holders and esthetic reasons.

Given the two other root canaled teeth, #2 and 4 in your case, it is not ideal to put an implant in between these two compromised teeth. It is also not ideal to put a three unit bridge there which would mean grinding down the two root canaled teeth. The trauma from the drilling on these guarded and fragile teeth could set off a huge problem. Also, when one or both of these teeth needs to be removed, the entire bridge becomes useless. It's usually not recommended because it's just not stable.

Bryanna