I have no idea on this earth why the bun has not recieved treatment, unfortunately all i can do is advise.
I have no idea what this bun has left teeth wise, as i cannot get near it and check. All i know is its front bottom teeth used to grow and they needed clipping every 5-6weeks.
I dont know how the bun lost its teeth, i only know by overhearing it been shouted literally "its tooth has fallen out"