How long does “stinting” teeth together last?

My lower 4 front teeth are crooked and have signs of bone loss. I have periodontitis and the dentist wants to do intense scaling cleaning. She says that by removing all the plaque behind these teeth, they may become loose and fall out or need to be pulled. I am only 49 and do not wish to have the interim partial she recommends @ $750 not covered by my insurance. She said she could stint them together for $300 (still not covered). How long does this type of fusing/stinting usually last? I eat healthy and in good physical health, brush twice a day, floss in the evening, and use mouthwash in the morning. What are my other options here?