@kjc48 I am a retired Dental Hygienist, and I think a dental cleaning is a good idea. Let the dental office know of his medical issues and update his medications. I would also suggest that you check his mouth first, (if he will let you) to see if he is brushing well and if there are deposits on his teeth.That could be the source of the problem.

You know your husband best to prepare him for the dentist. I never had problems treating dementia patients. One sweet lady kept talking about her life with her husband from many years ago like it happened yesterday! I hope you have a good outcome.