Pam,
Sorry to hear this, but as everyone has said, your dad is in the best possible hands now and the hospice nurses will do everything they can to make your dad as comfortable as possible. I was there beside my dad most of time when he was in the hospice and I know how much it meant to him, and I know what it will mean to your dad to have you there beside him as well.
That is great that your dad got his teeth cleaned, and yes, the next time he goes make sure they do it right!
Best wishes to you and your dad,
Gavin