I posted about this problem a few months ago, and unfortunately the problem persists.
My 19 month old Chihuahua will not let me or anyone cut his nails or brush his teeth. No matter how slow or calm or soothing or rewarding I try to make it. He basically works himself into a frenzy getting more and more hysterical.
He hadn't been to the vet in a year, and when he went last week, he was awful! He was screaming and crying like a human child. The vet couldn't even fully examine him, and now we don't even know if all his baby teeth have fallen out.
The vet assistant said she sees this with Chihuahuas, but do you think he could have been traumatized before I got him at 3 months old?
Is it that he's stubborn and I'm letting him get his way?
Why would he be so terrified of these things? As far as I know, he's never been hurt or mistreated.
constantly handling his feet during normal petting sessions can help. I really think that trying to calm or soothe him is a mistake... in a nervous dog, this can acutally make things worse because they are like, "OMG she's trying to calm me down, so this is REALLY a bad thing!"
Instead you want to be upbeat and cheerful.
Regarding messing with your dog's teeth... the best way I've found to deal with a dog that's touchy about its teeth is to put a dab of peanut butter on your finger. In a cheerful tone, say, "Teeth!" and then quickly swipe your finger across the dog's gums. The dog gets used to having its teeth touched, the word 'teeth' let's them know that something involving the teeth is coming, and they get the added bonus of some peanut butter as a super special treat. If you do this 2-3 times a day for a week, you should see marked improvement when you try to see your dog's teeth.
Never trust a tall dwarf... he's lying about something.