YES YES YES YES YES!!!!
It is a MUST DO!
Last year, when Hendrix was 3, I took him to the vet to get his teeth cleaned because his breath was really bad and he had a lot of plaque....
WELL- His teeth were SO bad and dirty that he ended up needing 7 teeth pulled! Nobody had ever told me the importance of brushing his teeth, so I just didn't know any better. But that experience was awful (and EXPENSIVE) so now we try and brush both of our Yorkies teeth almost every day.
I have found that the dog toothbrushes are very hard on their little mouths and the brushes that go on your finger are hard to use..... especially because my dogs mouths are SO small so what I do is I buy baby toothbrushes. I just get the ones from the drug store that are meant for infants or toddlers and they work PERFECT! Plus they are softer
And then I just get a yummy flavored dog toothpaste.
Hendrix doesn't mind his teeth brushed at all anymore.... they key is to start out slowly until they get used to it
Goodluck!