I use a lot of the vet recommended dental chews! My 5 year old yorkie had one tooth pop out during his last cleaning
And 1 year old Baron has already had a professional teeth cleaning (during his neuter at 9 months old). My vet said with some Yorkies there is nothing that can ward off needing regular dental cleanings. I guess some are more prone that others.
I also brush their teeth at home, but probably not as much as a should because they are such pains about it