I had a lot problems with my Yorkie, Katie, who has since passed away.
I did not get her from a breeder (so I'm not sure if I should post in this thread because this is for people who got their dogs from BREEDERS, I got Katie from a pet store) but I've learned my lession and in the future, I will never buy from any pet store again. Katie was diagnosed with severe kidney disease at a little over a year old.
My Maltese, Codie, (also got him from a pet store) had a luxated patella in his rear left leg but we had surgery to fix it. He also has bad teeth and weak gums but I feed him good quality food, brush his teeth daily and he gets cleanings from the vet when needed. I'm trying to keep that problem in check ... I don't want him toothless by the time he's 5 years old.
Thanks to the daily brushings, his teeth are usually sparkly white. He may not have the best teeth but he doesn't have ANY tear staining which is usually sooooo common in the Maltese breed!
On a positive note, my Cali (got her a breeder) is in tip top excellent health.
(Sorry to digress but I always like to end on a positive note).