Bones can be pretty hard on their teeth and can cause a medical emergency if a bone splintters off and they swallow it. Yorkies aren't like big dogs and really shouldn't have bones (big dogs shouldn't either).
There are lots of chew toys that you can buy to help with teething and cleaning teeth (as well as brushing). I like the C.E.T. chews I buy from
EntirelyPets Discount Pet meds Pet Supplies & Flea Medicine not only do they help clean their teeth by scrubbing them while the dog chews they have an enzymatic cleaner embeded to kill germs and freshen the breath. You can use them every day but I usually give them every 2-3 days. I also like the Himalayan Chews you can buy from a fellow Yorkie Talker on here, & the dogs really enjoyed them too.
Teresa