Regarding bones: Bones alone are not enough for an effective oral hygiene regime. They clean the crowns, but can not reach the subgingival space that periodontal disease starts the way a toothbrush can. Clean crowns look pretty, but are not an indicator of oral health.
Also small breed dogs are more notorious for bad teeth, so like Anon was saying it’s important to teach them about the brush and start them on a brushing routine early. I use a human tooth brush on my big guys. For a small dog you will probably want a baby tooth brush.
Let me add too that I recently spent some time doing a clinical rotation through an emergency clinic for pets and after hearing the surgeons talk about all of the things they have removed from dogs stomachs, I hesitate to give my dogs much of anything to chew on. That being said, I know my dogs chewing habits well and how they will eat anything.
