How old is my adopted dog? Grey muzzle, white teeth, worn incisors.

Chance is a handsome boy! I will give his age my best guess! From the pictures, I would say he's a couple of years old, maybe between two and four years old. I wouldn't class him as a senior dog (over seven), but he looks older than a year. He does have lovely white teeth, but it's hard to age a dog based solely on it's teeth. A senior dog who is around 10 could have better teeth due to regular dental than a younger dog who is allowed to chew bones and has no dental care. His eyes look bright and clear, which leads me to believe he is younger than a senior dog. As for the grey hairs on his muzzle, it could be part of his normal coat, but dogs as young as four to five can start having grey hairs. Anyway, I hope this helps, a vet who sees him in person may have a better estimate than I do :-)