There are many signs of dental disease such as tartar, gingivitis, bleeding, not eating. Sometimes your veterinarian can see a tooth that’s loose or that the enamel is damaged. The tricky part is that teeth are like little icebergs and much of the tooth is below the gum line.
This is a classic tale, but perhaps one where the warning is often ignored. Do NOT feed hard toys, bones, antlers etc to your dog. It can and will break their teeth.