Grinding teeth at the owner is not a sign that the dog hates the owner. Dogs are possessive of their own territory and food. If someone approaches the dog, they will sense a threat and bar their teeth as a warning, sometimes even It will howl loudly to the owner. When this happens to the dog, the owner can train it appropriately and prepare snacks that the dog likes to eat. If the dog is willing to share and let you approach its territory, then the owner can reward the dog with snacks.