If you can't get the toothpaste made for dogs then yes you can make a toothpaste for your dog by mixing baking soda with some water.
Mix the baking soda and water until it's a paste and then get a toothbrush that's made for dogs and then you can brush your dogs teeth with the baking soda and water solution.
Never use human toothpaste since the toothpaste for humans contains fluoride which is poison to dogs.