The term 'Canine Covering' can be broken down into two crossword solutions: ENAMEL (6 letters) and CROWN (5 letters). ENAMEL is a hard, glossy, protective coating that covers the CROWN of a tooth. It is made up of calcium phosphate and other minerals and is the hardest substance in the human body. The CROWN of a tooth is the part of the tooth that is visible above the gum line. It is composed of ENAMEL and dentin and is the most visible part of the tooth. Together, ENAMEL and CROWN make up the canine covering, which is the outermost layer of a dog's tooth.