Occasionally a tooth can become broken down due to things such as large cavities and fractures. First and foremost, cavities must be cleaned out all the way to clean tooth structure and a filling must be placed to fill the void. However, in certain cases, the filling becomes so large that certain thin parts of the tooth are structurally at risk of breaking. This is when we will suggest a “crown” or a “cap.” This restoration wraps all the way around the tooth and prevents thinner parts of the tooth from breaking off. Think of it as analogous to a lid on a shoebox. When the lid is on, it is more difficult to pull the sides of the box apart.