The back teeth (the molars & premolars) are thick and broad. If there is a decay in the contact area between 2 teeth, I won't be able to see it during visual clinical examination when it is still small --- which can be easily fixed with a simple filling. By the time I can see it, it is often very deep & close to the pulp of the tooth, or already gone into the pulp, exposing the nerve. You may then need to do a root canal treatment, or have the tooth out. So it makes sense to invest in the xrays on a regular basis.
