The functional performance of teeth are determined primarily by their Shape and Size. When Dr. Procopio does a filling, she carefully makes sure it replicates the shape of the previous tooth. This way the functional performance of the tooth is unchanged, and of course we make the tooth look as natural as possible, too.
See if you can find the tooth that has the filling by studying the photo below.
Did you find it? See the marked area in the photo below.