A toothache is a pain in or around a tooth that may be caused by: 1  Tooth decay. 2  Abscessed tooth. 3  Tooth fracture. 4  A damaged filling. 5  Repetitive motions, such as chewing gum or grinding teeth.
A correlational study determines whether or not two variables are correlated. This means to study whether an increase or decrease in one variable corresponds to an increase or decrease in the other variable.
Correlation is a statistical technique that can show whether and how strongly pairs of variables are related. For example, height and weight are related; taller people tend to be heavier than shorter people. The relationship isn't perfect.