Which tool is primarily used to clean hard-to-reach areas and the grooves of the teeth?

The disposable prophy brush is primarily used to clean hard-to-reach areas and the grooves of the teeth because it is designed with soft bristles that can effectively polish and clean surfaces that may be difficult to access with other tools. Its flexibility allows for thorough cleaning, especially in areas around the grooves and pits of teeth where plaque and debris tend to accumulate. This tool is often used in conjunction with prophylactic pastes during dental hygiene procedures to provide a smooth finish and ensure that all surfaces are adequately cleaned.

In contrast, other tools like dental scalers are typically used to remove calculus and tartar from the tooth surfaces, while floss is essential for cleaning between teeth, removing debris, and preventing gum disease. Toothpicks can be used for manual removal of food particles but do not provide the same level of cleaning for grooves and hard-to-reach areas as a prophy brush does.