Evaluation of the cleaned teeth can be performed by air drying the teeth or applying a special solution to the teeth. When the air drying technique is used, the teeth are gently air-dried. If the teeth appear dull and frosted, they still have calculi adhering to them. When the special solution is applied, the dye in the solution will bind with any plaque and calculus left on the teeth, thereby coloring the affected teeth. If an evaluation indicates that calculus is still present, the affected teeth will be re-cleaned, re-polished and re-flushed. At this point, fluoride application may or may not be performed. Fluoride binds the tooth surfaces and may help to reduce sensitivity and plaque formation.