CASE STUDY #2: Yоu аre wоrking with а 6 mоnth recаll patient that has a light amount of calculus, but several areas of recession/root surface that prevent you from using your sickles everywhere. Your instructor advises you to check out a Piezoelectric ultrasonic to get experience with it before graduation and after using the Piezo, you use the Universal Curets to fine scale the root surfaces. You know that the Piezoelectric ultrasonics are similar to the magnetostrictive ultrasonics in their effectiveness, but you remember that they are adapted differently that the magnetostrictive inserts. Use this information to answer the following questions. QUESTION: Why is exposed dentin a contraindication for using an ultrasonic instrument?