A distinctive clinical entity originating as a proliferative response of the soft tissue of the oral mucosa to a non-specific irritant is called

The use of aspirating syringes for the administration of local anesthetics is
recommended because
1. the effectiveness of local anesthesia is increased.
2. aspiration of blood is proof that the needle is in an intravascular location.
3. their use removes the hazard of rapid injection and provides a distinct saving of time.
4. their use reduces the frequency of accidental intravenous injection.