Phencyclidine (PCP) was originally developed as an anesthetic, but the adverse side effects prevented its use except as a large animal tranquilizer. PCP acts as both a depress â¦ ant and a hallucinogen,and sometimes as a stimulant. It is abused primarily for its variety of mood-altering effects.
1 An inlay- As the name suggests, this restoration sits inside the tooth.  An onlay- In contrast is bonded on top of the tooth, replacing some or all of the cusps of the tooth.
Direct Onlays -- For direct dental onlays, the same preparation is used, and the tooth is filled with composite resin material. Traditionally, the filling is molded and hardened in an oven and then cemented to the tooth.