In the 1970s it became clear that the subgingival environment was not accessible to antibacterial agents delivered to the oral cavity in the form of tooth pastes and mouth washes due to their limited ability to penetrate into the subgingival environment (1,2). The irrigation of the pockets with antibacterial agents was found to be clinically ineffective probably due to the rapid washout of the drugs to ineffective levels (3,4). This led to the development of devices that could be introduced into periodontal pockets to deliver their active antibacterial ingredients over an extended period of time (5-10).