Orthodontically induced inflammatory root resorption (OIIRR), is a certain adverse effect of force application. The extent of this inflammatory process depends on factors such as the virulence or aggressiveness of the different resorbing cells, and the vulnerability and sensitivity of the tissues involved. Unfortunately root resorption does not receive the considerations it is due. The lecture will discuss current issues related to the OIIRR and will focus ways to control OIIRR during treatment and individual variation and susceptibility that still remains beyond our understanding.