An endodontic probe is used to perform disinfection procedures on target tissues within root canal passages and tubules. The endodontic probe can include an electromagnetic radiation emitting fiber optic tip having a distal end and a radiation emitting region disposed proximally of the distal end. According to one aspect, the endodontic probe can include a porous structure that encompasses a region of the fiber optic tip excluding the radiation emitting region and that is loaded with biologically-active particles, cleaning particles, biologically-active agents, or cleaning agents for delivery from the porous structure onto the target tissues. Another aspect can include provision of the endodontic probe with an adjustable channel-depth indicator, which encompasses a region of the fiber optic tip besides the radiation emitting region and which is movable in proximal and distal directions along a surface of the fiber optic tip to facilitate the provision of depth-of-insertion information to users of the endodontic probe.