Inhibition ofProstaglandin E2an Interleukin 1-Production byLow-power Laser Irradiation inStretched HumanPeriodontal Ligament Cells

Itiswell-known thatorthodontic treatment usually causes somediscomfort andpaintothepatients. Recently, ithasbeenreported thatlow-power laser irradiation iseffective inreducing thepainaccompanying tooth movement. However, themechanism ofsuchpain relief cannotbe elucidated. Sincehighlevels of prostaglandin (PG)E2andinterleukin (IL)-1 arefoundin theperiodontal ligament (PDL) during tooth movement, and bothfactors areinvolved intheinduction ofpain, theeffects oflow-power laserirradiation on PGE2andIL-1lB production instretched humanPDLcells werestudied in vitro. ThePDLcells, derived fromhealthy premolars extracted fororthodontic treatment, wereutilized for experiments. Cells wereseeded inflexible-bottomed