 Lasers may be fast but have not been shown to thoroughly disinfect the whole tooth, and may cause damage.Several randomized clinical trials concluded that the use of rotary instruments is associated with a lower incidence of pain following the endodontic procedure when compared to the use of manual hand instruments.Corticosteroid intra-oral injections were found to alleviate pain in the first 24 hours in patients suffering from symptomatic irreversible pulp inflammation.