Nogueira BML, et al. - Researchers performed a systematic review to assess if the use of dexamethasone was effective in controlling pain associated with symptomatic irreversible pulpitis. Administering 4 mg dexamethasone either by mouth or through intraligamentary and mainly supraperiosteal injections into the root canal could reduce the pain felt by patients diagnosed with symptomatic irreversible pulpitis for up to 24 hours.