The purpose of this study is to evaluate patients with emergency pain and a sore (infected) tooth to determine if immediate root canal therapy is better at reducing pain, when compared to initial treatment with antibiotic and pain medication followed by root canal therapy. Each participant will be randomly assigned a number, which will determine if they will receive initial endodontic treatment that day or at a later date. Each participant will receive an anesthetic injection, pain medication and a prescription for an antibiotic. They will be asked to keep a diary to record their pain level after the injection and their pain levels and the amount and type of pain medication taken each day for the next 5 days. Participants who did not receive root canal therapy at the initial appointment will receive it after the 5 day postoperative period. The pain levels and medication use will be compared between the treatment and nontreatment groups.