###Human: I have pain in my decayed tooth even after filling. Could this be an infection? ###Assistant: Hello,  Welcome to icliniq.com. Yes, you are certainly correct. Do warm saline gargle three to four times a day. Your dentist should have taken an x-ray before filling it. Please take tablet Sporidex (Cephalexin) 500 mg 1 tablet twice after meals for five days, Metrogyl ER 1 tablet twice after meal for five days, Zerodol SP (Acaclofenac and Serratiopeptidase) 1 tablet twice after meal for five days, Rantac D (Ranitidine) 1 tablet twice before meal for five days. Your doubts are certainly correct, later you might need a root canal or extraction to eliminate the cause completely. Please do not worry so much it is nothing serious and it will subside once you are on these medications and get proper treatment. I hope this helps. Periapical abscess. Root canal or Extraction. Warm saline gargle. Betadine mouth rinses twice or thrice a day. After seven days.