Butler G-U-M Rincinol P.R.N Oral Rinse, Canker Sore Pain Reliver 1770R, 4 Oz.Braces Introducing the pain-free way to relive canker and mouth sore pain. No harsh hydrogen peroxide or painful benzocaine which means no numbing, stinging or burning. Rincinol P. R. N. gently forms a micro-thin, invisible, bioadhesive protective barrier over sores which promotes healing and prevents air, liquid, and food from irritating the sensitive nerve endings.This soothing oral bandage provides up to 6 hours of pain relief.