My mother has green mucous and pain in her nose after a tooth extraction. her dentist checked everything and said that this is normal. is this right?

Possible Sinus.: On occasion when an upper molar tooth is removed, an opening to the hollow sinus at the root tips can occur leading to sinus infection. An eval from a dentist or oral surgeon can help...it's not always readily apparent.

Yes: Was the tooth removed an upper tooth? When upper posterior teeth are removed sometimes bacteria can enter the sinus, as some of these teeth terminate in the sinus, causing a sinus infection. This would explain the green mucus from the nose. This is usually resolved with antibiotics and decongestants. This can sometimes just happen.