Thanks you both for your help.
She doesn’t have root canals as I know. Her teeth are pretty good. She had the braces for the last three years and taking very good care of her oral care. Anyway, during her 20 years of sinusitis, she has good teeth, but the gum got inflammation very easily due to poor oral care in the old time.
I look at the oil-pulling forum before I reply to you. Seem like the same as mouth wash, what’s different from using Listerine?