Brief Answer: could be a side effect of the solution. Detailed Answer: Hello There, It is very nice to hear that you are taking an adequate care from your side by brushing your teeth, using antiseptic mouthwash gargles, thus taking complete care. Listerne is an alcohol containing mouthwash which has a most common side effect of causing dryness in the mouth and burning sensation; sometimes mouthwash can also cause staining in the mouth. Perhaps the brown threads may be from the mouth wash. Other then this it could be related to caries formation, smoking, acid reflux, use of certain medications. I would suggest you to stop listerine for couple of days and see if that makes a difference. If it doesn't then I would suggest you to consult a DENTIST get a thorough checkup done and take a complete oral health care information. You may need to undergo a thorough scaling and polishing done once in every six months. Hope you find this as informative and helpful, Regards, Dr Qazi Ammara.

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