Hi.. Thanks for the query.. As per your complain an abscessed tooth can be a culprit for recurring sinus infections But it is true in case of infected teeth in upper jaw.. The roots of the upper jaw teeth lies very close to the floor of maxillary sinuses and at times even some root tips can be present within the sinuses and any infection that infects the teeth can reach the sinuses causing infection and inflammation of the sinuses.. As the sinuses are inter-connected, therefore multiple sinuses can get infected leading to the symptoms of sinus congestions, facial pain and headache, pressure and pain behind eyes and blurred vision due t pressure caused by the inflamed sinuses as major group of sinuses are present behind the eyes.. Therefore an abscessed tooth if left untreated can cause sinus infections and all the symptoms that you are experiencing can be very much due to severe sinus infection and not necessarily due to any other problems.. So if I would be your treating doctor I would first of all take an x ray of the abscessed tooth and if it can be saved root canal treatment will be done followed by a course of antibiotics and painkillers.. After this you would be referred to an ENT Physician and he can do sinus x rays and advise you proper management like you can be advised a course of antibiotics, anti-inflammatory painkiller like Ibuprofen, decongestants like Pseudoephadrine, do saline nasal irrigation, steam inhalation and use a humidifier in your room.. You can also be advised decongestant nasal sprays containing Xylometazoline or Oxymetazoline.. In case if it still does not get better with conservative treatment then Endoscopic sinus surgery can be advisable.. Hope this information helps.. Regards.