Hi.
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concern..
As per your complain upper back teeth are located in close proximity with the sinuses and deep infection in tooth can at times cause infection in sinuses leading to pain and other symptoms of
sinusitis..
As far as numbness in teeth and roof of mouth is concerned it is due to
sinus infection only while the black discolouration of tooth is due to tooth decay..
I would suggest you to consult an Oral Physician and get an x ray of tooth done to rule out the severity of decay and if the nerves are exposed then
Root Canal treatment has to be done..
In case of superficial decay normal filling can be done..
I would also suggest you to consult an Otolaryngologist and get evaluated and a thorough clinical evaluation and investigations like PNS view x ray or MRI scan can help in diagnosis and treatment can be done accordingly..
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..
Avoid spicy and chilled foods..
Do warm compresses around nostrils..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.