Please,sir my first time using online doctor for...

what is the treatment of toothache ?
the treatment of toothache is treated by non steroidal antiinflammatory drugs such as ibuprofen 600 mg 3 times a day and in case if you have an infection then an antibiotic is given to the patient such as augmentin 875 mg 2 time a day for 7 days but in some cases you might need to be treated surgically in case of dental abcess or in case of tooth decay and you need a root canal 
is it ok for me to use antibiotic without visiting the doctor ?
no its not ok because it will not going to help you if you dont have a bacterial infection and only you should take an antibiotic drug after dentist examination 
what are the possible causes of toothache ?

• sinus infection 
• tooth decay 
• temporomandibular joints diseases ( arthritis dislocation e.t.c....)
• gingivitis ( tooth gum inflammation ) 
• dnetal abcess

what are the most common diagnostic tests for toothache?
the clinical examination and the past medical history are basic for the diagnosis of toothache and in some case the docrot might order a radiological picture for your teeth such as panorama or CAT scan of the teeth 
what is the advice ?
toothache is considred one of the most painful pain type in the human body so its an urgent situation ,  thats why we urge you to to visit a fentist as soon as possible for the right dignosis and the correct treatment 
and remember that painkillers are for pain but antibiotics are for bacterial infection and not for pain so in your case you need a painkiller and dont use ani antibiotic uness seen by a dentist or a medical doctor