About five months ago i had a filling in my molar tooth, since then it was sensitive to cold and hot. About a week ago it became painfull, it's a constant pain, i took some ibuprofen for couple days, but then another tooth became painfull when bitten on. I took some nimesulide, which is anti inflamatory, that helped, but the molar is still painfull as soon as i stop taking nimesulide. Can it be root infection?