Re: deep white filling not sure if this is still normal!!!
Sometimes when a tooth has been filled so many times it just doesn't have the ability to repair itself anymore. Overtime when fillings are made, the inside lifeline of the tooth shrinks back in an attempt to save the tooth from further damage. Thus the blood supply inside the tooth gets smaller and smaller. When a tooth is filled again the tooth cannot protect itself and starts to die. Bacteria can enter the tooth without the body defending the tooth and they then multiply. You start to get an infection which can then turn into an abscess. Root canal treatments are not that bad, the worst about it is having to spend to long in the chair.
There is a lot of old wives tales about them, yes they can hurt if the tooth is very infected, but everything is painful when very infected. If the tooth is already dead you feel no pain, and the dentist should place a local anaesthetic into the tissues to relieve any discomfort. Molar root canals take more time and it is very difficult for the dentist to do, most dentists hate doing them because they are so fiddly and they actually hurt the dentist in their back, eyes, fingers and head because they need to concentrate so much.
Dentists are human - don't expect miracles, if the tooth can't be saved it should be removed.