The problem is not the white filling, but the judgement and skill used in fabricating it. Placing a very large filling very close to the pulp (nerve) will result in problems down the road, regardless the type of restoration used. White, composite fillings should be placed in smaller cavity preparations, leaving most of the tooth intact. If most of the tooth is destroyed, one should consider a more appropriate restoration, such as a crown. A root canal treatment should be performed ONLY if the tooth requires it. And a post should be placed ONLY to retain a core build up, if there is not enough tooth structure to support a crown.
The best advise I can give you is to find a high quality dentist, or better yet,a prosthodontist, who is the specialist in this area, and have a proper diagnosis of your situation.Best of luck.