All dentistry fails given a long enough period of time regardless of how good the dentist is. A good dentist makes things fail at the slowest possible rate...But fail he or she will because all materials have a life expectancy...You don't buy one car, one shirt or one pair of shoes in your life, why would anyone expect that a tooth would have the same filling or crown for 50 years?
This is what a 25 year old tooth looks like that has been covered by a crown:
The brown color is really tooth decay because the crown leaked saliva under the crown. The brown tooth on the right has become so weak that it has fractured and needs to be extracted.
I would like to suggest to you that when I recommend having a new crown on your tooth after 25 years that you listen. When a tooth has rotted to the point that it cannot be saved, you will have to extract the tooth, graft the area, have an implant placed and a crown. The total cost for this treatment is $5,000+.
The cost of a new crown is $1650.
I truly want to save you money...When it is time to have a new crown even though you feel no discomfort...Please consider my recommendation.
(Aside: This is also why it is important to delay the placement of a crown until you are older. Again, if you want to save money: A direct bonded resin filling in my office is $325-$400 and a crown is $1650...It is NEVER about the money but taking care of you so that you can save all your teeth.)