The best dentistry is no dentistry.
Nothing lasts as long in the mouth as your own natural tooth structure. Sometimes though, things go wrong and teeth either decay or fracture from use or trauma. When teeth need to be fixed or restored, you want to be as conservative as possible and use the very best materials to fix the problem.
There are many different materials today that dentists use to restore teeth. Gold has been found through years of research and evidence to be the longest lasting, most biocompatible material available. Period.
Of course, the best place to use gold is in the posterior or back of the mouth. Gold can be made to look inconspicuous and highly esthetic. You would want to use porcelain or white composite restorations in the anterior or front of the mouth. Crowns or caps cover the entire tooth but they are very destructive. Dentists need to remove excessive amounts of good tooth structure to fabricate the crown.
Gold restorations can be much more conservative. Only the damaged part of the tooth has to be removed. Dentists using gold can place partial caps in gold and leave the undamaged part of the tooth alone. This is a much more conservative and healthful approach.