Repairing damaged teeth:
Fillings work best when there is adequate tooth structure remaining to help support the filling material. Previous large fillings are really a sign of previous damage to a tooth (usually due to decay) and unfortunately teeth aren’t able to heal themselves.
Many teeth with old large fillings eventually succumb to cracks or decay. Back teeth (molars and premolars) that have had root canal treatment, or teeth with “cracked tooth syndrome” are often advised to be restored with a crown or an onlay to protect these weakened teeth long term.
Teeth that have had root fillings have been shown to fail at a much higher rate if they aren’t protected by a crown or onlay.
Gold crowns have been around for many decades and still remain one of the longest lasting restorations dentistry can offer. They are quite conservative and have quite similar properties to natural tooth structure.
There are also a variety of tooth coloured crowns available these days, including beautifully aesthetic high strength ceramics.
These should be more resistant to chipping and breaking than older materials. Also, modern crowns can oten avoid the “black line” that is seen around crowns from previous decades.