If you maintain the Dental Crowns and Bridges properly then they may last you from between 5-15 years.
Numerous factors such as loosening of implant screw, breakage in abutment, and decay in dental cement can loosen the dental implant.
It largely depends on the situation of your dental condition. Ideally, bridges are better for replacing more than one tooth, whereas for single tooth replacement dental crowns are better.
It is not the Dental Crowns and Bridges that smell but the germination of bacteria within them due to stuck food that causes the smell. It occurs when there is a space between the gums or adjoining teeth.
You should skip on chewing gum or eating foods that require too much chewing because it could loosen the bridge or even break it after a certain time period.