Hi
It depends on the patient's maintenance and general health condition ,If the patient's maintenance is excellent,if patient's maintains good oral hygiene and surrounding structure around the cap, it will last for 10-25 years If not,It can get fractured within 2-3 year's.
Same applies to implants,the only difference is your bone,as long as your bone is healthy and sound around the implant nothing will happen,extra and maintenance plays very important role
Health Tips
*Maintain good oral hygiene and health
*Avoid sticky food,hard food
*Regularly flossing
*Frequent visit to your dental surgeon for check up for every 6 months