The key is that the porcelain crown is sleeved on the abutment. If it is not made tightly, or it is purely occlusal interference, food will invade and corrode the abutment, and the cusp injury will lead to porcelain collapse.
If doctors should pay strict attention to the above two aspects under reasonable indications, that is, to make a porcelain crown, and of course patients should also pay attention to cleanliness to reduce the chance of trauma, then the ideal porcelain crown life should be 20-30 years, or even longer.
The above is the standard schematic diagram of porcelain crown preparation. As long as the above standards are mastered, the service life of porcelain crown can be guaranteed.