Generally, nothing happens to the dental crown. Of course, they can break or chip but majority of the time, what causes the failure is the tooth under the crown. As most teeth with crowns are badly damaged before placing the crown, this can shorten the life of the tooth even with crown on top. Overall, the healthier the tooth when crown is placed, the longer it will last. Teeth beneath a crown can still decay in areas not covered by the crown or may crack over time, especially if they’ve been root canal treated and are subject to heavy biting forces. On average, crowns are expected to last around 10 years or longer.
Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.