The primary reason a crown fails is due to tooth decay forming around its edges, rather than the crown itself breaking or fracturing. To ensure your crown lasts as long as possible, it is essential to maintain excellent oral hygiene. This involves brushing the crown, flossing around it, and using interdental brushes, just as you would for your natural teeth. These practices are crucial for preventing both tooth decay and gum disease, which are the main threats to the longevity of your crown.