The question of whether to decide in favor of an implant or crown is often irrelevant. In other words: The answer strongly depends on the situation. For instance, when a tooth has decayed so strongly that a filling or inlay are no longer sufficient, it is crowned. However, for crowning to be worthwhile, the existing tooth substance must be sufficient, which is why dental crowns are considered to be measures for tooth preservation rather than replacement. Therefore, whenever a natural tooth can be preserved, it is not necessary to consider implant treatment.
The situation is different when the natural tooth is assumed to have a limited lifespan: Crowning should be foregone whenever root canal treatment has failed or the tooth is dead. Placing a dental crown and subsequently removing the tooth simply costs time, money, and nerves. In this case, you should be sure to give thought to possible alternatives early on and discuss a dental implantation procedure with your dentist.