A 14-year-old has avulsed his maxillary left central incisor. Before replantation, what should you do?

Before replanting an avulsed tooth, it is crucial to properly handle and prepare the tooth. Gently rinsing the tooth surface with saline is the recommended action because it helps remove any debris or contaminants that may have adhered to the tooth since it was avulsed, without causing further damage to the root surface.

Saline is isotonic and will help clean the tooth without harming the periodontal ligament cells that are critical for successful replantation. These cells are sensitive and can be easily disturbed or destroyed by harsher cleaning methods or inappropriate solutions.

The other actions presented, while relevant considerations in different contexts, do not align with the immediate steps necessary before the replantation of an avulsed tooth. For example, performing root canal therapy should not be done prior to replantation unless the tooth is non-vital and has already been evaluated. Soaking the tooth in fluoride solution is not advisable in acute scenarios like avulsion due to potential harm to the periodontal cells. Lastly, vigorously curetting the socket can lead to further trauma and damage, making successful reattachment less likely.