After how many hours is the chance of an avulsed tooth successfully recovering diminished?

The best answer is that the chance of successfully re-implanting an avulsed tooth diminishes significantly after two hours. When a tooth is completely knocked out, the periodontal ligament and surrounding tissues need to remain viable for reattachment. Within the first hour after avulsion, the likelihood of successful re-implantation is highest, and appropriate measures should be taken immediately to preserve the tooth.

After about two hours, the ability of the periodontal ligament cells to survive decreases due to lack of nourishment and oxygen, which they derive from being in the tooth socket. If the tooth is replanted after this time frame, the cells may not be viable enough to re-establish their connection to the alveolar bone properly, leading to a higher chance of failure.

While still possible, re-implantation beyond the two-hour mark presents greater challenges and a lower success rate as the biological factors required for reattachment continue to decline. Thus, emphasizing the importance of quick action and appropriate storage solutions for an avulsed tooth (like keeping it in saline or the patient's own saliva) until professional treatment can be obtained is crucial to increase the chances of a successful outcome.