Final answer:
The correct intervention for an avulsed tooth is placing it in milk to maintain the cells' viability. Handling the root or using povidone-iodine can damage the tooth, while dry storage leads to cell death. Streptococcus mutans is the key bacteria contributing to tooth decay.
Step-by-step explanation:
When an alert adult patient has a tooth avulsion and immediate reimplantation is not possible, the appropriate intervention for the emergency nurse is to place the tooth in milk. Milk acts as a temporary storage medium that maintains the viability of the periodontal ligament cells on the avulsed tooth. It is crucial to avoid handling the tooth by its root to prevent damage to these cells. In contrast, soaking the tooth in povidone-iodine is not recommended, as it can damage the periodontal ligament cells, and wrapping the tooth in dry sterile gauze can lead to cell desiccation and death.
Microbes play a significant role in tooth decay, and the most important cariogenic species of bacteria is Streptococcus mutans. This bacteria adheres to the tooth surface and metabolizes sugars to produce acid, which in turn demineralizes the tooth enamel and dentin, leading to caries. If caries develop, prompt treatment such as drilling and filling, or root canal in advanced cases, can prevent the worsening of the condition.