Which tooth is noted for having the worst crown:root ratio when evaluated through past-ortho radiographs?

Tooth #9, which is typically the maxillary left central incisor, is recognized for having the worst crown-to-root ratio, particularly when evaluated with orthodontic radiographs. This tooth often exhibits a relatively short root structure compared to its crown height, which is a crucial factor in determining stability and support during orthodontic treatment.

When analyzing crown-to-root ratios, a lower ratio indicates less root support for the crown. This can impact the tooth's ability to withstand occlusal forces and may be associated with a higher risk of periodontal issues or increased mobility. The ratio becomes particularly important in orthodontics, where forces are applied to teeth that may already have compromised root support.

In contrast, the other teeth listed typically possess a more favorable crown-to-root ratio, indicating stronger anchorage and potentially leading to better outcomes regarding stability during and after orthodontic procedures.