What should be the maximum diameter of a bur for post preparation?

The maximum diameter of a bur for post preparation is typically recommended to be 1/3. This size balances the need for sufficient space to create adequate retention and resistance for the post while minimizing the loss of remaining tooth structure. Using a bur with this diameter allows practitioners to ensure that the canal is appropriately enlarged for the post, enhancing the strength of the final restoration while maintaining the integrity of the tooth.

Choosing a bur that is too large could compromise the tooth structure, leading to a higher risk of complications such as fracture or weakening of remaining tooth material. This aspect emphasizes the importance of careful planning in post preparation to ensure a successful outcome for restorations.