Ignoring ferrule requirements (especially endo-treated teeth)
What it is
Restoring a tooth — most critically an endodontically treated tooth — with a crown/post-core without an adequate ferrule, meaning there isn't enough sound, continuous coronal dentin above the finish line for the crown to "brace" the tooth. A commonly recommended target is about 1.5–2.0 mm of dentin height for ferrule when feasible.
Why it happens
• Caries/fracture/large access + old restorations leave minimal remaining tooth structure, but the case proceeds to a crown anyway • Margin placed too apically (deep subgingival) to "hide" defects, yet the remaining axial walls are short/weak and ferrule is still absent • Over-reduction + over-taper during crown prep shortens walls further, unintentionally destroying potential ferrule • Over-reliance on the post ("the post will reinforce it") — posts mainly retain the core; ferrule is a major factor for fracture resistance/survival
The full clinical mistake entry includes
- How to avoid it — the prevention protocol
- The clinical tip experienced clinicians use
- The documented reference behind the mistake
More clinical mistakes
Dentalverse is an educational resource for dental students and dentists. This page is a study reference — it is not medical advice and does not replace clinical judgment. Always follow your institution's protocols and your supervisor's guidance.