How To Remove a Crown

Crowns are one of the longest lasting things we can do. Yet nothing lasts forever. When the time comes to replace an old crown it pays to know the tricks that help you get it off and get that crown prep done quicker.

Porcelain Fused to Metal

Replacing a PFM is pretty straight forward, half the prep is done for you! To remove a PFM follow these steps

  1. Section through the porcelain of the PFM with a diamond bur
  2. Use a cross cut tungsten carbide to section through the metal, make sure you cut all the way through from gingival margin to gingival margin.
  3. Place an instrument between the pieces and separate the sections.
  4. If one part is stuck, just section again.

Why change burs you ask?

If you try section with just a diamond bur it will skip along the metal and not cut efficiently. If you try a tungsten carbide on the diamond it will chip.

When cutting the metal it is worth warning the patient about the noise, it's a little disconcerting for them initially. Forewarned is Forarmed, a post by James, covers this exact topic!

IPS e.max (Lithium Disilicate)

Lithium disilicate is a great material. Although lithium disilicate can be cemented on a retentive prep, most dentists will bond it routinely. Cutting off a bonded lithium disilicate crown isn’t a lot of fun however it can be made easier with a counter-intuitive tip. Use fine diamonds. Get out a pack and prep off the lithium dilsilicate like a regular crown prep. Unfortunately sectioning a well bonded lithium disilicate crown is unlikely to make it much faster.

ZIRCONIA

Similar to e.max, Zirconia is easier to remove with (multiple) fine grit diamond burs. The reason this is better than a coarse grit bur is simple - the material is so strong, it rips the larger diamonds right off the shank!

Zirconia... the material is so strong, it rips the larger diamonds right off the shank

Unlike e.max, zirconia is more frequently cemented with a luting cement and this means that sectioning the crown and attempting to remove in pieces is beneficial.


That said, the future may make this more challenging. With bonding improvements there has been a relatively recent shift towards bonded zirconia. Might need to stock up on the fine diamonds!

 

I'd be stoked to hear if you found this helpful or if there are any other tips for this topic. If so, share it with a friend.

David is a recent graduate dentist working in private practice in regional NSW, Australia. Read more at www.dentalheadstart.com/meet-david/

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