The reason for crowning a fractured tooth.

[dentwannabe]

What is the real purpose of crowning a tooth with a fractured cusp?


Aside from the fact that it is "broken" and must be "repaired".

Say there's no sensitivity (tooth is necrotic), no infection, no perio-lucency. Say no need for endo.

Now... am I right in thinking the REASON for doing a crown in this case would be to prevent further fractures. For some reason I remember learning that a fractured cusp compromises tooth structure and its ability to handle stress and so without repairing it there will be a greater chance of another fracture to the tooth. And so the purpose of the crown would be to sort of "hold together" the tooth to allow it to better handle shear forces. IS THIS RIGHT? I know this is very basic, but it got me thinking, what is the proof?

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[La Miraflorina]

Well for one, if the tooth is necrotic, there is a need for endo. And post-RCT the tooth will be brittle, thus requiring a full coverage restoration.

As for the fractured cusp, you have to determine what caused the cusp to break in the first place. Caries? Bruxism? Trauma? Chances are, if the cusp broke on natural tooth structure, it will break much more easily as a foreign material.

 

[dentwannabe]

Well for one, if the tooth is necrotic, there is a need for endo. And post-RCT the tooth will be brittle, thus requiring a full coverage restoration.

As for the fractured cusp, you have to determine what caused the cusp to break in the first place. Caries? Bruxism? Trauma? Chances are, if the cusp broke on natural tooth structure, it will break much more easily as a foreign material.

Okay, you sort of answered my question, thanks. But consider the tooth is vital, one cusp is fractured. WHAT is the reasoning for crowning the tooth?

Basically, is a fractured tooth more susceptible to further fracture than a tooth without a cuspal fracture.

 

[aphistis]

Okay, you sort of answered my question, thanks. But consider the tooth is vital, one cusp is fractured. WHAT is the reasoning for crowning the tooth?

Basically, is a fractured tooth more susceptible to further fracture than a tooth without a cuspal fracture.

...or the missing cusp may result in lost masticatory function, or excessive pulpal sensitivity, or unacceptable aesthetic compromise, or increased caries risk (e.g. fractured tooth contours are difficult to keep clean), or any number of other things.

To answer your question--yes, a traumatically fractured tooth is globally at risk for future fracture, but it has as much to do with external, local environmental factors (i.e., the things that caused the tooth to fracture in the first place are still in place) as with intrinsic compromise to the tooth itself. Careful restorative treatment frequently (though not always) allows the dentist to address these external factors in addition to reinforcing the tooth structurally.

 

[StudentDentist]

But why crown it? Why not build it up with composite, granted it can stand the occlusal load. I don't buy into the reasoning of preventing future cusp fracture. You don't prevent cusps from breaking in the future by removing those cusps with a bur.

 

[aphistis]

But why crown it? Why not build it up with composite, granted it can stand the occlusal load. I don't buy into the reasoning of preventing future cusp fracture. You don't prevent cusps from breaking in the future by removing those cusps with a bur.

A cusp-replacing direct composite restoration is virtually guaranteed to fail due to the mechanical limitations of those restorations. Pure and simple, the micromechanical bonding upon which those restorations depend aren't strong enough to reliably endure under that kind of stress.

Your argument about "removing cusps with burs," etc., is just plain silly. I encourage you to spend some time reviewing your occlusion and single-tooth restorative texts.

 

[StudentDentist]

A cusp-replacing direct composite restoration is virtually guaranteed to fail due to the mechanical limitations of those restorations. Pure and simple, the micromechanical bonding upon which those restorations depend aren't strong enough to reliably endure under that kind of stress.

Your argument about "removing cusps with burs," etc., is just plain silly. I encourage you to spend some time reviewing your occlusion and single-tooth restorative texts.

It sounds silly, and I'd meant it to sound silly. I wouldn't fix one cusp by removing the remaining cusps via a crown prep. There are other, less invasive approaches to this, assuming this is a posterior tooth.

 

[OceanDMD]

It sounds silly, and I'd meant it to sound silly. I wouldn't fix one cusp by removing the remaining cusps via a crown prep. There are other, less invasive approaches to this, assuming this is a posterior tooth.

Onlays, 3/4 crowns are options for those particular cases. I prep more onlay restorations than anything else. If you have a healthy cusp or two there is NO reason to prep for a crown. They are also much more fun to prep than crowns.

 

[teeth63a]

It sounds silly, and I'd meant it to sound silly. I wouldn't fix one cusp by removing the remaining cusps via a crown prep. There are other, less invasive approaches to this, assuming this is a posterior tooth.

I think you have a fundamental misunderstanding of terms.

You're not "removing a cusp" for any fixed pros case...you're reducing the height to allow for the restoration. Like Ocean said, onlay and inlays are a lot more conservative than full coverage. Full coverage is NOT your only choice, especially if you have at least 2 good remaining cusps.

 

[StudentDentist]

I think you have a fundamental misunderstanding of terms.

You're not "removing a cusp" for any fixed pros case...you're reducing the height to allow for the restoration. Like Ocean said, onlay and inlays are a lot more conservative than full coverage. Full coverage is NOT your only choice, especially if you have at least 2 good remaining cusps.

Occlusal reduction. I know what it's called, but this isn't a vocabulary test. I don't think I'd ever prevent fracturing of the adjacent cusps by removing nearly all the enamel on the tooth ("the crown prep"). It'll get the job done. I mean, how can more enamel fracture when you've removed it all? Anyway, I'm just alluding to better alternatives to a FVC.

 

[aphistis]

Occlusal reduction. I know what it's called, but this isn't a vocabulary test. I don't think I'd ever prevent fracturing of the adjacent cusps by removing nearly all the enamel on the tooth ("the crown prep"). It'll get the job done. I mean, how can more enamel fracture when you've removed it all? Anyway, I'm just alluding to better alternatives to a FVC.

You mean like the onlays and partial crowns everyone is trying to tell you about?

 

[StudentDentist]

You mean like the onlays and partial crowns everyone is trying to tell you about?

Yes, they're what I've been alluding to from the start.

 

[HupHolland]

Yes, they're what I've been alluding to from the start.

Pretty sure you mentioned building the tooth up with composite, not onlays.

Hup

 

[aphistis]

Yes, they're what I've been alluding to from the start.

You are aware, then, that onlays and partial crowns require occlusal reduction very similar to that required for full coverage crowns?

 

[dentwannabe]

I think in principle we're all agreeing to practice conservative dentistry.. What type of restoration is really case specific.

thanks guys