Need Opinions - Can this likely be crowned?

[SonicExplorer]

Hi,

About 40% of the #30 (lower right molar) cracked off. See photo... Can this likely be crowned, assuming the integrity of the rest of the tooth is in good shape? My concern is the fact it cracked at the gum line (no pain tho). I'm hoping a skilled dentist can use that edge as the crown margin on that side? Just wanted to get some opinions to be better armed before seeking dental help.

Sincere thanks,

Sonic

 

[Dr M]

A crown might be possible. If the pulp chamber is close to being exposed, an additional root canal might be needed.
Do you perhaps have an x-rays?

 

[SonicExplorer]

Yep, here's the wings and panoramic. Taken about 18 months ago right before I got the first few crowns done - so of course not reflecting the recent #30 break. Mouth always in great shape, never any issues or disease, only fillings as a young kid. But after having them filled 2 or 3 times during my lifetime they are now starting to fracture...

 

[Dr M]

Should be possible to crown this tooth

 

[SonicExplorer]

Much gratitude for the replies.

Do the X Rays provide any insight as to the likelihood for root canal / pulp chamber being exposed? Asked another way, Is your inclination the tooth can likely be crowned with just a prep/build up?

 

[SonicExplorer]

Forgot to ask, might an on-lay be another/better alternative to a crown in this scenario?

 

[MattKW]

It's a bad break because it has gone below the gumline. A crown will not get much grip on the broken side (lingual). If you try another gold crown as on the adjacent tooth (I love gold crowns), it may well fail. Even building up some sort of core (pin retention?) is not much better.
You need a bonded ceramic crown (or onlay encompassing the buccal cusps) and still cross your fingers for the long term. I would design the crown/onlay with quite flat lingual cusps with no contact during normal lateral movements. Sometimes we have to make a compromise if you want longevity.

 

[SonicExplorer]

It's a bad break because it has gone below the gumline. A crown will not get much grip on the broken side (lingual). If you try another gold crown as on the adjacent tooth (I love gold crowns), it may well fail. Even building up some sort of core (pin retention?) is not much better.
You need a bonded ceramic crown (or onlay encompassing the buccal cusps) and still cross your fingers for the long term. I would design the crown/onlay with quite flat lingual cusps with no contact during normal lateral movements. Sometimes we have to make a compromise if you want longevity.

Thanks. I understood everything except the 'why' regarding a ceramic crown. Can you please elaborate why you suggest a ceramic crown is recommended over a gold crown in this instance? (Is bonded ceramic a 3D printed/Cerec type of crown?)

Thanks

 

[MattKW]

Gold crowns are not glued onto a tooth. Although a cement is used, the cement (glue) may stick (adhere) to the tooth, but will not stick to gold. So, in most situations with gold crowns, we want a lot of tooth structure with parallel sides so that the grip is more frictional than adhesive. The gold crown on your 2nd molar will be "glued" like that, and that's how most gold crowns are done. Similarly for zirconia crowns (which are a non-silica-based ceramic), it is technically very difficult to get a "glue" that sticks to the zirconia, so you want as much tooth structure as possible.
Your fractured molar has very little real tooth left, so you would want a silica-based ceramic or a resin-crown which will allow a "glue" to stick reliably both to the tooth AND the crown. CEREC crowns are typically zirconia, although I think they make a resin type too. The main advantage to a CEREC crown is that it can be made on the same day as the preparation of your tooth - that's it, no special physical qualities.

 

[SonicExplorer]

Gold crowns are not glued onto a tooth. Although a cement is used, the cement (glue) may stick (adhere) to the tooth, but will not stick to gold. So, in most situations with gold crowns, we want a lot of tooth structure with parallel sides so that the grip is more frictional than adhesive. The gold crown on your 2nd molar will be "glued" like that, and that's how most gold crowns are done. Similarly for zirconia crowns (which are a non-silica-based ceramic), it is technically very difficult to get a "glue" that sticks to the zirconia, so you want as much tooth structure as possible.
Your fractured molar has very little real tooth left, so you would want a silica-based ceramic or a resin-crown which will allow a "glue" to stick reliably both to the tooth AND the crown. CEREC crowns are typically zirconia, although I think they make a resin type too. The main advantage to a CEREC crown is that it can be made on the same day as the preparation of your tooth - that's it, no special physical qualities.

Excellent explanation, thanks for that.

I am however somewhat perplexed in that I thought a build-up was to reconstruct portions of missing tooth so it could be properly crowned. Modern technology involves incredibly durable build-up materials (so I'm told). In my mind I picture leaving the buccal side largely in tact as an underlying lateral sheer stabilizer, with the lingual side built up, so under a gold crown it shouldn't fail from lateral forces. And the crown would have friction from buccal tooth material on one side, with build-up material on the lingual to hold it in place. Again, this is me knowing nothing but generalities, but hopefully I explained that adequately. I do understand the notion of wanting the best adhesion possible, but am still not quite following why a gold crown would be more likely to fail in this scenario than other teeth I've cracked above the gumline. Unless a build-up does not provide sufficient tooth substitute for friction to hold a crown in place over the longer haul. Is that basically the concern in my case with using a crown other than a silica-based or resin ceramic crown?

 

[MattKW]

A gold crown made for tooth fractures above the gumline can be great. You need a fair amount of tooth all around to take the lateral forces of chewing, because there will be no bonding. Yes, if there's not a lot of tooth structure above the gum you can compensate by building up a composite core, but the main strength for an unbonded gold comes from whatever natural tooth you can use. In your case, you have NO natural tooth wall on the lingual side.
If you did a core build-up before making this crown, the buildup would either be composite with pins(?) (bonded) or amalgam with pins (unbonded). Pins won't really help in such a big fracture, so I wouldn't bother.
So, you might do a bonded composite core, then shape it to take a gold crown. The strength still depends on the bonding of the core - no advantage, just an unnecessary step.
You are no better off (and arguably slightly worse off) than simply using a solid bonded ceramic, a lab-made bonded composite crown, or a CEREC bonded resin crown.
So much depends on a good bond across that large fractured area. There's still a moderate risk that it will all fail. If this tooth was already dead and root-filled, I would extract and do an implant. You have an option to try and save the tooth only because it is still alive.

 

[SonicExplorer]

A gold crown made for tooth fractures above the gumline can be great. You need a fair amount of tooth all around to take the lateral forces of chewing, because there will be no bonding. Yes, if there's not a lot of tooth structure above the gum you can compensate by building up a composite core, but the main strength for an unbonded gold comes from whatever natural tooth you can use. In your case, you have NO natural tooth wall on the lingual side.
If you did a core build-up before making this crown, the buildup would either be composite with pins(?) (bonded) or amalgam with pins (unbonded). Pins won't really help in such a big fracture, so I wouldn't bother.
So, you might do a bonded composite core, then shape it to take a gold crown. The strength still depends on the bonding of the core - no advantage, just an unnecessary step.
You are no better off (and arguably slightly worse off) than simply using a solid bonded ceramic, a lab-made bonded composite crown, or a CEREC bonded resin crown.
So much depends on a good bond across that large fractured area. There's still a moderate risk that it will all fail. If this tooth was already dead and root-filled, I would extract and do an implant. You have an option to try and save the tooth only because it is still alive.

All I can share about the buildup is they use something (I think from different materials from a dual sided syringe?) and then used a UV light to harden it almost instantly. I recall they said the new bonding materials are so strong they can almost act as a tooth by themselves. But I suppose that doesn't necessarily mean it bonds well to the tooth...which is what I think you are trying to convey as one of the main issues with considering the gold crown vs. another type that is better suited for bonding in my case.

Thank you (and Dr. M) for sharing your excellent knowledge and insight. It is tremendously helpful, and I'm sure it will help other forum members who read this discussion in the future.

Sonic

 

[SonicExplorer]

Correction, meant to type "I recall they said the new buildup materials are so strong they can almost act as a tooth by themselves."

 

[MattKW]

No problem. It just seems like doubling-up unnecessarily to bond the crown to a bonded core. It's really just the bond of the core, or the bond of a ceramic crown directly to the tooth, that will ultimately determine your chances. And keep the cusps flat-ish.