How much tooth is needed for a crown?

[jamesmarco]

Hello

About 5 months I had a large filling (LL5). My dentist preferred to fill rather than crown to let the nerve settle down. The filling failed and there is now only a 2-3mm rim of tooth showing above my gumline. The rim however only goes round 75% of my tooth, the remaining 25% of the rim (at the back) is about level with my gumline. My tooth now looks like a crater with this 2-3mm horseshoe like rim. There is no decay and the root is excellent. Is there sufficient tooth to crown? I dont want to waste my money on a crown if there is not sufficent support. But I do not fancy an extraction (because of the risk of drifting) or a bridge. Hence that would only leave an implant but that would be very expensive.

Many thanks in advance.

[prosman]

you may need crown lengthening surgery, but it should be possible

[jamesmarco]

Many thanks for your reply Prosman but cutting away my jawbone to lengthen my tooth sounds painful

Do you think the 2-3mm rim would be insufficient to support the crown as it stands? Even if it was filled and pinned? I realise there should be a 2mm ferrule to give lateral support but I wondered if pinning and filling would help? Or do you think it would be a waste of time crowning as it is?

Cheers

[prosman]

Pinned fillings do not help keep crowns on sorry. Anyone who tells you different hasn't read all the literature.
There are ways to go about crowning this tooth with out crown lengthening but they are not ideal and I would really need to have more info before I could suggest if they are possible.

[Dr Sepehrara]

The crown lengthening procedure may not require bone removal, each case is different. Even if it does, it is a simple procedure .... if carried out correctly.

[davidbloom]

The literature tells us that we need a rim (ferrulle) of 2mm all the way
round the tooth for a post and crown to be successful. I am assuming
because of the small amount of tooth that the tooth is root treated. It
may be possible to remove a little gum to allow this but this will
depend on the position of the supporting bone - there needs to be a 2-3
MM gap (biological width) between the edge of the bone and the edge of
the gum for health. If the tooth has not been root treated careful
preparation of a 2mm parallel surface along with retention grooves
should be enough to retain a crown.

If neither of these are possible I feel an implant would be your best
option long-term

Regards

David Bloom
Past President BACD
Accredited member BACD

cid:[email protected]

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