i actually did a double take, as i thought the radiopaque material was the metal coping. but that’s an all-porcelain crown. looks like ti-core material, from my experience.

what may have happened was that the core material was subginigival at the distal on this patient and the dentist may have been afraid to take the prep too far subgingially due to bleeding, fear of prepping too close to crestal bone, who knows. just some speculation. looks like it’s sealed from the bitewing and a lot of the core materials used do contain fluoride, so while it’s not ideal, i wouldn’t doom it to hell and just watch it over time.

on another note, i’m still on the fence about all porcelain restorations on molars – they are still relatively new and i’m not sure about the longevity of zirconia copings over a 10 year period. i just can’t bring myself to do one just yet. call me old school, but i still love full gold crowns. kind to the gingiva, easy to prepare, no fracturing. not as pretty, but lasts a long time.

it seems to me that if the doctor had prepped beyond the core buildup to end the margin on natural tooth there would have been plenty of biologic width to support a crown without the need for crown lengthening – but you can’t tell without probing depths, either.

as for the short root trunk, i think if the mesial roots have good support, the minimal amount of bone that would need to be removed for crown lenghtening on the distal would not have a negative effect on the tooth’s perio status. a periodontist who would see that case would (should) let the referring DDS know if he/she thought it wasn’t the best treatment. i actually just sent out a case not too long ago like that. the distal root where the CCL was going to be performed was very short, but there was such great support on the mesial that even the periodontist who performed the surgery said that it would be a successful case. i think the prognosis is less favorable for single-rooted teeth as opposed to multi-rooted molars. but i can understand your trepidation.

then again, there’s always the option of extraction and implant for this particular tooth. how bad is the pathology at the apex? what’s the endo prognosis after tretreat?

actually, good point about the furcation of molars. but when speaking strictly in terms of mobility and crown to root ratio, i think interproximal bone removal of molars is pretty safe. i did my first CCL procedures when i was in dental school, one on a canine and one on an upper second premolar. both teeth had shorter roots, barely a 1:1 crown to root ratio, and 1 degree mobility after the surgery and 6 week healing period. so in terms of shorter roots, i think there’s a little more leeway with molars than single rooted teeth because you have other roots for added support.

i personally haven’t seen many CCL cases that are performed on buccal and lingual surfaces, most of the decay patterns i see originate at the interproximal and that’s where i found i run into the most problems when prepping teeth with extensive caries. if a tooth is fractured or has extensive caries below the gum line on the buccal and it looks like the roots are very divergent or the furcation is located more coronally and probing is tight there, i usually recommened extraction and implant. if the patient is insistent on saving the tooth, i send the patient to the periodontist with the tooth prepped to around where i want my margins to be with the caveat that it might not have the best prognosis. but that has very rarely happened to me.

i guess it depends on the tooth, depends on the patient, depends on the circumstances. i’ve taken preps pretty far sub-g with no subsequent perio problems (checked at recalls, etc). this particular tooth i might have taken the prep sub g, put the patient in a really well-fitting temp and reevaluated in 2-3 weeks. gingiva are pretty resilient like that.

A lot of my referring dentists seem scared to suggest crown lengthening to their patients because they are probably afraid that the extra cost would deter the patient from going ahead with the crown.

I end up suggesting it for the first time in these cases. I’ll often refuse to do the endo unless crown lengthening is planned. That’s a defensive practise because once the restoration leaks and the endo fails, it obviously becomes my fault that the tooth has become problematic again. Patients don’t know any better and generally trust their regular dentist more than me whom they’ve only seen a couple of times.