The Endo Fix

Tag: Custom Resin Matrix

Survivorship Bias

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From Grok: “Survivorship bias is a cognitive bias that occurs when we focus only on the “survivors” (the successful people, things, or outcomes that made it through a selection process) while ignoring those that didn’t survive or weren’t visible. This leads to overly optimistic or skewed conclusions because the full picture is incomplete.”

 Plus from Wiki: “It can also lead to the false belief that the successes in a group have some special property, rather than just a coincidence, as in correlation “proves” causality.”

The only way to measure outcomes is to measure them, and follow-ups improve outcomes, but be careful in ascribing certain successes to particular processes and procedures. I gave this tooth a poor long term prognosis, and yet here we are 8 years down the road and it’s looking good. Meanwhile, on the same patient, I’ve treated 8 other teeth since. So, low prognosis & high hostility, successful outcome, so far. Through that lens it’s difficult to say that this isn’t a gold standard of management. Of course there are clinicians that can post similar cases from their own stream using plastic which is undoubtedly easier to do. So, here I’m left with “is it worth the considerable extra effort to treat with silver” or do the easier single pour?

So, when this patient walks in with cancer, can’t get teeth out, comorbidities yada, yada, yada. Clearly a high hostility index. What do we do? There’s always uncertainty, but in the most hostile environments this kind of management works best most of the time. That’s unfortunate for me, because this takes significantly more time and effort. Thank God for the assistant side, without it, this is simply not feasible. Thus the recall woes. All three required custom resin matrices like pictured below.

Custom Resin Matrix- 9 Years Ago…

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Suffolk endodontist

This is the same patient as the prior post but contralateral side. She had extensive decay under the existing crown which didn’t leave much to work with. It was a pretty tough case to band and I couldn’t get it to stay on so I created a custom resin matrix out of Opaldam. Things still look good for this beat up tooth for almost a decade.

Custom Resin Matrix

Weekly Fix
su
Suflolk Endodontist

Terminal teeth are tough to band and keep rubber dam isolation. So we came up with an alternative- the custom resin matrix. Using green opaldam we make a custom matrix to pack amalgam with or place a controlled field resin. Often we use the technique subgingivaly on bone. For first iterations we used white Opaldam but found it hard to discern on bone. The green is easier to see and thus remove. Waiting 5 minutes or so for the amalgam to harden makes the green matrix easier to remove

Frustum Retention

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Keeping the preparation conservative even in the last 2-3 mm helps in retaining the core. The shape of the access here is a frustum, or pyramid with the tip cut off. This providees a macro-retentive feature for the core. Terminal teeth can be difficult to place a band on so we used a custom resin matrix.

Deep Margin Management

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hampton roads endodontist

Suffolk Endodontist

 

Deep caries and the resulting deep margins can be a restorative problem especially when the patient has a history of interproximal caries or a “high caries hostility index”. Generally speaking it’s better to have a crown that fits and fits on a meticulously placed deep restoration than a crown that doesn’t fit. And when the margin is very deep, then that is when a poorly prepared and poorly captured margin is most likely. An alternative is DME or deep margin elevation. Dentists have unintentionally placed margins on amalgam for decades with success. It’s likely that the outcomes will be even more favorable when done intentionally under controlled circumstances, under magnification and with no overhangs. Attached is a 7 year outcome with the crown placed on amalgam. Also attached are two very long term outcomes. When placing margins on restorative material, it is probably best to choose amalgam over composite as it does not rely on bonding which is poor under such conditions. It’s also advisable to evaluate the emergence profile of the tooth, it’s contact with adjacent teeth, and potential plunger cusps that led to the problem to begin with. Managing these variable can prevent food impaction and decrease the probability of failure to recurrent caries.

Bridge Retreatment

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Suffolk Endodontist

 

Suffolk Endodontst

The patient presented with pain on the distal abutment of the bridge. Clinical examination revealed caries and that the bridge was loose on the mesial abutment. The patient wasn’t interested in implant therapy due to a prior bad experience and chose to have the bridge remade. The premolar was retreated (Thermafill carrier removed with hedstroms) and the molar treated endodontically. Due to the wide short chamber present on the molar we chose to make a dual access leaving a dentin truss for support. The premolar was restored with a fiber post for rehabilitation purposes. We opted to use custom resin matrices for restorative purposes. The 1 year followup shows a good fitting bridge, and a functional asymptomatic restoration.