The Endo Fix

Category: Daily Fix

Survivorship Bias

Daily Fix

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.

Embrasure Space Recapture

Daily Fix, Tips, Tricks, and Hacks

The embrasure. I don’t think most clinicians give enough thought to the embrasure. It’s the contact in three dimensions. It is dictated often by tooth position and or restorative. As long as there is sufficient embrasure space, the contact can be elongated, broadened, and shifted bucco-lingually. In order for both teeth to have convex curvatures an embrasure space of 2-3mm is necessary. In some instances root proximity sets the tooth up for failure as a proper embrasure is almost naturally impossible. In many instances the embrasures provided by implants are dangerous for adjacent teeth.

The bottom line is that good embrasures are important for proper function and longevity. And in some instances the space required for a proper embrasure has been lost.

Here’s a recent case where the embrasure space is negative, probably negative 1-2mm. Gingival ingrowth can be seen.

The caries was removed and a band placed. From the occlusal, we can seet the proximal convexity of the distal tooth was over the distal cavosurface. Fuji core is great in this indication. It sets completely and immediately, and comes in a blue color that’s clearly visible but not ridiculous. The canals were instrumented medicated and the access closed with cavit. Then an orthodontic spacer was flossed into place.

After 3-4 weeks, the patient returned. We had recaptured 2-3mm of space, which is typical. The endodontics was finished, an amalgam core was placed, and after it had set we placed another spacer to recapture another couple of mm’s.

I think this really stacks the deck for the restorative dentist, and as such exemplifies Restoratively Driven Endodontics.

Here was an early case from 14 years ago. We used Luxacore blue back then. I think the Fuji core is an upgrade. Might be the first one performed, at least by me.

Here’s another embrasure space recapture from almost 10 years ago. You can see in the upper right picture how much space was regained from the spacer.

It may not get a lot of play, but I think it’s a nice one to have in the bag of tricks.

Horizontal Root Fracture

Daily Fix

This seems to be fairly predictable of this case type. Stabilize it. Monitor it. Watch it pulp canal obliterate (PCO). And the root tip kinda sails off into the sunset. Based on those that I’ve seen, a horizontal root fracture like this doesn’t have a terrible prognosis as long as it’s managed correctly. Meaning the doc keeps his handpiece holstered.

Here’s a couple other older cases with the same progression. The increased density caused by PCO can cause some color changes, not to be confused with a necrotic tooth. No intervention is necessary. If desired, internal bleaching without endodontic therapy can be offered, which of course carries it’s own risks, benefits, and alternatives.

Some of these can be observed in the wild 30 years after the fact.

Blue Light Special

Daily Fix

The intersection of scopes, filters, composite, and light can lead to some confusion and possibly unsafe clinical habits. So lets get the whole story straight and make sure our working habits are healthy as well as productive.

Light cure composites set when they are exposed to a light energy at a set wavelength of light. The composite has a photo-initiator called camphorquinone and an accelerator. The activator present in light activated composite is diethyl-amino-ethyl-methacrylate (amine) or diketone. They interact when exposed to light at wavelength of 400-500 nm, i.e, blue region of the visible light spectrum and cause the composite to set.

Sunlight, ambient light, and all other white light have the entire spectrum. So in the operatory, the ambient light will have enough blue light to make composite eventually cure. And your scope light with all its fabulous power will totally cook your composite. Additionally, the blue light with its low wavelength and high energy has the potential to cause harm to your eyes. Macular degeneration, retinal problems, and possibly cataracts are on the table eye damage wise. In addition, blue light is believed to affect mood and sleep among other things. Fortunately, there are filters that filter out the blue light.

Looking at the color wheel which represents the colors (ROYGBIV) and their opposites, you can see the opposite of blue is orange. So these orange filters will filter out the blue light.

Which comes in super handy when working under the scope doing composite work:

We do all our bonding using the orange filter in the scope. And here’s where some people get bamboozled.

Awash in orange light it’s easy to think that your scope filter is protecting you during the cure process.

Oh contraire monfraire!

If you were to remove the light from the back of the scope, and hit a cure, you’ll notice there is no difference whether the filter is applied or not.

The filter isn’t in the column at all. Its where the fiberoptic/liquid cable enters the back of the scope.

It’s this little guy here…

So when it’s time to cure, either look away out of the scope or don some protective eye wear.

In the case of performing a custom resin matrix, its eye wear for the both of us. Routine composite work, I usually just close my eyes till I hear the beep.

Dens Invaginatus

Daily Fix, Large Lesion

Sometimes the development of the tooth goes a little haywire and another tooth begins to develop within a tooth, but not completely. So we end up with this invagination leading to the pulp and sometimes it doesn’t completely close off. Such a situation set the pulp up for an early death as can be seen here by the lack of root development and divergent open apices. Here we have a a pretty large finding imaging wise and a swelling. We changed the calcium hydroxide medicine out over 5 months and ultimately filled the apical 5mm with MTA and then reinforced the rooth with a fiber post. At 4 years post op there appears to be complete radiographic clearing and retained radio-opacity from the calcium hydroxide.

Portal

Daily Fix

Amalgam is a great material because it’s not technique sensitive. When done well it stands up to quite a bit of abuse and hostility from the patient. Here we can see the whole distal dislodged. And while I can’t remember it ever happening to one of my buildups, I want to prevent it from happening. So I began, when reasonable making a portal that ties the distal component to the internal frustum core. A massive macromechanical retention feature. The result is this little triangle of tooth coronal to the circle in the second image. And yeah, I usually bond these big amalgams for belt suspenders as well as maybe some anti fracture attitude. The early portal cases naturally led to the double entry truss cases that followed.

Internal Approach

Daily Fix, Resorption

This tooth presented with inter-proximal external crestal resorption according to my resorption classification for clinicians. Usually I like to have an external surgical approach to ensure clean margins, manage the field, and work the appropriate matrix. However, an external approach here would have left one hell of a periodontal problem and lots of bone destruction. So, we worked it out internally. Ultimately, glass ionomer was used as the restorative choice here. On short termish recall, the perio tissues look great- 3mm probings all around and no bleeding on probing. So far so good, no resorptive recurrence.

Titanium Decision Making

Daily Fix

I’m not really even going to get into the decision making generally speaking with regard to the bridgework that cantilevers with two premolars off the back end of the canine, but doesn’t connect to the molar. But, I’m thinking that such a person used similar thinking with regard to their post choice. Radiographically this is either fiber or titanium. On access I confirmed titanium and then closed up shop and reappointed for the surgery. Unlike fiber, they can’t be drilled out, and unlike other metal posts they don’t vibrate out well, so the result of removal is coronal carnage. Thus the decision to whack.

Similar thinking led me down the road on this recall from a different patient this week. Bone fill at 6 months looks great with my eyes.

Lets leave the titanium to the implant specialists.