Closing Black Triangles Simply, Predictably and Profitably
Posted on
Jul 19, 2024
Is there anything more satisfying than putting the finishing touches on a clear aligner case in a single visit using direct composite?
While achieving Instagram-esque results with direct composite may seem reserved for your favourite internet dentists, it is certainly within the reach of the general dentist and the aligner enthusiast. In other words, it’s well within your reach!
All you need is the right techniques and a dash of practice.
Here’s a technical guide to closing black triangles like a pro following aligner treatment. It’s the best way I’ve found so far, and is guaranteed to bring both you and your patient the joy that comes with a completed smile transformation.
💡 Want To Learn More?
If you’d like to learn more applications and top clinical tips you can apply in practice, then you can book a zero-cost 60 minute online CPD session with me at www.drecomposite.com
Just click FREE CPD and choose a lunchtime or evening that works best for you. A CPD certificate will be awarded upon completion and, who knows, it just may change your life!
Key Technical Terms in this Article
Perio-Restorative Interface
The periodontal-restorative interface is that between the tooth and the marginal gingival tissues. Any disruption to the area is likely to lead to inflammation. Any inflammation in this area is likely to compromise the outcome of the restorative procedure. Understanding the relationship between this interface will lead to improved predictability and outcomes of restorative treatment. 1
Emergence Profile
The emergence profile—defined as “the contour of a tooth, restoration, or implant where it emerges from the gingiva.”2
Greater Curve Matrix System
The world's first and only universal matrix system. Allowing clinicians to treat any class cavity and any direct restorative challenge, with or without conventional rubber dam. From subgingival cavities to black triangle, diastema and composite veneers this is my go-to system for every case I treat.
References
- https://www.reenawadia.com/10-key-points-on-the-perio-restorative-interface-with-miss-ulpee-darbar/
- https://www.aegisdentalnetwork.com/idt/2018/01/the-importance-of-the-emergence-profile-and-tissue-cast
Black Triangle Formation
It’s a universal experience, right? We’re progressing through a course of aligner treatment and gradually notice dreaded black triangles - that definitely weren’t there at the start - forming along the way…
To make things worse, your patient then points them out too, causing your blood pressure to rise a few ticks!
However, this is part of the game of moving teeth and, as long as we can solve it, should not be a cause for concern. As always solid communication before treatment begins is key.
So, what causes Black Triangles to Form?
We can all recognise the signs of an aligner case where there’s a major black triangle risk. The most obvious sign is a patient with triangle-shaped teeth.
To make things worse, we also know it's going to be stressful to finish these cases, as getting the proportions right isn’t as straightforward, with composite usually being required on the mesial and distal sides.
A common approach involves treating each side separately which adds time to the procedure and depending on pricing structure can really eat into profitability. (I’m obsessed with all things efficiency and prefer to avoid multi-step processes when possible, as I’ll come to.)
Challenges when Treating Black Triangles
When treating black triangles we are, by definition, working at the perio-restorative interface and, as a result, moisture control is a major concern. Contaminated composite will not only debond but will stain prematurely. This is certainly not what we want when treating the most aesthetically minded patients of all!
Rubber dam, floss ties or even subgingival clamps are recommended by many, however these methods can be time-consuming, fiddly and, not to mention, stressful. They definitely aren’t my favourite isolation methods for anteriors.
Emergence Profiles
I still see some dentists using straight mylar strips and wedges to close black triangles. In my opinion this is aesthetic suicide. Straight strips cannot produce anatomically-shaped emergence profiles and trying to seal your strip / matrix of choice with a wedge can, in the process, produce a black triangle in and of itself. This is obviously not our objective.
Commonly Taught Methods
Some of the most popular methods that are taught to postgraduates to close black triangles include using Garrison Varistrips or Bioclear Matrices. I have never enjoyed these solutions as they lack stability, and I’d need to tie up one of my hands just to support a delicate strip, making the whole procedure unnecessarily cumbersome.
The other thing I also don’t enjoy about these methods is the fact that mylar and clear plastic are rather soft, and so is composite, making it unpredictable to pack without producing voids, at least in my hands. If we have voids in our composite, caries will develop over time and will often masquerade as minor staining… no bueno:
For the practice owners and freelance clinicians reading this, do also check out the cost of Varistrips and Bioclear, then add in the accessories including a rubber dam sheet, and you’ll see the costs that will accumulate over the financial year!
Overhangs / Ledges / Gingival Inflammation
During my day-to-day practice I see patients where composite has already been placed freehand or using PTFE as a separator producing overhangs, ledges and a boat load of gingival inflammation.
This is not easy to rectify as removing composite from below the gum line is something we have to do blind (most of us will not be raising flaps to treat this) and without damaging the root. This is no fun for us, or the patient, especially when they come back upset and with angry gum. In my opinion, it is critical to avoid this happening during composite placement. (Don’t worry I’m getting to how we can completely swerve this risk!)
Iatrogenic Damage From IPR (Interproximal Reduction)
It’s also not uncommon to inadvertently cause iatrogenic damage when performing IPR. Patients may report sensitivity from the area immediately or - once the teeth are aligned and it becomes more obvious - point it out to us later on. Not to stress - the method I’ll share makes restoring this issue pretty straight forward too.
Closing Black Triangles and Diastema Successfully: My Go-To Solution For Black Triangles / Diastema
Closure: The Greater Curve Matrix System
The Greater Curve Matrix System features a brass range. Brass behaves differently from the stainless steel range in that it doesn’t bounce back. This means you can burnish shapes and contours which stay, producing straightforward, beautiful black triangles and diastema closure. Not to mention, with a little bit of training, the closure we can achieve is complete:
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Brass To The Rescue
In this shot you can see a Greater Curve Brass U band in place and the black triangle/diastema space completely closed with a simple burnish. The design and mode of action means it's virtually impossible to get composite to irritate the soft tissue.
As mentioned, I love efficiency, and so the fact that I can treat the mesial and distal at the same time, rather than have to do two separate procedures, is the cherry on the top of an already well-iced cake!
I also love the fact that the Greater Curve Matrix is stable and does not require me to hold or support it with my other hand. This means I’m free to use my mirror to observe that oh-so-important incisal view, and focus on the composite placement.
Pro Tip: I ask my assistant to hold a photography mirror when treating multiple units to give me a wider field of view, orientation, and to keep my placement nice and proportional.
Void Free Composites
The major benefit of using a metal matrix, is that the composite can be well-condensed interproximally, preventing voids, as opposed to packing against soft materials like PTFE or mylar:
Isolation
The Greater Curve Matrix System allows for standalone isolation at the matrix level or enhanced rubber dam isolation. It differs from traditional matrices, which rely on wedging to achieve a seal and instead tightens at the neck of the tooth, preventing the ingress of blood, saliva or gingival crevicular fluid.
As we all know, the seal is the deal, and you can observe a clean dry working field in the shot below where I am repairing some post aligner iatrogenic IPR damage that the patient was unhappy about. In my experience, if we can solve a patient's problem, typically their ill feeling also disappears.
💡 Want To Learn More?
If you’d like to learn more applications and top clinical tips you can apply in practice, then you can book a zero-cost 60 minute online CPD session with me at www.drecomposite.com
Just click FREE CPD and choose a lunchtime or evening that works best for you. A CPD certificate will be awarded upon completion and, who knows, it just may change your life!
Beyond Black Triangles...
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