Here is a single arch case, where if I had done this without extractions, the patient would have hated the result!
So here is my thinking, and treatment planning.
Great, so lets do the planning:
On the right, she is 1/2 unit class 2 (canine), almost class 1 molars, and on the left, 1/2 unit class 2 canine, and again only very mild class 3 on the molar.
The overjet and overbite are normal, and the inclination of the incisors is about normal, so although there is upper arch crowding, I definitely don’t want to round out the incisors, as this will increase overjet, and procline the teeth – a look that very few patients like!
From the occlusal, we can see about 3-4mm of crowding, so if we were to just put a brace on, then the incisors would just tip forward, proclining them, leaving me with an unhappy patient!
One common goal for treating my patients is to get the canines into Class 1 occlusion, that way I know the overjet is going to be reasonable, in this case, the overbite is normal.
On the right side, the existing space is not where I want it.
But as there is space, it would be silly to extract a tooth to make more space!
The issue is that being so far back, this space will close quickly, without relieving the crowding at the front – which is where we really need the space.
To help with this issue, we need to reinforce anchorage (stop the 6 moving forward).
On the left, there is no space at all! The canine needs to move half a unit distal, so its reasonable to consider an extraction here. The 4 is already filled (and the filling looks terrible!), so this is my choice!
The canine will move 1/2 unit back, and the premolars and molars will come forward to close the space (before de-bond).
After bond up and XLA
To reinforce the anchorage on the right side, I have done two things:
- Bonded up the 7
- Placed a TAD for direct anchorage
I bonded the 7, so I can start pulling from the 7-4, and as the molars have a greater root surface, and two molars are better than one, I would hope that there is more premolar movement than unwanted molar movement.
To be double sure, I linked the TAD to the 6 bracket. This would hopefully link the 6 to bone, which in theory will not move at all!
On the left side, I just bonded up to the 7 – on this side, I actually want to burn off a little anchorage by bringing the molars forward.
This is a few appointments in and you can see that (even in the previous shots) the incisors have tipped forward! They are now proclined – and the patient hates this look!
This is what the patient would have been left with if I had tried this all non extraction. I could have done some IPR to bring them back a little, but I think you would need to heavily IPR them to bring them back to a decent inclination!
You can also see that once the premolars are back, and the left canine is back, I have used a long tie to lock them all together, and powerchain to tip back the incisors.
This kind of treatment, where you tip the incisors forward, then back is called round tripping.
The finished case
In the end, all the gaps were closed, and the patient is really happy with the results.
There are a few areas that I think it could have been improved:
- I could have done some IPR to reduce the black triangles.
- I could have used a laser to make the gingival contour more symmetrical.
- Whitening would have improved things too.
Did the TAD make a difference?!?
If we look at the molar, then its come forward by about 1/2 a unit. The premolars have come back a little, but at the canine, we have hardly gained any space!
In this case, I didn’t need that much space, so I think I got away with it!
There are ways to distalize the canine from here, but it gets a bit complex, and it was unneeded in this case.
Looking back, there are other ways to reinforce anchorage – and in this case, a Nance appliance would have worked great.
The nance appliance will hold the molars back, by using the hard palate. I think this would have been better in this case.
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