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I feel it is necessary for people to understand how this is supposed to work.
I will first detail the premise behind the Biobloc, which is the origin of these methods of correction.
The preparation (or Stage 1) phase initially pushes both upper and lower incisors forward and up/down respectively. The upper incisors are tipped forward to correct the "indicator line" and the lower incisors are tipped forward to correct the "lower indicator line". Note that it is tipping and not pushing which we will discuss later.
The upper incisor movement is done to correct the position of the upper incisors relative to the cranial vault, and the lower incisors are done to help their position relative to the mandibular plane, in vertical growth cases both of these are increased.
The Stage 1 also expands the maxilla about 10mm, this is done to ensure tongue space and smile aesthetics but most importantly expansion of any kind causes reciprocal forward movement of the maxilla, due to the maxilla pressing up against the zygomatic buttress, separating cirum maxillary sutures. With 10mm of semi rapid expansion the maxilla moves 2-3mm forward, due to the slow enough rate for there to be added time tension at the circummaxillary sutures but fast enough to still act on the suture. This can cause a significant change in the mid facial contour. With rapid maxillary expansion this reciprocal forward movement halves, perhaps only 1-1.5mm.
Let's take this hypothetically vertical grown case for example:
Let's analyze the upper and lower indicator lines:
While we don't have numbers, we can see that they are both increased unoptimally. This must be corrected.
Shown in Red are the wires proclining teeth, shown in green are directions of movement and forces.
Now for the reciprocal forward maxillary movement from expansion of 2-3mm
Anyone would look at that compared to the beginning and say "wow you've ruined that face and the teeth you %$#$%@". "I'm gonna sue you".
But now the magic begins. Because the incisors are being supported in their forward position by the wires, now when a lip seal is present they can upright in their forward position with new alveolar bone growing around them. The incisors essentially rotate around the apex. See how the acute nasolabial angle becomes more normal and how the cephalometric Point A has remodeled forward.
Now look at all that space we have freed up for the mandible! The mandible must be rotated upward and postured forward. This must be done by molar intrusion and long term forward mandibular posture. The Stage 1 Appliance can intrude molars and sometimes extracts baby teeth early so that the closing effect can be achieved and the adult teeth can erupt in the upward position. Then the Stage 3 appliance makes sure the jaws are held together and forwards, which will remodel the condyle to that orientation eventually, it usually takes about a year.
Here is the molar intrusion.
Here is the mandible closing and moving forward.
After a few years, the ramus uprights too to maintain structural equilibrium and gives more room for posterior teeth (shown in picture), and there are also changes in the cranial base (not shown in picture).
Let's now overlay before and after (Red is before, Green is after):
It is a pretty good improvement. It resembles a moderate orthognathic surgery.
AGGA attempts to do all of this as well. However, AGGA's mechanism of action in my opinion is flawed. It pushes the teeth rather than tilting them and uses large and fast force. This causes root damage in the incisors, alveolar bone damage, and can lead to the loss of the teeth due to these forces often cutting off blood supply. Then, it attempts to upright these teeth in the forward position by using controlled arch braces rather than a lip seal, thereby using artificial forces rather than natural ones the bone can keep up with.
Here is a Gif I have compiled with each step for your viewing leisure.
Thats a very good explanation. Thanks you!
We did this information film about the basic concept of Orthotropics and how the Biobloc stage 1 appliance work on John Mews recent visit in Sweden. It complements well with your explanation. The explanation about Biobloc stage one appliance starts at around 18 minutes:
Your description sounds similar to what my provider is doing in my case. We spent about a year just with a splint, to get the mandible forward into its preferred resting place and hold it there. Then the first saggital upper appliance took about 8 months to close up the posterior open bite created by the mandibular repositioning. Next, we start lateral + saggital expansion.
Something else that others think AGGA fails at - many of the LVI docs like to use TENS devices to say they’re finding the physiological place for the mandible, but some people believe that the electrical stimulation does *not* penetrate the muscles deeply enough, or evenly, so it doesn’t find the right spot. But it had a certain “ooooh, science!” feeling for patients so that’s why they stick with it.