High mandibular plane + overbite - what can I do?

[Sidney]

I'm looking for a way to correct the overly high angle of my mandible. If you don't know what I mean by this, imagine a person opening their mouth so that the chin would not point forward but into the floor, that's how my lower jaw is at rest (the bite is closed, though).

This gives me quite a weak jawline a long face and leaves me with no chin.

This kind of skeletal structure, I think, is usally seen in open bite cases and is rectified, among other methods, by intruding the molars, thus letting the mandible autorotate upwards, closing the bite, shortening the face and strenghtening the jawline and chin.

However, in my case, not only do I not have an open bite but I have an overbite so my mandible has no space to rotate into.

Can anything be done in my case?

My upper incisors are retroclined, would proclining them and then moving the mandible forward into the space created (some space was alread there because I have minor overjet) cause the back part of the mandible to drop down? If not is there some other way to rotate the back of the mandible downward?

I don't know whether this is significant so I'll mention it just in case: I have narrow arches with the mandibular molars tipping toward the tongue.

Any help is greatly appreciated.

[fosterp]

I have the "exact" same problem as you. A vertical excess with an overbite. And unfortunately my ortho said hes going to correct the overbite by protruding the posterior teeth, which is only going to exaggerate my lip incompetence and long face. I am going to talk to him about this next adjustment though and hope we can change the plan and intrude my teeth instead. I have seen plenty of cases where they correct the overbite by intruding the upper incisors. I've seen a lot written against intruding the lower incisors but I have also seen that it can still be effective as well if the patient is already an adult.

Intruding teeth it seems is quite a bit more difficult than extruding it seems. The oldest method is by using headgear, recently TADs do the job as well, but I've seen some cases where they use special kind of arches that are supposed to do it as well.

But in theory, intruding the posterior teeth would in turn rotate your mandible up and foward, which I believe is what you would desire, but it also presents the problem that such movement exaggerates an overbite, so the anterior teeth would need to be intruded as well if not more.

[Sidney]

I have the "exact" same problem as you. A vertical excess with an overbite. And unfortunately my ortho said hes going to correct the overbite by protruding the posterior teeth, which is only going to exaggerate my lip incompetence and long face. I am going to talk to him about this next adjustment though and hope we can change the plan and intrude my teeth instead. I have seen plenty of cases where they correct the overbite by intruding the upper incisors. I've seen a lot written against intruding the lower incisors but I have also seen that it can still be effective as well if the patient is already an adult.

Intruding teeth it seems is quite a bit more difficult than extruding it seems. The oldest method is by using headgear, recently TADs do the job as well, but I've seen some cases where they use special kind of arches that are supposed to do it as well.

But in theory, intruding the posterior teeth would in turn rotate your mandible up and foward, which I believe is what you would desire, but it also presents the problem that such movement exaggerates an overbite, so the anterior teeth would need to be intruded as well if not more.

How much overjet do you have?

I'm not even going to fix my overbite because it doesn't bother me and, as you said, if I were to fix it (except for intruding the incisors) it would lenghten my face.

I still have a lot of research to do, but, obviously, the only way to fix our problem (mandibular angle, that is), save for surgery, is to increase the length of the posterior lower face - to make the back part of the mandible go downward.

As I said, I have to research this further, but it seems that this would be done by making the condyles grow. Growth of condyles pushes the mandible forward and, I think, upward. Maybe, seeing how our mandibles can't rotate upwards, this would result in the back part rotating downwards (which is what we want).

Furthermore, say you don't fix the overbite, the mandible can't move forward, so maybe, all that "slack" would go into rotating the back part downward, thus reducing the angle.

The herbst appliance has been shown to cause growth of condyles in adults.

Again, all of this has to be further researched.

Do of any other possible way to reduce the angle? If you're interested in researching this we should pool our resources.

[fosterp]

Well you seem to know a lot more than I do since I don't know what half of the terms you just used mean. I don't think I really have an overjet, but the way my front teeth are positioned make it kind of hard to tell what their problem is since they are crossed over each other. In fact, looking at one side of my bite its almost as if you see the curve of spree showing an almost openbite tendency, while on the other side showing an overbite.Theres a link at the bottom of my post that shows my braces story with pictures of progress in 5 months. One thing to note though is the way my mouth is positioned that makes it seem like my lower jaw has moved down considerably but this is not accurate, since I had bite turbos at the beginning, and then since having those removed my back teeth aren't touching for some reason, probably owing to the movement of my premolars.

My case is kind of unique and not so straightforward. My biggest problem I think is probably the asymmetry of my bite that might make it seem like I have some of the traditional problems when I don't. However I do have the problem you describe of excessive vertical growth, and my uppers sort of tip inward a bit all around causing a crossbite on one side. As a result, I have a bit of lip incompetence, and sort of a crappy jawline.

I've done a lot of reading like you though and from what I have seen theres only two ways to autorotate the mandible - increasing the dental clearance by intrusion of posteriors, or reducing the clearance by extruding posteriors(what we won't want). I have seen the first done in a lot of cases with TADs and some other fancy tricks, but I have yet to see intrusion of the entire upper arch, which is what we would need since rotating the mandible up and forward would only increase the overbite. Theres also the possibility of maxillary impaction lefort, but that would seem a bit extreme given it would only be done for purely aesthetic reasons (though it would make overbite correction easy), and its not a simple surgery or recovery.

I do think though at least in my case that the restricted arches and tipping inward of teeth may be part to blame of my vertical excess, and expansion of the arches and aligning may help at least a little in resolving my problems. Its a big waiting process though, and I'm ready to finally just drill my ortho about whats really going to happen since I am tired of speculating.

[Sidney]

Sorry for the late reply, fosterp, had some internet problems.

and my uppers sort of tip inward a bit all around causing a crossbite on one side

How do the retroclined uppers cause crossbite? You mean the mandible goes to the side because of lack of space because of the retroclination?

I do think though at least in my case that the restricted arches and tipping inward of teeth may be part to blame of my vertical excess, and expansion of the arches and aligning may help at least a little in resolving my problems.

Why do you think that the tipping inward and narrow arches are to blame for the vertical excess? Aren't the arches just a horizontal thing? The only way I see them having any impact is that expansion might make your face wider, thus balancing it out, counteracting the length.

The tipping of inwards, as I see it (and I'm not sure on any of this), could only make your mandible go back, which would actually reduce the length, if anything.

[Sidney]

I have yet to see intrusion of the entire upper arch, which is what we would need since rotating the mandible up and forward would only increase the overbite.

How do you figure intrusion of the arch would help? Wouldn't that just bring you into edge to edge occlusion (that's when the incisors meet edge to edge) which would further rotate the mandible downward? Or if you were to intrude just a bit, you'd still get mandibular rotation and increase in overbite.

I also have to caution you that if you are going to have your upper arch expanded that this sometimes (maybe all of the time, maybe some of the time, I'm not sure on this) leads to the maxilla going down a bit, so it might increase your facial length. This is prevented with headgear that pulls your chin up, preventing the maxilla from going down.

Also, you should read up on what kind of expanders cause just dental and which also cause skeletal expansion. If you can get skeletal expansion that might widen your face, counteracting the length.

If you're going to research this, you should be ready for contradictory information and a lot of doctors saying skeletal expansion can't be achieved in adults, but don't be discuraged, it's not true.

[fosterp]

I think you are having a lot of confusion with terminology. When I say uppers tip inward I am talking about my upper posterior teeth on the side with the crossbite. They tip inwards - i don't know if that is the cause of the crossbite or a result of the crossbite, but elastics tipped them outwards and tipped the lowers inwards which corrected the crossbite. The tipping of posterior teeth inward could lend to increase the facial height because if you imagine a cube sitting flat has a certain height, and then if you tip the cube to one side, one corner of the cube will raise up while the other lowers.

And when one refers to intrusion/impaction or extrusion, that is in reference to vertical movement. If you have a lefort maxillary "impaction" that means they cut your bone, shave off some mm of bone, and then reposition. This moves the bone vertically upwards, and in response it reduces gummy smile/lip incompetence because it allows the mandible to autorotate in a counterclockwise fashion.

Intruding teeth is in reference to the vertical component as well. Intruding with TADs or intrusion archwires basically attempts to push the teeth back into the gums, increasing the clearance. This is what they commonly do for non surgical treatments of open bite cases. Its also done to treat overbites by intruding the anterior teeth. However in our case, in order to both reduce facial height and reduce overbite, "all" of the teeth would need to be intruded.

[Sidney]

I think you are having a lot of confusion with terminology. When I say uppers tip inward I am talking about my upper posterior teeth on the side with the crossbite.

Oh, I see, I thought you were referring to upper incisors.

They tip inwards - i don't know if that is the cause of the crossbite or a result of the crossbite, but elastics tipped them outwards and tipped the lowers inwards which corrected the crossbite.

So the lowers were tipped outwards?

The tipping of posterior teeth inward could lend to increase the facial height because if you imagine a cube sitting flat has a certain height, and then if you tip the cube to one side, one corner of the cube will raise up while the other lowers.

Good point, that hadn't occurred to me.

And when one refers to intrusion/impaction or extrusion, that is in reference to vertical movement. If you have a lefort maxillary "impaction" that means they cut your bone, shave off some mm of bone, and then reposition. This moves the bone vertically upwards, and in response it reduces gummy smile/lip incompetence because it allows the mandible to autorotate in a counterclockwise fashion.

Oh, when you said intrusion I thought you meant on the horizontal plane, my bad.

Intruding teeth is in reference to the vertical component as well. Intruding with TADs or intrusion archwires basically attempts to push the teeth back into the gums, increasing the clearance. This is what they commonly do for non surgical treatments of open bite cases. Its also done to treat overbites by intruding the anterior teeth. However in our case, in order to both reduce facial height and reduce overbite, "all" of the teeth would need to be intruded.

Have you ever heard of any cases where all the teeth were intruded?

[Sidney]

Hey, fosterp (and anyone else interested), check this out:

http://www.aoalab.com/index/cms-filesys ... etters.pdf

page 2, the study titled Removable Splint Herbst Treatment of
Anterior Disc Dislocation

They found increases in posterior facial height!

[fosterp]

I am not sure why you referred to that. The result of that appliance is not something you would want as increasing the posterior facial height would increase the anterior facial height and exaggerate your problem.

[Sidney]

I am not sure why you referred to that. The result of that appliance is not something you would want as increasing the posterior facial height would increase the anterior facial height and exaggerate your problem.

I read in a manual for the herbst appliance that the increases in anterior facial height that sometimes occur with it can be prevented by wearing some kind of a collar (aparently it's like the one you get when you hurt your neck) at sleep. Probably can be done with the high chin pull-up.

However, I'm not sure anymore that my particular problem is caused by a high angle. I have to analyze it more but it seems to be that my problem is mandibular width rather (or more so) than the angle.