Is it possible to use TADs to intrude both molars and anterior teeth to reduce facial height in a normal bite, either on the upper jaw or lower jaw? What is the max amount of mm teeth can be intruded before problems occur? Is it possible to predict where facial height reduction occurs in particular, i.e. the chin for example?
The reason I ask is I had an open bite corrected by lower jaw surgery. It made my face longer and I'm very unhappy about it.
You have presented a very sophisticated question. What I write here are only my opinions based on very limited information. My comments should not be viewed as any form of diagnosis, definitive or otherwise, or any form of treatment recommendation. Indeed, in the ultimate analysis all final decisions, particularly clinical ones, should only be made by qualified doctors who have had a chance to see you in person and who have had an opportunity to take and analyze proper diagnostic records.recommendation. Indeed, in the ultimate analysis all final decisions, particularly clinical ones, should only be made by qualified doctors who have had a chance to see you in person and who have had an opportunity to take and analyze proper diagnostic records.
Okay… having said that… your questions focused on tooth intrusion and facial aesthetics. You asked:
“Is it possible to use TADs to intrude both molars and anterior teeth to reduce facial height in a normal bite, either on the upper jaw or lower jaw? “
It is possible to intrude teeth, including posterior molars and anterior incisors and canines, in either jaw. By so doing one affects the bite relationship and therefore to some extent the degree of closure between the upper and lower teeth and jaws. The more important question which you asked however is to what extent this can impact the appearance of a person’s “facial height”. Because your question is very sophisticated, I need to parse this down into several segments.
First let me say that we can view facial height in terms of how it appears to you as you look at yourself in the mirror. Orthodontists sometimes split this into upper and lower facial height when assessing the upper and lower jaw components. Very important however is the role of what is called “soft tissue drape” or the role of skin, fat muscle, and other soft tissue components which overlie the skeletal jaw components. It is not unusual to have radiographs ( X-rays ) reveal a strong upper vs. lower jaw skeletal discrepancy in a person, yet when you look at this person, things do not look that much at all out of proportion. This is known as soft tissue masking or camouflage. The point of all this Vic is to say that even if Tads were to significantly intrude various teeth so as to change the bite relationship, the practical observable change may be minimal.
This brings up a second point, namely how Orthodontists assess facial height in terms of actual physical appearance or based on radiographic measurements. A Cephalometric X-ray, also sometimes called a lateral Cephalometric X-ray, is a basically a radiographic image of the profile of a person’s head. I have attached an image below. Cephalometric measurements define both an anterior as well as a posterior facial height, and these measurements are used by teams of oral surgeons and orthodontists to plan surgical orthognathic procedures. In your case Vic, this is not what you are considering, but it does touch on the concept of “facial height”. Such orthognathic procedures are often done in cases of severe deviations from a normal bite or skeletal architecture. I have worked with many cleft palate patients for example.
Example of Cephalometic Radiograph see above.
You somewhat inferred that your bite is normal, so intrusion of teeth and or further significant orthognathic surgery might not be what is called for in your situation.
Again your specific question was:
“What is the max amount of mm teeth can be intruded before problems occur? Is it possible to predict where facial height reduction occurs in particular, i.e. the chin for example? “
The degree of intrusion for teeth depends on root size and morphology, degree of periodontal bone support surrounding the teeth, proximal contact points with the adjacent teeth in front and in back of the intruded tooth/teeth, etc. It has been my experience with TADS that the degree of intrusion has to be evaluated individually, and that the degree of intrusion is one or two millimeters at most. The practical impact on facial height likewise is likely to be minimal.
So Vic, the ultimate practical reason you wrote is the following:
“The reason I ask is I had an open bite corrected by lower jaw surgery. It made my face longer and I'm very unhappy about it. “
It is not clear whether you had an anterior or posterior skeletal open bite corrected. Moreover, “openbites”, whether anterior or posterior, can also have a dental component associated with them. Let me explain this. A person may have discrepancies in the shape and sixze of the upper and lower jaws. This misalignment many result in a bite where for example the anterior upper and lower incisors do not touch. This person bites down and there is a “hole” of gap between the four upper and four lower incisors. Normally the upper incisors wold overlap the lower incisors much like shingles on a roof. In a skeletal anterior open bite case, these teeth do not overlap at all.
A “dental” (versus skeletal ) component may also be concurrently present. A person with a strong thumb sucking habit could cause the upper incisors to flare out and forwards, creating a gap between the upper and lower incisors. In summary, a person can have poor overlap of the front incisors based on skeletal, dental, or a combination of skeletal and dental reasons.
To more fully address your situation Vic, it would be helpful if you could attach some images of what you are describing. I am having to fill in what I think you are describing. So what is the bottom line here.
My practical suggestion is the following.
I am going to make an assumption here Vic, and that what you don’t like is the prominence of your lower jaw, and specifically the forward orientation of the tip of your lower jaw. If it is your chin that you don’t like, there are some very limited procedures which can reduce the “ chin button” appearance which some people find objectionable. This is known as a genioplasty or chin augmentation procedure. This can be used to enhance a weak chin or to reduce an over prominent one. It is a relatively straight forward procedure, and I would recommend that you consult an oral surgeon and an orthodontist in order to plan this possible next step. A plastic surgeon can also provide this service, but be sure that you bring the Orthodontist into the discussion so that the bite vs. profile relationship is nor ignored. You may wish to also discuss the TADS option with your orthodontist, but I would be truly amazed if he/she would recommend that as a significant remedy for what I believe you are describing as a “chin” related aesthetic discrepancy.
I hope you have not minded this somewhat complex explanation, but your question is very sophisticated. I am limited in developing a response as I do not have the benefit of any pre and post treatment diagnostic records and I obviously have not had the opportunity to see you as a patient. If you have further questions after consulting with your doctors in Montreal, please feel free to submit a follow up question. Any records you can submit would be helpful as well.
Bonne chance Vic
Paul Supan, DDS, MA, MPH
Board Certified Orthodontist
Specialist in Orthodontics
Specialist in Dental Public Health
Please allow a week for a reply. I am in full time Private Practice, lecture on occasion, and involved in many volunteer activities. I am therefore not always able to respond to questions straight away. Your understanding is appreciated.