Freedom Through Expansion
Pictured: Dr. Pfister looks at a human skull, and he’s got “expansion” on the mind.
The nineties changed a lot of how we approach the correction of dental malocclusions (imperfect positioning of the teeth when the jaws are closed), both cosmetically and functionally…
If you had braces 25 plus years ago, it’s a darn good bet that you had four teeth extracted before the braces were placed. I had four teeth removed. My wife, sister, brother all had the same approach to orthodontic correction. Basically, it was called the four on the floor technique; and what you were doing was reducing the number of teeth to fit the size of the jaw.
In the early nineties, I was removing bicuspids in 80% of our cases. The other 20% had too much space and we corrected the bite by closing all of these natural spaces.
But by the turn of the millennium, we were only extracting teeth in 30-40% of the cases. So what changed?
The change occurred at the skeletal level, in expansion of the upper and lower jaws. This expansion was possible as we learned to apply the proper pressure at the suture line of both jaws, thereby causing them to open up and move apart. This, in turn, created a larger footprint of the upper and lower jaw. Thus, rather than extracting teeth to fit the bone, the new concept was to expand the bone to fit the teeth. But to do this, orthodontic treatment had to be started much earlier than ever before. The orthodontist needed to expand the suture, while it is pliable, and the earlier the better for correction of the eruption trajectory of the permanent teeth. But there are limitations… and they are based again on the sutures of the jaws.
So what is this skeletal suture thing? Glad you asked.
The bones of the human skull have large, flexible, fibrous joints (or sutures). The sutures first allow the head to compress and pass through the birth canal and then later on to postnatally expand for brain growth. According to P. M. Som and T. P. Naidich in the American Journal of Neuroradiology, the human palate forms between the sixth and 12th week of life as the embryonic right and left paired skull bones come together. Disruption of this skeletal sutural formation during this time leads to cleft lip and palate formation. The upper and lower jaw’s midline sutures ossify or solidify earlier in girls than boys, but it’s felt this solidification occurs in late teens for both. Proper expansion with minimal discomfort to the patient needs to be initiated before ossification takes place.
As scientists and the dental community better understood the sutures, manipulating and stimulating their growth (to increase the width of both jaws) was a natural step for orthodontics.
My last two years in dental school, in the early eighties, I had the privilege of doing research with Dr. Don Enlow, Dean of Case Western Reserve, and Dr. James McNamara, Chairman of U. of M. Dental School, both of whom wrote various books and lectured extensively on early treatment and expansion of the suture systems. Their work gave credibility and acceptance around the world to the utilization of removable expanders for sutural stimulation (which were first invented by Andrew Haas in Cuyahoga Falls, Ohio!). Eventually, Andrew and the orthodontic community moved to cemented-in expanders for better direction of the energy and control of the sutures as they are moved apart.
“So this all sounds biologically exciting, but how does it affect my child’s overbite?” you ask.
Those of us who had teeth extracted didn’t go to the orthodontist until eighth or ninth grade. And once the teeth were extracted, we went directly into full braces. Braces, as you know, are a dental moving appliance, whereas the expanders are skeletally moving appliances. So the creation of a pre-brace skeletal phase is designed for those usually under ten years of age. The goal of this phase is to increase the width of the upper jaw primarily and secondarily the lower (if crowding of the lower teeth dictates).
The increasing of the upper jaw’s width, right and left, provides space for the anterior teeth and provides the room for the proper eruption of the upper canines. This is very critical, because if the upper canines do not have the proper space, they tend to erupt toward and become impacted on the palate behind the other anterior teeth. Once impacted, it takes an oral surgeon to expose them and surgically place a bracket with a mini brass chain.
The orthodontist, then, after placing the upper braces, attaches an elastic thread to the chain and - with constant force over the next six to eight months - they are lifted off the palate and into proper position. This is not only financially costly for the parents, but emotionally costly for the patient. Most of this could have been avoided with proper arch expansion at an earlier time in the child’s life. And all of this effort is necessary due to the fact that upper canines are the key anterior support teeth, as they stabilize and guide our lower jaw in closure, balance our bite, and guide our chewing for the remainder of our lives!
Expansion of the upper jaw has several other very significant collateral benefits for the growing child that may surprise you.
The main reason for getting our second 3-D cone beam x-ray machine four years ago was for airway evaluation of our patients. I had spent two years with the I-Cad company in a learning program for attention deficit, sleep apnea, and ADD / ADH behaviors associated with constricted airway. Along with eliminating obstructions (tonsil and adenoid removal), orthodontic expansion of the upper jaw allowed the lower jaw to move forward and reach its genetic potential, thereby opening the patient’s airway. Research has shown if the upper jaw stays narrow during the window of opportunity to grow (puberty), then the lower jaw is held in a retruded position, never reaching its genetic potential. Consequently, the patient’s airway remains constricted.
Once sleep apnea is diagnosed, most patients are the other side of 30 and only jaw surgery will open their airway. In fact, the number one way to get rid of the c-pap machine as an adult, is for lower jaw advancement surgery. The proper growth of the lower jaw also aids in the eruption of this generation’s 12-year molars, which of late have shown increases in impaction, like the classic wisdom teeth (due to shortness of the lower jaw).
And finally, short lower jaws with the subsequent overbites can even affect how the jaw functions at the TMJ. The temporomandibular joint, TMJ, is the functional attachment of the lower jaw to the upper skull. It is a ligamentous attachment, allowing the lower jaw flexibility to close in an arch and to properly function with the upper jaw. However, if the lower jaw never reaches its genetic potential and remains short, the arch of its closure does not fit properly with the upper. The patient then has to stretch their lower jaw every time they want to fit properly with the upper. Expansion of the upper jaw at an early age with the subsequent freedom for the lower jaw to grow has significantly reduced TMJ occurrences since the 90s, especially in woman.
There is nothing that today’s orthodontist can do for his or her patients with more long-term return on investment for the child’s health than to expand the upper arch at an early age, 9-11 years of age.
It is, I feel, a perfect example of Ben Franklin’s saying that “An ounce of prevention is worth a pound of cure!”
Until next time, stay classy Medina County,
- Dr. Pfister