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ORTHODONTIC TREATMENT TOPICS:
HOW DO BRACES WORK, MOVE TEETH, AND CHANGE THE FACE
TYPICAL ORTHODONTIC TREATMENT FOR A GROWING CHILD WITH CROWDED TEETH
TWO PHASE ORTHODONTIC TREATMENT FOR YOUNGER CHILDREN
INVISALINE ORTHODONTIC TREATMENT FOR ADULTS AND OLDER TEENS
HOW DO BRACES WORK, MOVE TEETH, AND CHANGE THE FACE?
The braces are just a tool which is attached to the teeth. Each bracket, the device bonded or glued to the tooth, is really like a high-tech handle which is precisely placed by the doctor. Each bracket is part of a chain of precisely angulated, machined groves into which a wire is introduced to guide the teeth into the desired position.
When the braces are first placed, if the teeth are all jumbled up and crooked, then the brackets will also appear out of place. However, each bracket is precisely placed by the doctor, with an orientation to coordinate with every other bracket.
The idea is to have all the brackets end up on the same level and in a straight line, which will result in the teeth being aligned. This alignment is accomplished by progressively changing the size and strength of the wires which pass through the brackets. When the braces are first placed, a very soft, low pressure wire is placed, so the patient is allowed to gradually accommodate to the pressure. In general, it takes about five or six weeks to see the results of each wire or system change. This is why we space out our appointments at these intervals.
During the first few months of treatment, the object is to gain alignment of all teeth as they relate to one another. We don't start working on the bite or jaw position until this alignment is complete. We will change the wires as treatment progresses until the bracket alignment is adequate to comfortably allow the placement of a large, hard and ideally shaped stainless steel wire. If a bracket is broken off or a new tooth is added to the system, we have to go back to the soft highly flexible wires again to re-align. This requires us to progressively work back up to the large and heavy stainless steel wires used to stabilize the teeth during the working phase of treatment when elastics and other appliances are attached to the teeth.
The teeth move through the bone in response to light continuous pressure. It takes time and it cannot be hurried. Everyone has a different biological response time, and sometimes that response to pressure has to be found experimentally.
No two people respond exactly alike. This is why one person may finish their treatment months earlier than another with a similar problem. This is also where cooperation with the use of elastics and brushing come into play. The continuous pressure to the bone is applied through the use of elastics, and if the cooperation is not as instructed, then the teeth or jaws do not move.
Those individuals who make the most progress with their treatment are the patients who closely follow the instructions regarding elastic wear when elastics are prescribed.
The oral hygiene of a person can greatly effect the movement of the teeth, because teeth do not move well in the presence of infection. This is why we are constantly monitoring the brushing and cleaning habits of our patients. Other factors which effect treatment are habits such as tongue thrusting, and lip or finger sucking. These habits introduce forces which are far greater than the braces can overcome, and will invariably defeat any effort made by the orthodontist.
TYPICAL TREATMENT PLAN FOR A CROWDED, NON-EXTRACTION CASE IN A GROWING CHILD:
The ideal treatment assumes enough room is available or can be made to avoid extraction of permanent teeth.
Typical non-extraction orthodontic treatment for this problem will involve placing highly detailed braces on all the upper and lower teeth. Frequently, only the upper braces are placed to start treatment. After the uppers are aligned, then the lower braces are added. The braces are designed with a slot in the front of the metal attachment which precisely accepts a wire. The slot is rectangular in shape, with the front of the rectangle open to accept the wire. The wire diameter can vary from rectangular to round in various diameters and stiffness. Recent wire technology has given the orthodontist the ability to move teeth in half the time that it used to take to gain the initial alignment of the teeth.
The first months of treatment are dedicated to unraveling the front teeth and gaining symmetrical alignment of the right and left sides of the dental arches by using small diameter, flexible wires. These first wires are made of a nickel-titanium alloy which is very flexible, exerts low force, but is long acting. These wires remain in the braces from one to four months before they complete their job. The time depends on how crowded or out of alignment the teeth are initially. Of primary importance is elimination of any and all rotations. Rotations have the highest relapse potential.
When there are teeth which are unerupted, it will take time to allow these teeth to erupt and space must be made and maintained to allow normal eruption. The key to gaining alignment in the front of the mouth is to use space which may be naturally available. The permanent bicuspid is smaller than the baby molar which it replaces. This extra space is manipulated with the braces, but sometimes the replacement bicuspid is too large and there is not enough extra space. In this case, the treatment plan will be altered to consider extraction, but 99% of the time...no teeth will be removed.
Next comes leveling of the vertical aspects of the teeth to conform to larger nickel-titanium wires which fully engage the diameter of the slot of the braces. The first objectives are to gain a normal curvature, angulate and parallel the roots of the teeth, and to achieve coordination of the shape of the upper arch to the lower arch.
After initial alignment, large stainless steel wires are placed which again fully engage the inside diameter of the braces. This is the stabilization phase of the braces.
The use of elastics may be necessary to correct positions of various teeth or the midlines. Time and force are dependent on the problem and cooperation.
After the teeth are deemed to be stable in their alignment, the braces are removed and a fixed retainer is placed on the back of the lower teeth to hold them in place. The upper teeth are held with a removable retainer. Retainers are worn for two or more years depending on the original problem. The lower retainer should be worn as long as possible as the highest rate of relapse will be with the lower front teeth.
With younger children (ages 7-11), who have facial deformities, chewing difficulties, or psychological problems due to peer group teasing, sometimes the best way to treat the child is with two phases of orthodontic treatment. An early interceptive phase may be necessary to correct the more obvious problems, and then treat the routine problems later in a second phase. Take a look at How Children Grow for more extensive information on treatment planning.
The first phase of treatment is to make the younger child appear more normal for their age group, and is accomplished with short term partial braces, or a removable appliance. A second phase occurs later in the teens using full braces to detail the final position of the teeth.
Phase one types of Treatments: With limited objectives which can be treated in less than a year:
- Palatal expansion can be performed after the upper first molars erupt using an appliance to widen the upper jaw.
- Alignment of severely crowded or severely protrusive teeth. Partial braces in only one arch is usual, and time in the braces is limited. Generally, the objective is to correct some major malformation or abnormal eruption pattern, and then hold that position until more growth occurs.
- Habit correction involving fingers, thumbs or a dreaded tongue thruster.
Phase Two Treatment: Full treatment objectives treated in less than two years:
- Full tooth alignment and final positioning of the jaws. This phase of treatment is the typical comprehensive teen orthodontic treatment initiated at age 11 to 12.
The advantages of phase one or early interceptive correction are: improved facial appearance, improved chewing during critical formative years, and drastic improvement cosmetically. Results with the first phase usually occurs within 6 to 12 months with normal growth.
The ultimate goal is a 'normal' face and a pretty smile which is pleasing and functionally correct. The earlier treatment is started, the sooner we can establish a normal environment for natural growth and development.
Psychologically, two phase treatment addresses the severe problem early, and avoids the social implications associated with not being 'normal'.
To review: instead of one comprehensive course of treatment as a teenager, the idea of two phase treatment is to allow the young, growing, child to have deforming problems solved early. We don't want them to suffer with these problems through the years when we usually are waiting on teeth to erupt and the face to grow. The typical age when full treatment is started is age eleven to thirteen. With phase one treatment, we are treating problems in the seven to nine year old range, so the child and the parents do not have to deal with a facial deformity until the usual age of usual orthodontic treatment.