Mankind’s ancestors had large, heavy jaw structures that easily accommodated thirty-two teeth. Over the course of thousands of years, jaw structures have become reduced, but the size and number of teeth have remained the same.
The last permanent teeth that erupt between the ages of 18 and 25 are the third molars or Wisdom Teeth. They are supposed to erupt behind the second (twelve) year molars at the very back of the mouth. For many, the trend toward a smaller jaw structure creates a space problem for the wisdom teeth. When there is not adequate space for teeth to grow into the correct position they remain beneath the surface of the gum tissue, embedded in the jawbone. This condition is called impaction.
An impacted wisdom tooth may never create any problems, but some impactions can become infected or create a cyst. lmpactions can affect the alignment of other teeth. They may cause discomfort or damage adjacent teeth. Unfortunately there is no way of knowing whether the wisdom teeth will cause these problems. If impacted wisdom teeth are detected, we will probably recommend that they be extracted. The least difficult time to remove wisdom teeth is in the late teen years.
Please ask us any questions that you have about wisdom teeth.
Growth of the Face
Growth of the face is of critical importance to the orthodontist. It is a constant subject of study and analysis. Orthodontists try their best to evaluate the individual growing pattern of each young patient in order to plan treatment accordingly. Methods of analysis have been developed from numerous studies on large groups of individuals. Statistics help but the orthodontist never knows exactly what kind of growth to expect in each person.
As teenagers grow the greatest facial changes occur in the lower face. There is a notable increase in the distance from the nose to the chin. The amount of jaw growth a patient might experience during orthodontic care is between none at all and 3/4 of an inch. The amount of tooth movement required to straighten the bite may be less than 1/4 of an inch. So growth of the face can have a tremendous impact on the progress of the treatment. Growth can help or hinder tooth movement. Usually it helps treatment progress Growth can also change course in the middle of the treatment and this is one reason it is difficult to predict how long a patient will wear braces.
Careful analysis and constant monitoring are required. Orthodontists often observe a patient for a few years before work actually begins. A jaw structure x-ray (headfilm) is used to evaluate growth jaw size and relationship and asymmetries. Comparison is made between the measurements made on the headfilm and standard measurements from accepted studies. Dramatic improvement can be made in jaw structure by using growth modifying appliances.
A careful consideration of the patient’s growth patterns will help achieve the desired treatment goals.
Options for Severely Crowded Teeth
The goal of all orthodontic treatment is to produce a healthy well-functioning stable dentition. Whenever teeth are moved by orthodontic pressures, tissue memory tends to move them back a bit toward their original position. When possible, we want to design the treatment so that the teeth grow in as close as possible to the correct position. This is the premise of orthodontic interceptive treatment.
The most common orthodontic problem is poor alignment due to crowding of the teeth. The genes for tooth size and jaw size are not always in harmony Sometimes the tooth size is simply too large for the jaw. Many studies have shown dentists that removal of certain permanent teeth is the best treatment solution for extreme crowding. If the extractions are done early in the dental development we can head off the occurrence of severely displaced teeth. If the teeth grow into a reasonably good position, the gum and bone form around the teeth normally.
Serial extraction is sequential removal of certain baby teeth and then four permanent teeth over a period of years. We recommended serial extraction only in severely crowded cases where there is no hope of providing enough room through other treatment methods. It is best to begin before the eight incisor teeth are fully grown in. First some primary teeth are removed (usually primary canines). This allows us to borrow space for the permanent incisor teeth that are emerging in a portion of the jaw that is not large enough. We can have several years to borrow this space, as the permanent canines do not grow in until age 12 or so. At that age we must evaluate the need for removing some permanent teeth, as we want to encourage the permanent canines to grow into a good position. Most commonly we will recommend removal of the four first bicuspids (everyone has a double set of bicuspids), but we must analyze each case individually to determine the best choice of extraction.
You may have questions regarding the safety of the radiation doses you or your child receive. Radiation safety has fortunately evolved a great deal in the past two decades. Today radiation exposure from orthodontic and dental x-rays is quite low. There are a number of different types of and sources of such radiation, which can be measured in units of millirems (mrem).
Is X-Ray Radiation Harmful? What Parts of the Body are Irradiated
Our primary concern is the effect the radiation from the x-rays might have on our patients. We worry most about the reproductive organs being affected. The leaded apron we use on every patient is designed to prevent radiation dose to the reproductive organs of the patient. However, even without the apron, the techniques and equipment we use do not allow radiation to reach these organs. Whether or not it is technically needed, we, and most dentists, use the lead apron to be on the safe side.
The thyroid gland (in the neck) is also known to be sensitive to radiation. Although the use of a thyroid collar shield does lower the x-ray dose to the thyroid gland, it also blocks out areas of the neck on an x-ray. We do not use such shields, because we must see the structures of the face adjacent to the neck for diagnostic purposes. The benefit of such a dose reduction has is very small compared to the risks of not diagnosing the structures of the neck. Consider that for a teenage male patient, the normal probability of getting thyroid cancer is 0.0022. In other words about 1 male of every 500 will get thyroid cancer sometime during his life. Exposure to a lateral cephalometric headfilm (with no thyroid shielding) increases the probability by only 0.00000009 (about one in 10 million), or about 0.004%. A full mouth x-ray series (20 films) increases the risk of thyroid cancer by 1 to 2 per million.
We hope this information reassures you about the safety of our x-ray procedures. We are concerned about radiation safety for each patient and our staff and consequently we use the latest methods and technology. If you have any further concerns, please do not hesitate to ask one of the doctors.