Extraction vs. Non-Extraction - Part 6: Removal of permanent teeth and the length of orthodontic treatment

Whenever there is a decision to make regarding the removal of permanent teeth,the length of treatment time must be considered in this decision-making process. Removal of permanent teeth may be necessary to alleviate crowding, but it is often used as a treatment technique to address inadequacy of growth in one or both of the jaws. Either way, the amount of crowding present when teeth are extracted, or the lack of crowding present will have the greatest impact on the length of treatment.

When there is very little crowding present at the onset of treatment and it is recommended that permit teeth be removed, there will often be large spaces that need to be closed. Space closure in general takes approximately one to one and a half months for each millimeter of space to close. And when removing permanent teeth, the most often removed permanent teeth are first premolars. These teeth are generally 7 to 8 mm wide; therefore space closure will generally take on average between 6 to 12 months in the absence of significant crowding resulting in protracted treatment time. On the other hand, if significant crowding (10-14 mm) is present prior to treatment, then there will be very little space to close, resulting in a very short treatment time.

When taking into consideration the non-extraction approach, the more significant the crowding, the longer the treatment will take to complete. And just the opposite, the less significant the crowding, the shorter the treatment will take to complete without removing teeth. Often deciding to remove teeth or not, the extreme cases are easy to determine when to extract or not extract. It is usually the cases that lies somewhere in the middle, those that present with 6 to 10 mm of crowding that are often not so cut and dry and must involve consideration of the factors discussed in the previous blogs.

 In the final blog on this matter we will consider cost in this decision and discuss the pros and cons of removing permanent teeth related to treatment cost.