Extraction of a lower incisor may be indicated to relief crowding. It is the case if the crowding in the lower arch is more than 6mm and if bilateral premolar teeth extraction is not desirable. However extraction of a lower incisor is not indicated for every case as it requires proper case selection.
Extracting a lower incisor will introduce a size difference between the upper and lower teeth, this may result in:
- an increased overjet (increased distance between the upper and lower front teeth) as there are less teeth in the lower arch
- non coincidental midlines, the upper dental midline (the line between the 2 front teeth) will now lie in the middle of the 3 remaining lower incisor
- change in the bite at the back teeth due to the size discrepancy between the back teeth
However there are certain cases that will benefit from a lower incisor extraction especially if
- The upper teeth are small (e.g pegged shaped lateral incisors), hence the distance between the upper and lower teeth will not be so great if 1 lower incisor was extracted.
- There is a severely compromised lower incisor due to poor gum health, bone support or a history of trauma
- The bite at the back teeth is good and the upper arch has minimal crowding whilst there is moderate crowding of 6mm or more in the lower front teeth region
Proper case selection is an important consideration in a lower incisor extraction treatment plan. One of the advantages of using Invisalign is that a treatment outcome simulation is planned prior to treatment.
A tooth size analysis is also done and this gives your dentist/orthodontist a firm idea of how much interproximal reduction may be necessary to reduce the resultant increased overjet. You will also be able to visualise what is the planned outcome and discuss with your doctor any of your concerns.
Hope this helps and all the very best,
Dr Priscilla Lu
Orthodontist
