Growth and Treatment Changes Distal to the Upper and Lower First Molars: Holding the E-Spaces vs Extractions of Upper First and Lower Second Premolars

Aim: This study was designed to examine the three-dimensional changes in the positions of the upper and lower first molars, following two different contemporary treatment methods. Method: Retrospective records of 82 fixed appliance orthodontic patients were divided into two groups. In one group, 43 patients had been treated with upper first and lower second premolar extractions, with no deliberate attempt to hold the upper or lower molars back other than for individual anchorage requirements. In the other group, 39 patients had been treated by holding the E-spaces, with definite attempts to limit the forward movement of the maxillary first molars with utility arches and headgear. Follow-up written treatment records and radiographs were also examined to determine whether mandibular third molars, if initially present, were ultimately extracted or retained. Results: The results confirmed that treatment methods involving the holding of E-spaces do tend to limit the amount of forward movement of the first molars, whereas treatment involving the extractions of upper first and lower second premolars tends to result in some forward movement of the first molars during planned movements and space closure. Conclusions: Such a difference in molar movement is likely to significantly influence the amount of space available for the eventual favorable eruption of the second and third molars. The results also suggested that, within premolar extraction groups, the amount of growth occurring during and after treatment is likely to play the most significant role in determining the space available for eventual third molar eruption.