The effect of primary-canine extraction on the IMPA.

One can expect to lose IMPA or arch circumference after extraction of the primary canines, if the child presents with an initial FMIA of 64 degrees or less. If the initial FMA is 28 degrees or greater, one can probably expect to lose IMPA, if the primary canines are extracted. One may tentatively suggest that in patients with normal FMA's and FMIA's, the extraction of the primary canines will not appreciably affect the IMPA. Space maintainers may not be needed in such cases. Of the twenty-two patients who had primary canines extracted, ten patients lost IMPA and twelve patients had no change or an increase of IMPA. The findings of this study should be replicated with a larger patient sample.