Mueller B H, L'Homme P R, Schoenbrodt F A, Ayer W A
ASDC J Dent Child. 1978 Nov-Dec;45(6):461-4.
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.
如果儿童最初的功能性下颌前牙反合角（FMIA）为64度或更小，拔除乳尖牙后可能会出现下颌平面角（IMPA）减小或牙弓周长减小。如果最初的面角（FMA）为28度或更大，拔除乳尖牙后可能会出现IMPA减小。可以初步认为，在FMA和FMIA正常的患者中，拔除乳尖牙不会明显影响IMPA。在这种情况下可能不需要间隙保持器。在拔除乳尖牙的22例患者中，10例患者IMPA减小，12例患者IMPA无变化或增加。本研究的结果应用更大的患者样本进行重复验证。
