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[A retrospective study of morphologic basis for the extraction decision in Class II, division 1 malocclusion]
Objective:
To compare the dentofacial characteristics of persons with Class II, Division 1 malocclusion treated with either an extraction or a nonextraction approach. Such comparison might help identify which parameters influence the extraction decision.
Methods:
Lateral cephalograms were available on 81 cases of Class II, Division 1 malocclusion, 42 were treated with 4 premolar extractions and 39 were treated with non-extraction. The cephalometric analysis of West China University of Medical Sciences and Model Analysis were used,
Results:
Patients in the extraction group had larger FMA, FMIA and lower anterior facial height. In the group of extraction, the upper anterior teeth tipped more anteriorly, and the tooth size-arch length discrepancy and the depth of Spee curve were greater significantly. But the saggital discrepancy and soft tissue's profiles had no significant difference between two groups.
Conclusion:
The stability of the triangle of Tweed, the tooth size-arch discrepancy and the depth of Spee curve were the keys to decide weather extraction or not.