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Pre and post orthodontic treatment changes in the sagittal and vertical skeletal dimension following all four first premolar extractions.

Objectives: To determine mean change in sagittal and vertical skeletal dimension in patients undergoing orthodontic treatment with all four first premolar extractions. Study Design: Quasi-experimental study design. Setting: Department of Orthodontics, Dr. Ishrat-Ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences, Karachi. Period: Six months from 18th August 2015 to 18th February 2016. Material & Methods:  50 cases treated with all first premolar extractions were included in this study. The analysis was done on pretreatment cephalogram taken at time of enrolment and post treatment lateral cephalogram taken after 12 months of orthodontic treatment and then their measurements were compared to find out changes in the sagittal and vertical dimension. Results: Pre and post mean SNA, SNB, ANB and Pog-Nperp was not significant  while mean A-Nperp was significantly changed after 12 month treatment (p=0.002). Regarding angular measurement, pre and post mean SNMP, FHMP, MMA, Go-OP, SN-OP, Y axis was not significant while mean SN-PP, UI_SN, IMPA was significantly reduced after 12 month treatment. Similarly vertical measurement, pre and post mean LAFH, PFH was not significant while mean UAFH and, TAFH was significantly reduced after 12 months of treatment. Conclusion: Sagittal and vertical skeletal dimension showed no significant change in patients undergoing orthodontic treatment with all four first premolar extractions. Some degree of extrusion was noted in all orthodontic patients who have undergone all four first premolar extractions.