The effect of first premolar extraction on vertical dimension

The purpose of this study was to evaluate the vertical changes occurring in Class I patients treated orthodontically with first premolar extraction an d to compare these changes with those occurring in Class I patients treated orthodontically without extractions. Records of 40 Class I nonextraction c ases (24 girls, 16 boys) and 40 Class I maxillary and mandibular first prem olar extraction cases (23 girls, 17 boys) were obtained. The pretreatment a nd posttreatment cephalograms were digitized, and 6 linear and 8 angular ce phalometric measurements were selected to evaluate vertical changes. Evalua tion of the treatment results of the extraction and nonextraction cases sho wed that the vertical changes occurring after the extraction of maxillary a nd mandibular first premolars were not different than those occurring in th e nonextraction cases.