Re-Examining the Norm Concept in Cephalometrics: Associations Between Subjective Assessments and Deviations from Cephalometric Norms

摘要

The purpose of this study was to investigate the degree of agreement between deviations from cephalometric norms and clinicians' subjective assessments of treatment difficulty and success. Six orthodontists subjectively assessed and ranked complete pre- and post-treatment records of 36 orthodontic patients for difficulty of treatment and favorability of treatment outcome. Twenty-five hard tissue and 20 soft tissue cephalometric landmarks were located and digitized by two orthodontic residents for all pre- and post- treatment headfilms. Each patient's pre- and post- treatment deviations from 7 commonly used cephalometric hard and soft tissue norm sets were determined. The subjective assessments were compared to the deviations from the published and sample's norms. There were no significant correlations between subjective assessments of difficulty or favorability of treatment and degree of deviations from hard tissue cephalometric norms. Significant negative correlations were found between subjective assessments of favorability of treatment and degree of deviations from specific soft tissue cephalometric norms (E-line and H-Line). This data suggests that clinicians' decisions regarding treatment difficulty or treatment success rely more heavily on factors other than coincidence with hard tissue cephalometric norms.