The Contemporary Coben Analysis

Abstract

As orthodontics integrates more digital imagery it has become necessary to reconfigure and adapt the Coben analysis. In its original paper-based form, it is exceedingly time consuming. The objective of this project was to: 1.) Create a novel method for analyzing radiographic cephalometric images in a digital manner using the Coben analysis. 2.) Compare the original norms and standard deviations to the measurements taken on today's patients. 3.) Address any changes in the norms due to secular trends. In the present study 279 digital cephalometric radiographs were separated into 3 age groups by sex. The breakdown is as follows: 53 males age 7-10 with a median age of 8.17 years, 43 females age 7-10 with a median age of 8.67 years, 45 males age 11-14 with a median age of 11.58 years, 50 females age 11-14 with a median age of 11.52 years, 41 males age 15-18 with a median age of 16.08 years and 47 females with a median age of 16.33 years. The cephalometric radiographs were digitally traced using Coben analysis standards to compare to the original Coben analysis norms and assess any differences in secular trends. Based on the results collected, the following conclusions were drawn: 1. As evidenced by the larger standard deviations in the current study compared to the original study, more individual variation exists among the facial skeletal components that form a Class I occlusion than previously thought. 2. We recommend 3.8° should be used for the S-N angle mean in males age 11-14 and 2.9° for females age 11-14 as opposed to the 7° suggested by the original study 3. The hand tracing method previously employed uses graph paper with the coordinate system enlarged 8% to compensate for the 8% enlargement of the radiographic film. This is no longer necessary when tracing a digital cephalometric radiograph. 4. The distance from basion to articulare in this study is consistently within one standard deviation of the original study's measurements for males and females. This distance appears stable for research purposes. 5. The Coben analysis linear and proportional measurements need not be adjusted due to the vast array of variables present in any population which include, but are not limited to, variation in comparative sample populations, genetics, polymorphisms, or endocrine disrupting chemicals.