Reliability of the integrated radiograph-photograph method to obtain natural head position in cephalometric diagnosis

Abstract

Objective: To introduce a simple and reliable method to reorient lateral radiographs to the natural head position (NHP) according to standardized photographs made at NHP. Material and Methods: The study has two parts. In the first part, 45 patients were randomly selected from a patient cohort. Photographs (at NHP) and cephalograms from each patient were taken and assessed in two sessions by two observers. The time between the first and the second session was 5 weeks. The repeatability of profile measurements on cephalograms compared with standardized photographs of the same patient was determined; in the second part, the repeatability of three superimposing protocols (ie, the soft tissue N/subnasale line [V-line], the esthetic line [E-line], and a proposed nose best fit line [N-line]) was compared for the reorientation of the cephalogram according to the photographs made at the NHP. Results: Our results showed that the integration of radiographs and photographs is an objective and reliable method to obtain NHP in lateral cephalograms. The N-line is a reproducible and stable reference line for the reorientation of radiographs to obtain NHP. Conclusion: Reorientation of radiographs according to standardized photographs made at the NHP is a reliable and objective method to standardize the radiographs at the NHP for cephalometric analysis. The N-line is a reproducible and stable reference line for the reorientation. It is preferred over the V-line or even E-line, especially when the radiographs and photographs are taken at different sessions or at different treatment stages