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

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.