The purposes of this study were to evaluate the reproducibility of posteroanterior(PA) cephalograms obtained by two methods, the Head Posture Aligner(HPA) method in natural head posture and the conventional method(operator-guided method), and to compare the vertical rotational differences of the head posture between lateral and PA cephalograms according to the method
The sample ´vas consisted of 30 adults. At first day, a PA cephalogram and a lateral cephalogram were obtained from each subject by two methods to investigate the difference of vertical rotational posture between lateral and PA cephalograms. Two weeks later, another PA cephalogram was obtained using each method to evaluate the reproducibility of head posture. Five height measurements and nine width measurements were used in the paired t-test to compare the reproducibility of the PA cephalometric measurements between two methods. The differences of vertical rotational posture between lateral and PA cephalograms were calculated from a computer program and compared according to the method used, and following results were obtained.
1. Height measurements obtained by operator-guided method showed significant differences according to the time interval and revealed low reproducibility.
2. Height measurements obtained by HPA method did not show significant differences according to the time´. interval and presented high reproducibility.
3-In the comparison of width measurement, two methods´,did`not show distinct differences in reproducibility.
4. The difference of vertical rotational posture between lateral and PA cephalograms showed 0.8°in the HPA method, more less than 2.5-in the operator-guided method.
The results of the present study suggest that the HPA may be helpful in the PA cephalometric radiography in terms of reproducibility.
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