Recording natural head position using an accelerometer and reconstruction from computed tomographic images

Recording Natural Head Position Using Cone Beam Computerized Tomography

The purpose of this study was to develop a technique to record the natural head position (NHP) of a subject using the scout images of cone beam computerized tomography (CBCT) scans. The first step was to align a hanging mirror with the vertical (XY) plane of the CBCT field-of-view (FOV) volume. Then, two scout CBCT images, at frontal and at sagittal planes, were taken when the subject exhibited a NHP. A normal CBCT scan on the subject was then taken separately. These scout images were used to correct the orientation of the normal CBCT scan. A phantom head was used for validation and performance analysis of the proposed method. It was found that the orientation detection error was within 0.88°. This enables easy and economic NHP recording for CBCT without additional hardware.

Cephalometric Evaluation of Natural Head Position in Lingayat Population of Karnataka

Aims and Objectives:

To ascertain norms in cephalometry for 11- to 13-year-old Lingayat children in natural head position (NHP).

Materials and Methods:

Lateral cephalograms of children were obtained by using fluid level device. We determined the variance in Frankfort horizontal plane (FHP) inclination to extracranial horizontal in NHP. The G^*Power, version 20 for Windows was used for analysis.

Results:

Reduced facial convexity was observed when the analysis was carried out in relation to true horizontal with significant difference of “t” value of 3.05 and percentage difference of 1.1 (P < 0.01) and for girls “t” value of 9.69 and percentage difference of 2.5 (P < 0.001). The highest correlation coefficient for Lingayat boys (r = 0.77) was seen between palatal plane and occlusal plane. We found least correlation coefficient among FHP and Sella–nasion plane (SNP). The coefficient was r = 0.62 and correlation coefficient of r = 0.70 was between FHP and determination coefficient r² = 0.38 or 38%. For girls, highest correlation coefficient of r = 0.70 was seen among FHP and palatal plane.

Conclusion:

Conventional study of craniofacial forms of Lingayat children showed the average skeletal pattern as Class II with retrognathic mandible in comparison to Caucasians. However, when seen in NHP by new method of analysis based on the true horizontal, the skeletal model was Class III in comparison to Caucasians.