Patient Movement During Digital Cephalography Using Slit-beam Scan

Objectives: The objective of this study was to quantify the degree of patient movement during the digital lateral cephalography using the slit-beam scan which is popularly used in digital cephalographic machines.

Methods: Fifty three volunteers (32 men, 21 women; average age 20-year-old) were divided into three groups by age and three conditions according to the patient notification; The first condition: volunteers were not given any instruction, The second condition: volunteers were notified to minimize the movement during cephalography. And the third condition: volunteers were asked to clench the teeth lightly. During the cephalography volunteers were set in the slit-beam scan digital cephalographic machine and the degree of head movement was measured in three dimension for 30 seconds using the optical tracker (PolarisⓇ, Northern Digital, Canada). The sum value of movements in three dimensions was used in statistical analysis.

Results: Movement in y-axis (up and down) was 2.58 mm and the largest (p<0.001) and female patients(5.18 mm) moved more than male (4.25 mm) (p<0.05). By age group, patients in the first group (between 9-year-old and 12-year-old) showed the largest movement (13.54 mm) in all experimental conditions (p<0.05). There was no significant difference among experimental conditions. However, patients in the second condition showed the least movement (2.88 mm) when the age group 1 was excluded (p<0.05). With the passage of time, the movement was increased from 3.31 mm to 6.65 mm (p<0.001).

Conclusions: This study confirmed that the patient movement during the digital lateral cephalography using the slit-beam scan was large. Much effort to reduce the patient movement will be required.