• Paiboon Techalertpaisarn
• Chaiwat Varaubol
• Sampan Tingtanathikul

Objective This objective of this study was to determine reproducibility of head orientation in sitting and standing body postures with and without mirror for limiting eyesight level.

Materials and methods Subjects consisted of 38 dental students (13 males, 25 female) with average age of 21 years 1 month. Lateral photographs were taken by a digital camera with same settings in 4 positions. There were 1) sitting posture and looking forward 2) sitting posture and looking forward into the mirror at eyesight level 3) standing posture and looking forward 4) standing posture and looking forward into the mirror at eyesight level. Photographs were taken at two different occasions with at least 1 month interval. Angle between Glabella-Subnasale Line (GSL) and True Vertical Line (TVL) was measured from every photograph using a computer program (Photoshop 7.0). This angle was used to represent the subjects’ head orientation.

Results The result showed that there was no statistically significant difference between 1st and 2nd GSL in all four positions. The differences of the GSL-TVL angle in sitting, sitting with mirror, standing and standing with mirror between 1^st and 2^nd occasion were 1.16, 0.50, 0.14 and 0.13 degrees, respectively. The method errors of the GSL-TVL angle in sitting, sitting with mirror, standing and standing with mirror were 2.99, 2.95, 2.78 and 2.46 degrees, respectively.

Conclusion The study can be concluded that head orientation in standing posture had tendency of more reproducible than that in the sitting posture. Head orientation in sitting posture was more upward than that in standing posture. Furthermore, the use of mirror to limit eyesight in sitting position may increase the reproducibility of head orientation.

(CU Dent J 2003;26:193-9)