• The korean journal of orthodontics
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• v.40 no.2
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• pp.77-86
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• 2010

Objective: The purposes of this study were to evaluate the reproducibility and reliability of head posture obtained by registering outer canthus as a soft tissue landmark with the Outer Canthus Indicator (OCI). Methods: Twenty-one adults with normal facial morphology were enrolled in this study (mean age $27.5\;{\pm}\;1.72$ years). To register initial head posture, height of the outer canthus from the ear rod plane was measured using OCI. Head posture was reproduced by moving the head upwards and downwards until the outer canthus was in a straight line with the indicator set at a registered height. After the head posture is reproduced by two operators after two days, lateral photographs were taken. Computerized photometric analyses of the photographs were performed. Results: The head rotations around the transverse axis were $0.69\;{\pm}\;0.43^{\circ}$, $0.98\;{\pm}\;0.65^{\circ}$ from each of the two operators. Standard errors were $0.09^{\circ}$ and $0.14^{\circ}$ each, which were similar to results from past research findings. There were no significant differences between the data from the two operators (p > 0.05). There were no correlations between the head rotation around the horizontal and vertical axes (p > 0.05). Conclusions: The present study suggests that OCI-registered head posture may minimize errors from vertical head rotation in cephalometry and photometry.