Effects of Different Head Positioning Methods on Facial Soft Tissue Analysis Using Stereophotogrammetry

Publication date: Available online 19 February 2019

Source: Journal of Oral and Maxillofacial Surgery

Author(s): Nisa Gul Amuk, Kübra Gulnur Topsakal, Hasibe Baser Keklikci

Objective

The purpose of this study was to compare sagittal tilt of the head in different head positioning techniques by an inclinometer and facial stereophotogrammetry measurements among different head positioning records.

Methods

The study was carried out in forty-five subjects (26 female, 19 male). The head positioning of the subjects was obtained with dynamic walking, Frankfort horizontal plane (FHP'), self-balance+mirror and subjective photographic positioning methods. All pitch values were recorded by an inclinometer and stereophotogrammetric images were obtained. The facial analysis included distances of the points G', Pn, A', Ls, Li, B', Pog' to the true vertical line (TVL) and face height, lip length measurements.

Results

The head positions of the subjects were observed to be more forward in the FHP' head positioning technique in comparison to the other methods, while more backward head position was recorded with subjective head positioning significantly (p<.001). There were no significant differences between the pitch values of self-balance+mirror and dynamic walking methods. G'-TVL (p<.000), Pn-TVL (p<.029), A'-TVL (p<.039), Ls-TVL (p<.001), Li-TVL (p<.037), B'-TVL (p<.003), Pog'-TVL (p<.000) on profile and face height, lower face height and lower lip length values on front-view (p<.001) differed significantly due to the head positioning methods.

Conclusion

Dynamic walking and self-balance+mirror head positioning methods offered similar and advisable natural head position results while FHP' head positioning was questionable in accurate determination of natural head position. Facial soft tissue measurements like face height, lower face height, lower lip length and projection of structures like glabella, pronasale, lips and chin varied based on the head positioning methods.

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