Assessment of the anteroposterior soft-tissue contour of the lower facial third in the ideal young adult.

An evaluation of the normal anteroposterior positions of five soft-tissue points inferior to the nose was undertaken for a selected sample of twenty-five male and twenty-five female young adults exhibiting pleasing (good) facial profiles and normal sagittal and vertical skeletal relationships. The subjects were selected from dental, dental hygiene, and graduate students at Baylor College of Dentistry by three members of the graduate orthodontic faculty and two members of the oral surgery faculty of the dental college. Cephalograms were taken with the subjects in natural head position, thus establishing a true extracranial horizontal reference plane. A true vertical reference plane was constructed perpendicular to the true horizontal, through subnasal. The five soft-tissue points were measured linearly relative to this subnasal vertical plane. Means, standard deviations, and standard errors were calculated for the five points. In addition, the same soft-tissue points were analyzed relative to the Frankfort horizontal and to a nasion vertical perpendicular to the true horizontal and the Frankfort horizontal. The use of the subnasal vertical perpendicular to the true horizontal was shown to have the smallest standard deviation of the four methods.