(18), statistically significant gender differences were found for the thickness of the labrale superius
, labrale inferius, Pog and menton measurements.
The thickness at labrale superius
and stomion points among each skeletal type was signifi- cantly the greatest in Class III for both males and females.
Caption: FIGURE 1: Points and plains used in cephalometric analysis: Gl; (soft-tissue glabella), Prn (pronasale), Cm (columella), Sn (subnasale), Ls (labrale superius
), Li (labrale inferius), Pg; (soft-tissue pogonion), Pg (osseous pogonion), Gn (gnathion), Me (menton), Go (gonion), Ba (basion), Co (condylion), Po (porion), Pt (pterygoid point), S (sella), PNS (posterior nasal spine), ANS (anterior nasal spine), N (nasion), Or (orbitale), Ap + 1 (apicale superius), Ap - 1 (apicale inferius), In + 1 (incisale superius), In - 1 (incisale inferius), NSL (nasion-sella line), FA (facial axis), NL (nasal line), MP (mandibular plane), FH (Frankfort horizontal), E (Ricketts' Esthetic line), and S (Steiner's line).
The proposed method of locating the posterior columella point onto which a tangent was drawn to the lower border of the nose as well as the line from this point to labrale superius
proved to be a reliable technique for constructing the nasolabial angle.
Soft tissue points were selected bearing in mind that they are directly located, i.e., they are constructed points, so it was not necessary to draw anatomical structures, which are usually operator-dependent, thus allowing bias control during the study; these points were: labrale superius (Ls), labrale inferius (Li), subnasale (Sn), glabella (G'), columella (Cm), menton (Me), pogonion (Pg'), stomion superius (Stms), stomion inferius (Stmi), and lower vermilion (Vmi).
Regarding the Y axis, the highest averages were observed in labrale superius (0,687 mm) and menton (0.672 mm).
Interobserver error averages greater than 1 mm were observed for conventional radiography in chin (1.214 mm) and pogonion (1.043 mm), and for digital radiography the averages greater than 1 mm were chin (1.206 mm), pogonion (1.131 mm), labrale superius (1.041 mm), labrale inferius (1.027 mm), and lower vermillion (1.015 mm), with no statistically significant differences between the methods.
Another finding of the present study indicates that in digital radiography labrale superius, labrale inferius, and lower vermilion presented interobserver error values greater than 1 mm, but with no significant differences compared to conventional imaging, suggesting that the lower vermilion was more difficult to locate because two-dimensional radiographic imaging does not clearly show where the lower lip ends.