Glabellar vertical line as a reference goal for anteroposterior maxillary position

Abstract

Objective: The aim of this study was to evaluate the use of glabellar vertical line (GVL) as the anteroposterior maxillary position goal. Methods: A cross-sectional study was conducted assessing 129 participants (20.21 ± 1.99 years): 67 women (20.16 ± 1.99 years), and 62 males (20.26 ± 2.06 years). The facial profile photographs were taken with a posed smile in natural head position. The linear distance from the most facial convexity of the upper central incisor (FA) to the goal anterior-limit line (GALL) and also from FA to GVL were measured and compared. Wilcoxon signed-ranks test was applied. To determine the correlation between the distances, Spearman’s correlation coefficient was used. Simple and multiple linear regression were also performed. Results: The GALL-GVL separation was 0.54 ± 1.14 mm (95%CI: 0.34-0.74). A strong correlation between FA-GALL and FA-GVL distances (Spearman’s rho=0.983 [95%CI: 0.976-0.988], p < 0.01) was identified. The FA-GVL distance explains almost all the total variation of FA-GALL (R2=95.84%, p < 0.01). The FA-GALL distance can be predicted by using the formula: FA-GALL=0.5+0.9*(FA-GVL). Conclusion: These findings suggest that GVL could be used as an easier-to-use treatment goal to determine the maxillary anteroposterior position, compared to GALL, to improve facial harmony profile goals in cases where the maxillary incisors are properly positioned anteroposteriorly.