Association of Upper Lip Morphology Characteristics with Sagittal and Vertical Skeletal Patterns: A Cross Sectional Study.

Xinyu Yan,Yiyin Chen,Xiaoqi Zhang,Wenli Lai,Hu Long

doi:10.3390/diagnostics11091713

Abstract

Background: Upper lip morphology is essential in diagnosis and treatment of orthodontics and orthognathic surgery. This study is aimed to evaluate the association between upper lip characteristics (ULCs) and skeletal patterns (SPs). Methods: 2079 patients were involved and grouped by sagittal and vertical. Class I, II, and III were identified by ANB angle, while normodivergent, hyperdivergent, and hypodivergent were identified by Facial Height Index and Sum of Angles. ULCs were evaluated by superior sulcus depth, nasolabial angle, upper lip length, basic upper lip thickness, and upper lip thickness. Confounders including demography, malocclusion, upper incisors, and upper lips were adjusted by multivariate linear regression to identify the association between ULCs and SPs. Group differences were evaluated with analysis of variance and Chi-square test. Results: The mean value of ULCs and prevalence of SPs were explored in the Western China population. ULCs were significantly different in various sagittal, vertical, and combined SPs. Superior sulcus depth was negatively related to Class II, and positively related to Class III and the hypodivergent pattern after adjusted by confounders. Conclusions: ULCs significantly varied among different SPs, while only superior sulcus depth was independently associated with SPs, indicating superior sulcus depth is the only ULC that might be significantly corrected by intervention of skeletal growth.

Highlights

Profile esthetics is generally becoming one of the major objectives of patients seeking orthodontic or orthognathic therapies nowadays
Among the participants included in this study, the four cephalometric indices of upper lip characteristics were normally distributed, and only upper lip thickness was not (Figure 3A)
Superior sulcus depth was negatively related to Class II (β = −0.195, 95% confidence interval (CI) −0.302 to −0.087; model 4), and positively related to Class III (β = 0.253, 95% CI 0.117 to 0.389; model 4)

Summary

Introduction

Profile esthetics is generally becoming one of the major objectives of patients seeking orthodontic or orthognathic therapies nowadays. Skeletal patterns are reflections of the relative position of maxilla and mandible, which can be evaluated in the sagittal and vertical dimension, respectively. It was shown that facial soft tissue thickness, especially in the chin area, varied among different vertical developmental patterns, which was smaller in hyperdivergent patterns [6,7]. This study is aimed to evaluate the association between upper lip characteristics (ULCs) and skeletal patterns (SPs). Confounders including demography, malocclusion, upper incisors, and upper lips were adjusted by multivariate linear regression to identify the association between ULCs and SPs. Group differences were evaluated with analysis of variance and Chi-square test. ULCs were significantly different in various sagittal, vertical, and combined SPs. Superior sulcus depth was negatively related to Class II, and positively related to Class III and the hypodivergent pattern after adjusted by confounders. Conclusions: ULCs significantly varied among different SPs, while only superior sulcus depth was independently associated with SPs, indicating superior sulcus depth is the only ULC that might be significantly corrected by intervention of skeletal growth

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Discussion

Conclusion