Relationship between the Position of the Incisors and the Thickness of the Soft Tissues in the Upper Jaw: Cephalometric Evaluation

Abstract

Aim:The aim of this study is to verify if the thickness of soft tissues and inclination of the incisors have some relation with profile, to analyze its relevance considering these two parameters separately and to screen how the combination of different inclinations and different thickness can generate different facial patterns. Materials and methods: The study was performed on 47 Caucasian patients aged between 6 years and 16 years of divided into 24 males and 23 females. None of the patients presented craniofacial changes of syndromic nature. All patients presented a value of SNA in between 80° and 84°. The inclination of the upper incisor related to the bispinal plane was between 104° and 116°. Each radiograph has been digitized or analyzed directly in digital format. To analyze the relationships between soft tissues and position of the incisors using various cephalometric measures and statistical methodology were used. Results: Analysing the general correlation between all the cephalometric parameters considered, the results found show that the thickness of the tissues had an effect in modifying the aesthetic profile with respect to the position of the incisors. The cephalometric parameters related to the esthetic profile of the maxilla are all linked by strong correlations, especially correlation between SU, ULA and LS were very high. The differences between the means were statistically significant for different groups. Using the values of Mx1 and thickness of the lip as independent variables, while the LS, SU, ULA and NLA values as dependent variables all results are significant with respect to the prediction p < 0.05. Conclusion: Thickness of the soft tissues showed a significant influence on the profile with respect to the position of the incisors. Clinical significance: Data obtained highlighted that thickness of the soft tissues must be taken into account before starting an orthodontic treatment in order to obtain best aesthetic results.

Network analysis of three-dimensional hard-soft tissue relationships in the lower 1/3 of the face: Skeletal Class I-normodivergent malocclusion versus Class II-hyperdivergent malocclusion

“…However, many previous studies [4,5,7,11,12,13,14] have analysed patients with different skeletal types as a whole when looking for the morphological mechanism of soft tissues or making predictions. This might be one of the reasons for their limited accuracy.…”

“…Previous studies concerning skeletal Class II hyperdivergent malocclusion have been carried out, most of which were two-dimensional (2D) analysis using lateral cephalograms [4,5,6,7,8,9,10,11,12,13,14]. Kasai K [4] reported that the vertical dimension of the lower facial height and the position of the lower incisors were associated with the thickness of the upper-lip vermilion and soft tissue B.…”

“…It is well known that the relationship between craniomaxillofacial (CMF) hard and soft tissues is very complicated. Previous studies used correlation analysis or multiple regression analysis [4,5,6,10,11,12,13,14] to learn the relationship between soft and hard tissues, but the overall relationship of the CMF system could not be explored or visualized. For now, the most advanced arti cial intelligence algorithm [7] for predicting soft tissue contour from hard tissue shape calculates only two line distances (the distance between labrale superius or labrale inferius to the esthetics plane), which essentially predicts the position of merely two points, and cannot re ect the complex soft tissue contour.…”

“…For now, the most advanced arti cial intelligence algorithm [7] for predicting soft tissue contour from hard tissue shape calculates only two line distances (the distance between labrale superius or labrale inferius to the esthetics plane), which essentially predicts the position of merely two points, and cannot re ect the complex soft tissue contour. In addition, most studies have focused on the correlation between lip thickness, length and hard tissue measurements due to the adoption of linear distance and angle for analysis [6,8,9,11,12,13,14]. However, the position of the soft tissue surface is more critical than the lip thickness.…”

Patterns of Facial Profile Preference in a Large Sample of Dental Students: A Cross-Sectional Study

“…We also found that an anteriorly shifted maxillary arch gained popularity toward the higher grades. The most probable explanation is that this is the effect of the position of the maxillary incisors, which is documented to have a significant effect on the esthetics of the facial profile [25]. Most studies explain this effect by the varying degrees of soft tissue displacement [26,27].…”