Three-dimensional photographic analysis of the face in European adults from southern Spain with normal occlusion: reference anthropometric measurements

Comparative analysis of 3D tomography based soft tissue rendering and Proface facial scanning systems in orthognathic surgery

PURPOSE

This study aimed to investigate the linear and angular differences in the nasolabial soft tissue in patients who underwent bimaxillary orthognathic surgery using two different three-dimensional imaging methods. Furthermore, the advantages, disadvantages, and limitations of these methods were determined after comparing the data obtained from the imaging methods used in the study.

MATERIALS AND METHODS

Preoperative (T0) and 6-months postoperative (T1) cone-beam computed tomography (CBCT) and three-dimensional facial scanning (3DFS) data from 22 patients who underwent maxillary advancement surgery were examined. The DICOM (Digital Imaging and Communications in Medicine) data (CBCT group) and ".obj" format images (3DFS group) of the patients were analyzed using Dolphin software (Dolphin Imaging®, Version 12, Chatsworth, CA, USA). The linear and angular soft tissue measurements were calculated after determining the reference anatomical landmarks for both groups.

RESULTS

Measurements with CBCT and 3DFS imaging methods were compared at T0, T1, and all measurements (T0+T1). No statistically significant difference was observed between the CBCT and 3DFS groups for five measurements performed at T0 and T0+T1, but statistically significant differences were observed between the groups for the other seven measurements. There was no statistically significant difference between the CBCT and 3DFS groups for six measurements at T1, but there were statistically significant differences between the groups for the other six measurements. After reviewing the postoperative differences in the nasolabial soft tissue, a statistically significant increase in four linear and one angular measurement in the 3DFS group was observed, and there was a statistically significant increase in two linear and two angular measurements in the CBCT group. Upon comparison of postoperative differences in soft tissue alterations, no statistically significant difference between the 3DFS group and the CBCT group were observed in any of the soft tissue measurements.

CONCLUSION

Orthognathic surgery has significant effects on nose width and upper lip morphology. Although both 3DFS and CBCT methods can be used to evaluate such effects, the results of the present study revealed differences in sensitivity and limitations between the two methods. Thus, surgical outcomes should be evaluated in consideration of the abovementioned parameters.

Photographic Nasal Soft Tissue Analysis From Preadolescence to Young Adulthood: Anthropometric Measurements

ABSTRACT

The nose has a tremendous effect on facial esthetics and overall facial harmony, accordingly it contributes to the physical appearance of individuals. The aim of this study is to establish sex-related nasal soft tissue norms for preadolescents, adolescents, and young adults in Anatolian population. A total of 300 volunteers (150 males and 150 females) with ages varying from 10 to 24 years were divided into 6 subgroups according to gender and educational status. The anthropometric measurements of the nose in preadolescent, adolescent, and young adult males and females were performed on digital photographs. A total of 16 nasal parameters, 13 linear and 3 angular measurements, were analyzed for sex-related variations. A significant sexual dimorphism was observed for nasofrontal and nasolabial angles in adolescent and young adult groups (P < 0.001, P = 0.011, and P = 0.007, respectively). All linear measurements of the nose were larger in males as compared to females, except for left alar thickness, which were similar between males and females in young adult group. Of the 16 nasal measurements, 13 were found to be sexually dimorphic in certain age groups (P < 0.05). In Anatolian population, the nasal shape and dimensions displayed significant sexual dimorphism in preadolescents, adolescents, and young adults. The average values of nasal soft tissue in this population could serve as a database for the planning of cosmetic and reconstructive rhinoplasty in the pediatric and adult population and obtaining the desired outcomes.

Updating Standards of Facial Growth in Romanian Children and Adolescents Using the Anthropometric Method-A Pilot Study

The anthropometric method is an important tri-dimensional and non-invasive assessment instrument for accurate diagnosis in paedodontics, orthodontics, and other medical fields. Our aim was to propose a technique that is accessible for clinicians and to determine the reference values for Romanian children and adolescents for the facial parameters selected. We proposed three basic instruments: a plastic compass, a ruler, and a digital caliper. Eighty-five children and adolescents (62% girls and 38% boys), aged between 3.5 and 14.5 years, were included in the study. We selected eight transversal, 12 vertical, and three sagittal measurements. Facial indices, according to Farkas L.G., were directly determined. The correlations between facial and general growth parameters, using Pearson correlation coefficient, for the entire sample were significant, direct, and strong for the following: Zy-Zy, Go-Go, N-Gn, N-Sn, Sto-Gn, Tr-Gn, Tr-Sn, Tr-Tr (r = 0.526–0.925, p < 0.001), and insignificant for Sn-Sto (r = 0.099–0.124, p > 0.354). The highest correlation coefficient is exhibited by Tr-Gn (r = 0.893 with height and r = 0.925 with weight). When performing a gender related comparison, we noticed that the vertical and transversal linear parameters and some facial indices are increased in boys (p < 0.05), depending on the age group. The simplified anthropometric technique represents an accessible method to every clinician, bringing important information related to dentofacial growth, diagnosis, and treatment planning in dentistry.

Automatic 3D dense phenotyping provides reliable and accurate shape quantification of the human mandible

Automatic craniomaxillofacial (CMF) three dimensional (3D) dense phenotyping promises quantification of the complete CMF shape compared to the limiting use of sparse landmarks in classical phenotyping. This study assesses the accuracy and reliability of this new approach on the human mandible. Classic and automatic phenotyping techniques were applied on 30 unaltered and 20 operated human mandibles. Seven observers indicated 26 anatomical landmarks on each mandible three times. All mandibles were subjected to three rounds of automatic phenotyping using Meshmonk. The toolbox performed non-rigid surface registration of a template mandibular mesh consisting of 17,415 quasi landmarks on each target mandible and the quasi landmarks corresponding to the 26 anatomical locations of interest were identified. Repeated-measures reliability was assessed using root mean square (RMS) distances of repeated landmark indications to their centroid. Automatic phenotyping showed very low RMS distances confirming excellent repeated-measures reliability. The average Euclidean distance between manual and corresponding automatic landmarks was 1.40 mm for the unaltered and 1.76 mm for the operated sample. Centroid sizes from the automatic and manual shape configurations were highly similar with intraclass correlation coefficients (ICC) of > 0.99. Reproducibility coefficients for centroid size were < 2 mm, accounting for < 1% of the total variability of the centroid size of the mandibles in this sample. ICC’s for the multivariate set of 325 interlandmark distances were all > 0.90 indicating again high similarity between shapes quantified by classic or automatic phenotyping. Combined, these findings established high accuracy and repeated-measures reliability of the automatic approach. 3D dense CMF phenotyping of the human mandible using the Meshmonk toolbox introduces a novel improvement in quantifying CMF shape.

Measurement of three-dimensional changes in lip vermilion in adult female patients after orthodontic extraction: a retrospective longitudinal study

Background

3D facial scanning has changed the way facial aesthetic is evaluated and has numerous advantages for facial analysis. The specific relationship between lip vermilion morphological changes after orthodontic extraction treatment has not been fully explained. The objective of this study was to evaluate 3D morphological changes after orthodontic extraction treatment in lip vermilion of adult females with dentoalveolar protrusion using a structured light-based scanner.

Methods

Forty-two female subjects (25.2 ± 1.9 years) were recruited as the treatment group; these patients had undergone extraction treatment and achieved better sagittal profiles. Twenty female subjects (25.5 ± 2.1 years) were enrolled in the non-treatment group; these patients did not require any orthodontic treatment. The follow up time for the treatment group was more than 24 months and for the non-treatment group was more than 12 months. 3D facial scans were captured using 3D CaMega. Six landmarks (Ls, Li, R.Chp, L.Chp, R.Ch, and L.Ch), three linear measurements (mouth height, philtrum width, and mouth width), and three area measurements (upper, lower, and total vermilion area) were measured. The spatial deviations of three volumetric measurements (upper, lower, and total vermilion) were constructed for quantitative analysis. Color-coded displacement map were constructed for visualization of the soft-tissue displacement as qualitative evaluation.

Results

Mouth height and philtrum width decreased (-0.93 mm and − 1.08 mm, respectively) significantly (p = 0.008 and p = 0.027, respectively), and no significant (p = 0.488) change in mouth width was observed in the treatment group. The lower and total vermilion surface areas decreased (-51.00mm² and − 69.82mm², respectively) significantly (p = 0.003 and p = 0.031, respectively) in the treatment group, but no statistically significant (p = 0.752) change was detected in the upper vermilion. In the treatment group, significant retractions were observed in the color-coded displacement map, and three volumetric measurements of vermilion changed significantly (p = 0.012, p = 0.001 and p = 0.004, respectively). Significant differences were found between the treatment group and the non-treatment group in the linear, area and volumetric measurements.

Conclusions

This study established a method for qualitative and quantitative evaluation of the lip vermilion. Significant 3D retraction of the lip vermilion after the extraction treatment was found, with morphological variation between upper and lower vermilion.

Effect of aging and body characteristics on facial sexual dimorphism in the Caucasian Population

Aim

The aim of this study was to quantify gender-specific facial characteristics in younger and older adults and to determine how aging and body characteristics, such as height and body-mass index (BMI), influence facial sexual dimorphism.

Methods

The cohort study included 90 younger adults of Caucasian origin (average age of 45 females 23.2 ± 1.9 and 45 males 23.7 ± 2.4 years) and 90 older adults (average age of 49 females 78.1 ± 8.1 and 41 males 74.5 ± 7.7 years). Three-dimensional facial scans were performed with an Artec MHT 3D scanner. The data were analyzed using the software package Rapidform^®. The parameters to evaluate facial symmetry, height, width, profile, facial shape, nose, eyes and mouth characteristics were determined based on 39 facial landmarks. Student’s t-test was used to calculate the statistical differences between the genders in the younger and older adults and a multiple-linear-regression analysis was used to evaluate the impact of gender, age, body-mass index and body height.

Results

We found that the female faces were more symmetrical than the male faces, and this was statistically significant in the older adults. The female facial shape was more rounded and their faces were smaller, after normalizing for body size. The males had wider mouths, longer upper lips, larger noses and more prominent lower foreheads. Surprisingly, we found that all the gender-dependent characteristics were even more pronounced in the older adults. Increased facial asymmetry, decreased facial convexity, increased forehead angle, narrower vermilions and longer inter-eye distances occurred in both genders during aging. An increased BMI was associated with wider faces, more concave facial profiles and wider noses, while greater body height correlated with increased facial heights and wider mouths.

Conclusion

Facial sexual dimorphism was confirmed by multiple parameters in our study, while the differences between the genders were more pronounced in the older adults.