3D stereophotogrammetry versus traditional craniofacial anthropometry: Comparing measurements from the 3D facial norms database to Farkas's North American norms

Three-Dimensional Geometric Morphometric Characterization of Facial Sexual Dimorphism in Juveniles

Background: The characterization of facial sexual dimorphic patterns in healthy populations serves as valuable normative data to tailor functionally effective surgical treatments and predict their aesthetic outcomes and to identify dysmorphic facial traits related to hormonal disorders and genetic syndromes. Although the analysis of facial sexual differences in juveniles of different ages has already been investigated, few studies have approached this topic with three-dimensional (3D) geometric morphometric (GMM) analysis, whose interpretation may add important clinical insight to the current understanding. This study aims to investigate the location and extent of facial sexual variations in juveniles through a spatially dense GMM analysis. Methods: We investigated 3D stereophotogrammetric facial scans of 304 healthy Italians aged 3 to 18 years old (149 males, 155 females) and categorized into four different age groups: early childhood (3-6 years), late childhood (7-12 years), puberty (13-15 years), and adolescence (16-18 years). Geometric morphometric analyses of facial shape (allometry, general Procrustes analysis, Principal Component Analysis, Procrustes distance, and Partial Least Square Regression) were conducted to detail sexually dimorphic traits in each age group. Results: The findings confirmed that males have larger faces than females of the same age, and significant differences in facial shape between the two sexes exist in all age groups. Juveniles start to express sexual dimorphism from 3 years, even though biological sex becomes a predictor of facial soft tissue morphology from the 7th year of life, with males displaying more protrusive medial facial features and females showing more outwardly placed cheeks and eyes. Conclusions: We provided a detailed characterization of facial change trajectories in the two sexes along four age classes, and the provided data can be valuable for several clinical disciplines dealing with the craniofacial region. Our results may serve as comparative data in the early diagnosis of craniofacial abnormalities and alterations, as a reference in the planning of personalized surgical and orthodontic treatments and their outcomes evaluation, as well as in several forensic applications such as the prediction of the face of missing juveniles.

An in-vivo study on the effect of head orientation in the measurement of anthropometric points in stereophotogrammetry

BACKGROUND

It is well known that in bidimensional photography the orientation of the head is fundamental to obtain a correct reproduction of the subject. Even minimal errors in yaw, roll and pitch of the head can be cause of unreliability of the photography itself. This is not the case in three-dimensional photography in which head positioning may have no influence on the reliability of the results since on the computer the 3D reconstruction of the face can be oriented as desired, allowing any small errors to be corrected. The authors, in a previous in-vitro study, demonstrated this using a mannequin of the head. In the present study, the Authors repeat the study in vivo to verify any differences.

METHODS

Seventeen anthropometric points were marked on the face of a young adult female (26 years old) with eyeliner. Images of the face were then acquired with a stereo-photogrammetric system (Face Shape 3D MaxiLine) in natural head position and with varying degrees of roll, pitch and yaw. The anthropometric points marked on the skin were then recognized and marked on a digital software (Viewbox, dHAL Software, 6 Menandrou Street, Kifissia 14561, Greece) on each individual image. 14 linear distances between these points were measured using the same software.

RESULTS

The linear distances of these points in the stereophotos taken at centered positions were then compared with those taken with different degrees of roll, pitch and yaw. This study confirms previous results obtained in vitro regarding the presence of areas of non-equivalence (P<0.05) when comparing the frontal and lateral regions of the face at various angles.

CONCLUSIONS

However, it introduces important suggestions on the collection of data from specific anthropometric points. If these points are to be assessed, the medical staff will have to take special precautions to obtain reliable images.

Photogrammetry is a useful tool to assess the aesthetic outcome after excision and reconstruction of the nose skin tumors

BACKGROUNDOBJECTIVE

Post-oncological nasal reconstruction presents both aesthetic and functional challenges. While established methods exist for quantitatively evaluating functional results following surgery, equivalent systems for assessing aesthetic outcomes are lacking. Three-dimensional (3D) photogrammetry, already used in maxillofacial and orthodontic surgery for aesthetic evaluation, overcomes some limitations of traditional methods like direct anthropometry. However, its applicability in oncological facial reconstruction has not yet been explored. In our study, we applied the 3dMDtrio™ system for the quantitative analysis of line and surface modifications following nasal reconstruction.

METHODS

We conducted a prospective observational study enrolling patients with skin neoplasms located on the nose undergoing surgical excision and reconstruction. Using the 3dMDtrio™ system, we measured the dimensions and projections of nasal surfaces and the positions of specific landmarks before and after surgery. The surface measurements were then correlated with aesthetic evaluations performed by three plastic surgeons, not involved in the procedure, using a 5-point Likert scale.

RESULTS

We included 33 patients with a mean age of 71 years, ranging from 40 to 94. We obtained complete documentation of all postoperative measurements for 21 patients. We observed significant changes in the positions of the landmarks post-surgery, limited to the right ala and nasion. The average nasal surface area was 4674.41 mm2 ± 477.24 mm2 before surgery and 4667.95 mm2 ± 474.12 mm2 after surgery, with no significant discrepancies. The evaluation using the Likert scale revealed an average score of 3.04 ± 0.48, with a significant negative correlation to the measured surface changes.

CONCLUSION

Our findings suggest that 3D photogrammetry can be considered a valid method for objectively assessing volumetric changes associated with post-oncological nasal reconstructive surgery.

Anthropometry and Current Aesthetic Concept of the Lower Third of the Face and Lips in Caucasian Adult Population: A Systematic Review and Meta-Analysis

BACKGROUND

The lack of standardization of the norms and aesthetic concept of the lower third of the face and lips creates challenges in reconstructive surgery and aesthetic procedures. A large-scale, anthropometric measurements summary poses an alternative for establishing universal patterns.

METHODS

A systematic review was conducted by searching PubMed, Embase, Google Scholar and Web of Science using keywords: lip, face, aesthetics, beauty, anthropometry and Caucasian. Seventy records were included in the review and checked in detail in terms of available data.

RESULTS

The study contains a meta-analysis of twelve parameters with sufficient quantitative data-lip width, nose width, facial width, lower third of the face height, midline mandible height, total height of the upper and lower lip, upper and lower vermilion height, cutaneous upper lip height and nasolabial and mentolabial angle.

CONCLUSIONS

The review provides a detailed database of primary anthropometric studies of lips and perioral regions of the healthy Caucasian population. The attractiveness of the region is focused on uniformity of proportions. Notably, results acquired with different methods of measurement are not interchangeable. Despite many published anthropometric studies, systems for conducting the measurements and reporting the results are not sufficiently unified to quantitatively assess meticulous key aesthetic clinical parameters.

LEVEL OF EVIDENCE I

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine Ratings, please refer to Table of Contents or online Instructions to Authors www.springer.com/00266 .

Age-related changes of the periocular morphology: a two- and three-dimensional anthropometry study in Caucasians

PURPOSE

To determine age-and sex-related changes in periocular morphology in Caucasians using a standardized protocol.

METHODS

Healthy Caucasian volunteers aged 18-35 and 60-90 years old were recruited from the Department of Ophthalmology, Faculty of Medicine and University Hospital, Cologne, between October 2018 and May 2020. Volunteers with facial asymmetry, facial deformities, history of facial trauma, facial surgery, botox injection, eyelid ptosis, strabismus, or nystagmus, were excluded. Standardized three-dimensional facial photos of 68 young volunteers and 73 old volunteers were taken in this clinical practice. Position changes of endocanthion, pupil center, and exocanthion were analyzed in different age and gender groups, including palpebral fissure width (PFW): distance between endocanthions (En-En), pupil centers (Pu-Pu), exocanthions (Ex-Ex), endocanthion and nasion (En-Na), pupil center and nasion (Pu-Na), exocanthion and nasion (Ex-Na), endocanthion and pupil center (Pu-En), exocanthion and pupil center (Pu-Ex), and palpebral fissure inclination (PFI); angle of endocanthions to nasion (En-Na-En), pupils to nasion (Pu-Na-Pu), exocanthions to nasion (Ex-Na-Ex); endocanthion inclination (EnI), and exocanthion inclination (ExI).

RESULTS

PFW, En-En, Ex-Na, Pu-Ex, PFI, ExI, and Ex-Na-Ex were significantly different between the young and old groups (p ≤ 0.004). There were sex-related differences in PFW, Ex-Ex, En-Na, Pu-Na, Ex-Na, Pu-En, PFI, and EnI between both groups (p ≤ 0.041).

CONCLUSION

The position change of the pupil is minimal relative to age; it is preferred to establish the reference plane to describe periocular changes. The endocanthion tends to move temporally and inferiorly, while the exocanthion tends to shift nasally and inferiorly with age.

Expanding the Classic Facial Canons: Quantifying Intercanthal Distance in a Diverse Patient Population

Background:

The intercanthal distance (ICD) is central to our perception of facial proportions, and it varies according to gender and ethnicity. Current standardized reference values do not reflect the diversity among patients. Therefore, the authors sought to provide an evidence-based and gender/ethnicity-specific reference when evaluating patients’ ICD.

Methods:

As per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic search of PubMed, Medline, and Embase was carried out for studies reporting on the ICD. Demographics, study characteristics, and ICDs were extracted from included studies. ICD values were then pooled for each ethnicity and stratified by gender. The difference between men and women, and that across ethnicities and measurement types were compared by means of independent sample t-test and one-way ANOVA (SPSS v.24).

Results:

A total of 67 studies accounting for 22,638 patients and 118 ethnic cohorts were included in this pooled analysis. The most reported ethnicities were Middle Eastern (n = 6629) and Asian (n = 5473). ICD values (mm) in decreasing order were: African 38.5 ± 3.2, Asian 36.4 ± 1.6, Southeast Asian 32.8 ± 2.0, Hispanic 32.3 ± 2.0, White 31.4 ± 2.5, and Middle Eastern 31.2 ± 1.5. A statistically significant difference (P < 0.05) existed between all ethnic cohorts, between genders among most cohorts, and between most values stratified by measurement type.

Conclusions:

Our standards of craniofacial anthropometry must evolve from the neoclassical canons using White values as references. The values provided in this review can aid surgeons in appreciating the gender- and ethnic-specific differences in the ICD of their patients.

Longitudinal composite 3D faces and facial growth trends in children 6-11 years of age using 3D cephalometric surface imaging

BACKGROUND

Normative craniofacial anthropometry provides clinically important reference values used in the treatment of craniofacial conditions. Few objective datasets of normative data exist for children.

AIM

To establish normative data regarding craniofacial morphology changes with growth in children.

SUBJECTS AND METHODS

3D surface images of the same group of healthy children aged 6 - 11 years old recruited from a Dallas school were taken annually between the years 2015 - 2020. Composite 3D cephalometric faces were created for boys and girls of each age. General and craniofacial anthropometric measurements were compared.

RESULTS

Seven hundred ninety one individual stereophotogrammetric acquisitions were used (400 boys, 391 girls) taken from 180 children. Linear facial, orbital, nasal, and oral anthropometric measurements revealed a consistent increase in magnitude with age. Composite 3D face comparisons revealed prominent vertical and anteroposterior growth trends in the lower and upper facial regions.

CONCLUSION

This study presents a longitudinal 3D control dataset of the same group of children over a 6-year period that can serve as reference norms for facial growth values and trends in children aged 6-11 years. The composite 3D normative faces are available for clinical and research purposes upon request, which may be interrogated and measured according to user need and preference.

A novel approach quantifying the periorbital morphology: A comparison of direct, 2-dimensional, and 3-dimensional technologies

BACKGROUND

The measurement of anatomical structures is critical in plastic and reconstructive surgery. However, few detailed and standardized measurements have been widely used in the periorbital region. This study aimed to evaluate the feasibility of a novel detailed and standardized protocol with 2D and 3D technologies, and explore the relationship between them and direct measurements.

METHODS

Fifty healthy Caucasians (100 eyes) between 20 and 68 years old were recruited and captured for 3D photographs by VECTRA M3 3D Imaging System. Subsequently, 24 landmarks were located on each 3D photographs following a standardized protocol, and then 19 linear and 3 angular periorbital variables were measured. Furthermore, two-dimensional (2D) and direct measurements were conducted on each subject and compared with 3D measurements and one another.

RESULTS

The grand r means across all measurements were 0.77, 0.78, and 0.88 for direct vs. 2D values, direct vs. 3D values, and 3D vs. 2D values, respectively. The mean absolute differences were 1 mm (ranging from 0.2 mm to 3.7 mm) between direct and 3D measurements, 1 mm (ranging from 0.04 mm to 2.4 mm) between direct and 2D measurements, and 1 mm and 6.6° (ranging from 0.04 mm or 0.5° to 3 mm or 12.8°) between 2D and 3D measurements.

CONCLUSIONS

This study verified the feasibility of this detailed and standardized landmark localization protocol for assessing the periorbital morphology with 2D and 3D technologies. This protocol may work as a bridge communicating with all studies involving any of the three technologies in the future.

3D Analysis of Facial Morphology of a Colombian Population Compared to Adult Caucasians

Objective:  The purpose of this study involves describing the facial morphology of a Colombian population with three-dimensional (3D) imaging, and comparing their facial morphology with the Caucasian to create a database for this ethnicity.

Materials and Methods:  The study, which included 135 subjects selected from the Valle University in Cali, Colombia, and 535 Caucasian subjects selected from the FaceBase–Data (1U01DE024449–01), was funded by the National Institute of Dental and Craniofacial Research. All images were taken in the natural head position (NHP) and captured using a stereo-photogrammetric camera system (3dMDface) to obtain a 3D image of each patient. The subjects were between 19 to 31 years of age, with a normal body mass index (BMI), and no craniofacial deformities. All images were plotted and analyzed using the 3dMDVultus software to calculate linear and angular measurements. Standard deviation (SD) and means were calculated for each measurement and analyzed using t -test for different samples.

Results:  The Hispanic population had wider eyes, more protruded upper and lower lips, wider face, and greater mandibular width. Caucasian females had a more acute full profile, larger middle third, and less protrusive lips. Understanding the facial morphology of different populations would help to establish a better diagnosis and treatment planning for each ethnicity.

Conclusions:  From this study, the following conclusions may be drawn:

1. The mean values of Colombian males showed greater measurements than females in the majority of measurements.

2. Caucasian females had a more acute full profile, larger middle and lower third, and less protrusive lips.

3. This study showed significant ethnic differences in the linear and angular measurements, showing us the importance of considering these findings in the diagnosis and treatment planning when a Hispanic population is involved. Soft tissue values should reflect the norms according to each ethnic population in order to achieve treatment goals.

Integration of digital maxillary dental casts with 3D facial images in orthodontic patients

OBJECTIVE

To evaluate three-dimensional (3D) accuracy and reliability of nonradiographic dentofacial images integrated with a two-step method.

METHODS

3D facial images, cone-beam computed tomography (CBCT) images and digital maxillary dental casts were obtained from 20 pre-orthodontic subjects. Digital dental casts were integrated into 3D facial images using a two-step method based on the anterior tooth area. 3D coordinate values of five dental landmarks were identified in both dentofacial images and CBCT images. The accuracy of the integration method was assessed with paired t-tests between dentofacial images and CBCT-based reference standards. Intraclass correlation coefficients (ICCs) were assessed for the reliability of dentofacial images and CBCT-based images. Analysis of variance and Kruskal-Wallis tests evaluated the accuracy of the method in different dimensions.

RESULTS

There was no statistical difference between dentofacial images and CBCT reference standards in both translational and rotational dimensions (P > .05). Translational mean absolute errors for full dentitions were within 0.42 mm and ICCs were over 0.998 in x, y, and z directions. Rotational mean absolute errors for full dentitions were within 0.92° and ICCs over 0.734 in pitch, yaw, and roll orientations. Integration errors were significantly greater in the first molar, z-translation, and pitch rotation (P < .05).

CONCLUSIONS

Integrating 3D dentofacial images with the two-step method is precise and acceptable for clinical diagnostics and scientific purposes. Errors were greater in the molar region, z-translation, and pitch rotation.

A Cross-Sectional Study to Understand 3D Facial Differences in a Population of African Americans and Caucasians

Objective The purpose of this cross-sectional retrospective study was to use three-dimensional surface imaging to determine gender dimorphism and facial morphological changes from adolescence to adulthood in African American and Caucasian populations.

Materials and Methods Three-dimensional images were captured and the total sample size included 371 subjects. Images were combined using Rapidform 2006 Plus Pack 2 software to produce a male and female facial average for each population. Comparisons were conducted within the following categories: (1) gender comparison within each race, (2) adult and adolescent comparison within each race, and (3) adult and adolescent comparison between the races.

Results Adolescent gender comparisons within each race showed high percentages of similarity. However, adult females in both races showed more prominent periorbital, malar, and nasolabial regions and less prominent lower forehead, nose, and lower face compared with adult males of the same race. African American adult females showed increase in length and width of the face, increased nasal tip projection, and decreased periorbital regions compared with African American adolescent females. Welsh adult females had an increase in the nose and chin projection compared with Welsh adolescent females. Adult males of both races had increase in nose and chin projection, increase in length and width of the face, and decreased periorbital, malar, and nasolabial regions compared with adolescent males of the same race. African American adolescents had a wider alar base, more protrusive lips, and periorbital regions, and less prominent nose and chin compared with the Welsh adolescents. African American adults also had a wider alar base; more protrusive lips and periorbital regions; a broader face; and more retrusive chin, nose, nasolabial region; and lower forehead compared with Welsh adults.

Conclusions Few differences were noted between genders within the same racial groups during adolescence. However, changes became more distinct in adulthood. From adolescence to adulthood, facial morphologies were similarly matched within the gender for females; however, there were significant changes for males. Lastly, facial morphology patterns tend to be established early in life.