Three-dimensional comparison of facial morphology in white populations in Budapest, Hungary, and Houston, Texas

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 .

Face Structure, Beauty, and Race: A Study of Population Databases Using Computer Modeling

Background

Understanding the differences in facial shapes in individuals from different races is relevant across several fields, from cosmetic and reconstructive medicine to anthropometric studies.

Objectives

To determine whether there are features shared by the faces of an aesthetic female face database and if they correlate to their racial demographics using novel computer modeling.

Methods

The database was formed using the "top 100 most beautiful women" lists released by "For Him Magazine" for the last 15 years. Principal component analysis (PCA) of 158 parameters was carried out to check for clustering or racial correlation with these clusters. PCA is a machine-learning tool used to reduce the number of variables in a large data set, allowing for easier analysis of the data while retaining as much information as possible from the original data set. A review of the literature on craniofacial anthropometric differences across ethnicities was also undertaken to complement the computer data.

Results

Two thousand eight hundred and seventy aesthetic faces formed the database in the same racial proportion as 10,000 faces from the general population as a baseline. PCA clustering illustrated grouping by latent space parameters for facial dimensions but showed no correlation with racial demographics. There was a commonality of facial features within the aesthetic cohort, which differed from the general population. Fourteen papers were included in the review which contained 8142 individuals.

Conclusions

Aesthetic female faces have commonalities in facial features regardless of racial demographic, and the dimensions of these features vary from the baseline population. There may even be a common human aesthetic proportion that transcends racial boundaries, but this is yet to be elucidated.

Level of Evidence 5

Exploring regional aspects of 3D facial variation within European individuals

Facial ancestry can be described as variation that exists in facial features that are shared amongst members of a population due to environmental and genetic effects. Even within Europe, faces vary among subregions and may lead to confounding in genetic association studies if unaccounted for. Genetic studies use genetic principal components (PCs) to describe facial ancestry to circumvent this issue. Yet the phenotypic effect of these genetic PCs on the face has yet to be described, and phenotype-based alternatives compared. In anthropological studies, consensus faces are utilized as they depict a phenotypic, not genetic, ancestry effect. In this study, we explored the effects of regional differences on facial ancestry in 744 Europeans using genetic and anthropological approaches. Both showed similar ancestry effects between subgroups, localized mainly to the forehead, nose, and chin. Consensus faces explained the variation seen in only the first three genetic PCs, differing more in magnitude than shape change. Here we show only minor differences between the two methods and discuss a combined approach as a possible alternative for facial scan correction that is less cohort dependent, more replicable, non-linear, and can be made open access for use across research groups, enhancing future studies in this field.

A CBCT Evaluation of Esthetic Preference Regarding the Perceived Facial Attractiveness of Young Korean Female Adults with a Normal Skeletal Pattern

The aim of this study was to determine the factors that affect esthetic preference regarding the perceived facial attractiveness of young Korean female adults with a normal skeletal pattern using cone-beam computed tomography (CBCT). After reorienting the CBCT images of 40 young Korean female adults, three-dimensional (3D) measurements were analyzed, and five 3D facial images were digitally constructed. A computer-based questionnaire was used to determine perceived facial attractiveness by scoring from 1 (very unattractive) to 10 (very attractive). Esthetic perception and the most influential facial view and component were examined and compared by orthodontists, general dentists, and laypeople to evaluate facial attractiveness. Compared to the unattractive group, the attractive group had significantly greater values for Pog-NB, L1SI-FH, U lip thickness, L lip-U lip, and Nasolabial angle, along with significantly lower values for U1SI-FH and Cant of U lip; the attractive group also had a more retruded U1MP (p < 0.01), L1MP (p < 0.01), U lip (p < 0.05), and L lip (p < 0.01) relative to N, as well as a more retruded U lip (p < 0.05) and L lip (p <0.001) relative to esthetic lines. Orthodontists and general dentists were more likely to consider the profile view. When evaluating facial attractiveness, orthodontists and laypeople more often focused on the lips and chin. When evaluating facial attractiveness, all evaluators showed a high esthetic preference for retroclination and retrusion of the incisors and lips, but there were some differences in how they perceived facial attractiveness. Therefore, the ultimate perception of facial attractiveness needs to be based on the esthetic perceptions of laypeople.

Contemporary Smile Design: An Orthodontic Perspective

Orthodontists play a vital role in the smile design of individuals. There are a variety of orthodontic goals and tooth movements that can be achieved to obtain the ideal smile that ultimately leads to the optimum esthetic outcomes. In this article, some methods and appliance systems to control and achieve the desired tooth movements are described and illustrated.

Three-dimensional evaluation of soft tissues in hyperdivergent skeletal class II females in Guangdong

Objectives

To establish the three-dimensional facial soft tissue morphology of adolescent and adult females in the Guangdong population and to study the morphological characteristics of hyperdivergent skeletal class II females in Guangdong compared with that of normodivergent class I groups.

Materials and methods

The 3dMDface system was used to capture face scans of 160 patients, including 45 normal and 35 hyperdivergent skeletal class II adolescents (aged 11–14 years old) and 45 normal and 35 hyperdivergent skeletal class II adults (aged 18–30 years old). Thirty-two soft tissue landmarks were mapped, and 21 linear, 10 angular and 17 ratio measurements were obtained by 3dMDvultus analysis software. Data were assessed with a t-test of two independent samples between the normal adolescent and adult groups and between the normal and hyperdivergent skeletal class II groups.

Results

The linear measurements of the Guangdong adult females were larger than those of the adolescents in both Class I and Class II groups. However, the angular and ratio measurements had no significant difference. The vertical linear measurements were higher and the sagittal and transverse linear measurements were smaller in the hyperdivergent class II group (p < 0.05). The soft tissue ANB angle, chin-lip angle, and mandibular angle were significantly larger and the soft tissue facial convexity angle and nasal convexity angle were significantly smaller in the hyperdivergent class II group (p < 0.05). Additionally, there were significant differences in the ratio measurements between the hyperdivergent class II groups and the control groups (p < 0.05).

Conclusions

The three-dimensional facial morphology of Guangdong adolescent and adult females was acquired. The facial soft tissue measurements of the adults were higher in the three dimensions except for the facial convexity and proportional relationships which were similar, suggesting that the growth pattern remained the same. The three-dimensional facial soft tissue features of hyperdivergent skeletal class II were characterized by the terms “long, convex, and narrow”. Three-dimensional facial measurements can reflect intrinsic hard tissue characteristics.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12880-022-00782-w.

Two- and Three-Segment Surgically Assisted Rapid Maxillary Expansion: A Clinical Trial

BACKGROUND

The literature shows no consensus on whether two- or three-segment surgically assisted rapid maxillary expansion is the best operative technique.

METHODS

The present clinical trial was designed to compare the outcome of two- and three-segment osteotomy surgically assisted rapid maxillary expansion. Thirty-two adult patients with transverse maxillary deficiency greater than or equal to 5 mm were randomly assigned to two- and three-segment groups (n = 16). Dimensional and psychological assessments (Oral Health Impact Profile and Brazilian Orthognathic Quality of Life Questionnaire) were carried out before surgical intervention and at one of the following time points: completion of expansion, removal of expanding device, 6 months after completion of expansion, or 10 months after completion of expansion. Dimensional assessments for asymmetric expansion of the maxilla and for changes in the area and volume of the palatine vault were performed on digital data from tomographic and laser scanning with the aid of an engineering inspection software.

RESULTS

No statistically significant differences were found in asymmetry or stability outcomes between groups. The psychological benefit provided by the three-segment technique did not spread through the domains of the quality-of-life questionnaires.

CONCLUSIONS

The current findings suggest that three-segment surgically assisted rapid maxillary expansion outcomes do not exceed those obtained with its two-segment counterpart regarding symmetry of maxillary expansion and stability of area and volume of the palatine vault. Furthermore, psychological nuances evidenced in two- and three-segment groups with the tools used play a limited, short-lasting role, or a specific, more sensitive assessment tool needs to be developed.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

Population affinity and variation of sexual dimorphism in three-dimensional facial forms: comparisons between Turkish and Japanese populations

Examining the extent to which sex differences in three-dimensional (3D) facial soft tissue configurations are similar across diverse populations could suggest the source of the indirect evolutionary benefits of facial sexual dimorphism traits. To explore this idea, we selected two geographically distinct populations. Three-dimensional model faces were derived from 272 Turkish and Japanese men and women; their facial morphologies were evaluated using landmark and surface-based analyses. We found four common facial features related to sexual dimorphism. Both Turkish and Japanese females had a shorter lower face height, a flatter forehead, greater sagittal cheek protrusion in the infraorbital region but less prominence of the cheek in the parotid-masseteric region, and an antero-posteriorly smaller nose when compared with their male counterparts. The results indicated the possible phylogenetic contribution of the masticatory organ function and morphogenesis on sexual dimorphism of the human face in addition to previously reported biological and psychological characteristics, including sexual maturity, reproductive potential, mating success, general health, immune response, age, and personality.

Nasolabial shape and aesthetics in unilateral cleft lip and palate: an analysis of nasolabial shape using a mean 3D facial template

The aim of this study was to determine the amount of deviation in nasolabial shape in patients with a cleft compared with an average non-cleft face, and to assess whether this difference is related to nasolabial aesthetics. Three-dimensional stereophotogrammetric images of 60 patients with a unilateral cleft were used. To quantify shape differences, four average non-cleft faces were constructed from stereophotogrammetric images of 141 girls and 60 boys. Three-dimensional shape differences were calculated between superimposed cleft faces and the average non-cleft face for the same sex and age group. Nasolabial aesthetics were rated with the modified Asher-McDade Aesthetic Index using a visual analogue scale (VAS). Mean VAS scores ranged from 51.44 to 60.21 for clefts, with lower aesthetic ratings associated with increasing cleft severity. Shape differences were found between cleft faces and the average non-cleft face. No relationship was found for the VAS, age, and sex, except that a lower VAS was related to a higher nose and lip distance between the superimposed cleft and average non-cleft faces for nasal profile (P= 0.02), but the explained variance was low (R²=0.066). In conclusion, except for nasal profile, nasolabial aesthetics were not influenced by the extent of shape differences from the average non-cleft face.

Depiction of ethnic facial aging by forensic artists and preliminary assessment of the applicability of facial averages

Many characteristics of facial aging are common to all. The age of their onset and which characteristics tend to predominate varies among individuals depending on many factors including their genetic makeup, life experiences, environment in which they live, and the regional, ethnic, or socially perceived group to which they belong. Forensic artists are often asked to provide sketches, 2D or 3D digital renderings, or sculptures representative of how an individual may appear at an older age based on a provided photograph, victim or witness description, and/or cranial remains. The challenge escalates when the subject is a member of a regional, ethnic, or other socially perceived group to which the artist has had little or no exposure. We describe aspects of adult facial aging that are of particular relevance to the forensic artist, applicable software tools, and pertinent facial databases, especially those emphasizing non-white populations. We demonstrate that facial averaging offers two key advantages to the artistic portrayal of facial aging: first, the technique requires relatively small reference databases from groups that may present logistical challenges to collect and second, that a facial average provides a useful representation of the gestalt of the age and ethnicity cohort to which a subject belongs. The artist may use an average along with other available information such as photo reference books, eyewitness descriptions, photos of immediate family members, and cranial structure to guide production of a facial composite drawing, digital age progression, or sculpture of the subject in question.

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.

A Comparison of 3D Facial Features in a Population from Zimbabwe and United States

OBJECTIVES

 The purpose of this study was to determine the differences in three-dimensional (3D) facial features in a population from Zimbabwe and the United States. In addition, this study seeks to establish an average facial template of each population allowing clinicians to treat patients according to their cultural esthetic perceptions.

MATERIALS AND METHODS

 Three hundred one subjects from Zimbabwe and the United States were carefully selected and recruited for the study. Each subject presented with a normal facial profile, no asymmetries, and normal body mass index. The 3D images were captured using the 3dMD cameras. All images were further separated into male and female groups of the respective populations and imported to a dedicated software for analysis.

STATISTICAL ANALYSIS

 The 3D facial images were constructed using Rapidform 6 software to recreate a composite facial average for each group representing a male and female average 3D face of Zimbabwean (Zim) and United States origin.

RESULTS

 The linear measurements showed that the maximum average distance between the Zim-M and Zim-F was 1.24 mm and the minimum distance between the African American (AA)-M and AA-F was 0.24 mm. This was the absolute distance. When the signed linear measurements were taken into consideration, the maximum average distance between Zim-F and AA-M was 1.22 mm and the least average distance between the Zim-M and AA-M was 0.22 mm. The absolute color histograms showed greatest similarity between the Zim-M and AA-M at 58% and the Zim-F had a 25 and 27% similarity with the AA-F and Zim-M, respectively.

CONCLUSION

 The Zim-F showed the most variable features with a broader face, prominent forehead, and retruded alar base compared with their male counterparts and the Zim-M showed a wider prominent malar/zygomatic region, and prominent lateral supraorbital regions. There was a high similarity of 58% between the Zim-M and the AA-M, with the Zim-M showing a more protrusive superciliary arches, and a lateral zygomatic region tapering to the root of the nose.

Evaluation of the 3dMDface system as a tool for soft tissue analysis

OBJECTIVES

To evaluate the accuracy of three-dimensional stereophotogrammetry by comparing values obtained from direct anthropometry and the 3dMDface system. To achieve a more comprehensive evaluation of the reliability of 3dMD, both linear and surface measurements were examined.

SETTING AND SAMPLE POPULATION

UCLA Section of Orthodontics. Mannequin head as model for anthropometric measurements.

MATERIAL AND METHODS

Image acquisition and analysis were carried out on a mannequin head using 16 anthropometric landmarks and 21 measured parameters for linear and surface distances. 3D images using 3dMDface system were made at 0, 1 and 24 hours; 1, 2, 3 and 4 weeks. Error magnitude statistics used include mean absolute difference, standard deviation of error, relative error magnitude and root mean square error. Intra-observer agreement for all measurements was attained.

RESULTS

Overall mean errors were lower than 1.00 mm for both linear and surface parameter measurements, except in 5 of the 21 measurements. The three longest parameter distances showed increased variation compared to shorter distances. No systematic errors were observed for all performed paired t tests (P<.05). Agreement values between two observers ranged from 0.91 to 0.99.

CONCLUSIONS

Measurements on a mannequin confirmed the accuracy of all landmarks and parameters analysed in this study using the 3dMDface system. Results indicated that 3dMDface system is an accurate tool for linear and surface measurements, with potentially broad-reaching applications in orthodontics, surgical treatment planning and treatment evaluation.

Three-Dimensional Anthropometric Evaluation of Facial Morphology

OBJECTIVES

The objectives of this study were to evaluate sexual dimorphism for facial features within Colombian and Mexican-American populations and to compare the facial morphology by sex between these 2 populations.

MATERIALS AND METHODS

Three-dimensional facial images were acquired by using the portable 3dMDface system, which captured 223 subjects from 2 population groups of Colombians (n = 131) and Mexican-Americans (n = 92). Each population was categorized into male and female groups for evaluation. All subjects in the groups were aged between 18 and 30 years and had no apparent facial anomalies. A total of 21 anthropometric landmarks were identified on the 3-dimensional faces of each subject. The independent t test was used to analyze each data set obtained within each subgroup.

RESULTS

The Colombian males showed significantly greater width of the outercanthal width, eye fissure length, and orbitale than the Colombian females. The Colombian females had significantly smaller lip and mouth measurements for all distances except upper vermillion height than Colombian males. The Mexican-American females had significantly smaller measurements with regard to the nose than Mexican-American males. Meanwhile, the heights of the face, the upper face, the lower face, and the mandible were all significantly less in the Mexican-American females. The intercanthal and outercanthal widths were significantly greater in the Mexican-American males and females. Meanwhile, the orbitale distance of Mexican-American sexes was significantly smaller than those of the Colombian males and females. The Mexican-American group had significantly larger nose width and length of alare than the Colombian group regarding both sexes. With respect to the nasal tip protrusion and nose height, they were significantly smaller in the Colombian females than in the Mexican-American females. The face width was significantly greater in the Colombian males and females.

CONCLUSIONS

Sexual dimorphism for facial features was presented in both the Colombian and Mexican-American populations. In addition, there were significant differences in facial morphology between these 2 populations.

Facial asymmetry in head and neck rhabdomyosarcoma survivors

INTRODUCTION

Radiotherapy is essential for achieving and maintaining local control in head and neck rhabdomyosarcoma (HNRMS) patients. However, radiotherapy may cause outgrowth disturbances of facial bone and soft tissue, resulting in facial asymmetry. The aim of this study was to develop a method to visualize and measure facial asymmetry in HNRMS survivors using three-dimensional (3D) imaging techniques.

METHODS

Facial deformity was evaluated in a multidisciplinary clinical assessment of 75 HNRMS survivors, treated with external beam radiotherapy (EBRT, n = 26) or Ablative surgery, MOulage brachytherapy, and REconstruction (AMORE, n = 49). Individual facial asymmetry was measured using 3D photogrammetry and expressed in a raw asymmetry index and a normalized sex-age-ethnicity-matched asymmetry signature weight. Facial asymmetry was also compared between British and Dutch controls and between survivors and their matched controls.

RESULTS

Facial asymmetry was more pronounced with increasing age (P < 0.01) in British controls compared with Dutch controls (P = 0.04). Survivors developed more facial asymmetry than matched controls (P < 0.001). The clinical assessment of facial deformity correlated with the raw asymmetry index (r = 0.60, P < 0.001).

DISCUSSION

3D imaging can be used for objective measurement of facial asymmetry in HNRMS survivors. The raw asymmetry index correlated with a clinical assessment of facial deformity. Comparisons between treatment groups seemed inappropriate given the differences in facial asymmetry between British and Dutch controls. In future studies, pretreatment images could act as matched controls for posttreatment evaluation.

[The third dimension of the face aging, improvement of its understanding]

OBJECTIVES

Over the past 30 years, surface imaging has made tremendous progress. Surgical management has also been subject of numerous technical and strategic developments. For a better understanding of the curative strategies of face aging, the authors have put into perspective the three-dimensional data acquired up to date.

METHOD

A review of the literature focused on the three-dimensional study of facial aging was carried out.

RESULTS

Thanks to the precision of new surface acquisition systems and larger patient cohorts, our understanding of surfaces and volumes is now much more accurate. 3D, particularly highlights the major impact of aging on the perioral area, which was up to now neglected compared to other facial areas.

CONCLUSION

A technical discussion is needed to identify the best techniques to correct the defects and provide a natural result for those anatomical areas that are heavily impacted by aging but not corrected in the final.

A three-dimensional soft tissue analysis of Class III malocclusion: a case-controlled cross-sectional study

OBJECTIVE

The present study used the optical surface laser scanning technique to compare the facial features of patients aged 8-18 years presenting with Class I and Class III incisor relationship in a case-control design.

MATERIALS AND METHODS

Subjects with a Class III incisor relationship, aged 8-18 years, were age and gender matched with Class I control and underwent a 3-dimensional (3-D) optical surface scan of the facial soft tissues.

RESULTS

Landmark analysis revealed Class III subjects displayed greater mean dimensions compared to the control group most notably between the ages of 8-10 and 17-18 years in both males and females, in respect of antero-posterior (P = 0.01) and vertical (P = 0.006) facial dimensions. Surface-based analysis, revealed the greatest difference in the lower facial region, followed by the mid-face, whilst the upper face remained fairly consistent.

CONCLUSION

Significant detectable differences were found in the surface facial features of developing Class III subjects.

Anthropometric Study of Three-Dimensional Facial Morphology in Malay Adults

OBJECTIVES

To establish the three-dimensional (3D) facial soft tissue morphology of adult Malaysian subjects of the Malay ethnic group; and to determine the morphological differences between the genders, using a non-invasive stereo-photogrammetry 3D camera.

MATERIAL AND METHODS

One hundred and nine subjects participated in this research, 54 Malay men and 55 Malay women, aged 20-30 years old with healthy BMI and with no adverse skeletal deviation. Twenty-three facial landmarks were identified on 3D facial images captured using a VECTRA M5-360 Head System (Canfield Scientific Inc, USA). Two angular, 3 ratio and 17 linear measurements were identified using Canfield Mirror imaging software. Intra- and inter-examiner reliability tests were carried out using 10 randomly selected images, analyzed using the intra-class correlation coefficient (ICC). Multivariate analysis of variance (MANOVA) was carried out to investigate morphologic differences between genders.

RESULTS

ICC scores were generally good for both intra-examiner (range 0.827-0.987) and inter-examiner reliability (range 0.700-0.983) tests. Generally, all facial measurements were larger in men than women, except the facial profile angle which was larger in women. Clinically significant gender dimorphisms existed in biocular width, nose height, nasal bridge length, face height and lower face height values (mean difference > 3mm). Clinical significance was set at 3mm.

CONCLUSION

Facial soft tissue morphological values can be gathered efficiently and measured effectively from images captured by a non-invasive stereo-photogrammetry 3D camera. Adult men in Malaysia when compared to women had a wider distance between the eyes, a longer and more prominent nose and a longer face.

Three-dimensional Analysis of Normal Facial Morphologies of Asians and Whites: A Novel Method of Quantitative Analysis

The purpose of this study is to compare 3-dimensional facial averages of Asians (Koreans and Chinese) and Houstonian white faces using a (3-dimensional) surface imaging system.

Facial anthropometric analysis of a healthy group of young Brazilian adults by means of stereophotogrammetry technique

Abstract Introduction: Anthropometry is the science responsible for measuring the weight, size, and proportions of the human body, providing valuable and objective insights into how to characterize phenotypic variation and dysmorphology. Among the newer methods for facial analysis, the stereophotogrammetry technique has shown excellent results given its use of a group of fast cameras that photograph subjects from multiple angles. Objective: The aims of the present study were: (1) to analyze the facial profile of a group of healthy young Brazilian adults, between 18 and 30 years of age, (2) to define common facial values among the subjects, (3) to create a database of facial measurements of a portion of this young healthy Brazilian population to be used in future works, and (4) to test the precision and repeatability of the Vectra M3® equipment. Material and method: Sixty healthy young Brazilian adults participated in the study, 30 males and 30 females. Temporary craniometrical landmarks were performed in soft tissue, and those subjects underwent image capturing by the stereophotogrammetry technique. Thirty landmarks were used to take the measurements (in mm) of 35 distances. The equipment repeatability was tested in 20% of the sample (i.e., 12 subjects). Result: The values between the first and second acquisitions were statistically (p<0.05) similar for all 35 distances analyzed. The findings allowed the creation of a reliable database containing facial distances of a portion of the young healthy Brazilian population. In addition, the distances Tr-N, N-Sn, Ls-Sto, Sto-Li, En[r]-En[l] and Prn-Sn were not statistically different for the group of men (GM) and the group of women (GW), while the other 29 distances were significantly greater in GM. Conclusion: The technique and methods employed in the study yielded objective analyses of the facial profile of this group of healthy young Brazilian adults, and the equipment Vectra M3® showed a high level of precision and repeatability.

Does powdering of the dentition increase the accuracy of fusing 3D stereophotographs and digital dental casts

OBJECTIVES

The shiny vestibular surfaces of teeth make it difficult to match digital dental casts to 3D stereophotogrammetric images of patient teeth. This study tested whether reducing this shininess by coating the teeth with titanium-oxide powder might improve the accuracy of the matching procedure.

METHODS

Twenty patients participated in the study. For each patient, 3D stereophotogrammetric images were taken without and with a powder coating. Separately, digital dental casts were created. Next, the digital dental casts were fused with the 3D stereophotogrammetric images of either non-powdered or powdered dentition. Distance maps were created to evaluate the inter-surface distance between the digital dental cast and the 3D images. The matching accuracy was compared for dentition with and without powdering.

RESULTS

Of all recorded distances between corresponding points, 95% was smaller than 0.84mm for the powdered dentition and smaller than 0.90mm for the non-powdered dentition. Although powdered dentition showed significantly better matching than non-powdered dentition, the difference was less than 0.1mm. Intra-observer statistics showed that five out of 24 repetitions gave significantly different results, but only for dentition that was not powdered.

LIMITATIONS

The patients did not have any major malocclusions. Severe malocclusions might cause greater difficulty in matching the dentition without powder. Only one type of powder was used, but it effectively reduced shininess.

CONCLUSION

Powdering the dentition had a small, but significant, positive effect on matching. However, this effect was of minor clinical importance. Therefore, we do not recommend powdering the dentition for 3D stereophotogrammetric images used for matching procedures.

The 3D Facial Norms Database: Part 1. A Web-Based Craniofacial Anthropometric and Image Repository for the Clinical and Research Community

With the current widespread use of three-dimensional (3D) facial surface imaging in clinical and research environments, there is a growing demand for high-quality craniofacial norms based on 3D imaging technology. The principal goal of the 3D Facial Norms (3DFN) project was to create an interactive, Web-based repository of 3D facial images and measurements. Unlike other repositories, users can gain access to both summary-level statistics and individual-level data, including 3D facial landmark coordinates, 3D-derived anthropometric measurements, 3D facial surface images, and genotypes from every individual in the dataset. The 3DFN database currently consists of 2454 male and female participants ranging in age from 3 to 40 years. The subjects were recruited at four US sites and screened for a history of craniofacial conditions. The goal of this article is to introduce readers to the 3DFN repository by providing a general overview of the project, explaining the rationale behind the creation of the database, and describing the methods used to collect the data. Sex- and age-specific summary statistics (means and standard deviations) and growth curves for every anthropometric measurement in the 3DFN dataset are provided as a supplement available online. These summary statistics and growth curves can aid clinicians in the assessment of craniofacial dysmorphology.

3D stereophotogrammetry facial analysis of Angle I subjects: gender comparison

Objective The aim of this study was to establish reference parameters for facial analysis in subjects with Angle’s Class I occlusion by means of stereophotogrammetry, comparing men and women. Material and method Twenty-six healthy young adults with Angle’s Class I occlusion volunteered to participate in the study, 15 males and 11 females, ages between 18 and 30 years old (22 years ± 5). These subjects were clinically examined to verify their type of occlusion. Twenty-five landmarks were performed in soft tissue, and those subjects underwent image capturing by the stereophotogrammetry technique, using the apparatus Vectra (M3-Canfield®). The following variables were measured in those images: naso-labial angle (C-Sn-Ls); (N-Prn-Pg); (N-Sn-Pg); mentolabial (Li-Ps-Pg); growth angle (T-Go-Pg), cheek area (T, Zy, Chk, Ch, Gn, Go), hemifaces' areas (T, Zy, Ft, Tr, N, Prn, C, Sn, Ls, Sto, Li Ps, Gn, Go), lip area, bilaterally (Ls, Cph, Ch, Li, Sto), and linear measurements of the lips and jaw. Result and conclusion The data were compared between genders (Student's t-test), and no statistically significant differences between groups (p>0.05) were found. Despite the limitations of this study, it is possible to conclude that, as there were no differences between men and women for the studied variables (angular, linear, and area), the data of the total sample (Class I) should be used as reference parameters in future studies. Additionally, the 3D stereophotogrammetry technique has proven to be a new possibility for facial analysis, which might be employed in several areas of dentistry.

A 3D analysis of Caucasian and African American facial morphologies in a US population

INTRODUCTION

This study aimed to compare facial morphologies of an adult African-American population to an adult Caucasian-American population using three-dimensional (3D) surface imaging.

MATERIALS AND METHODS

The images were captured using a stereophotogrammetric system (3dMDface(TM) system). Subjects were aged 19-30 years, with normal body mass index and no gross craniofacial anomalies. Images were aligned and combined using RF6 Plus Pack 2 software to produce a male and female facial average for each population. The averages were superimposed and the differences were assessed.

RESULTS

The most distinct differences were in the forehead, alar base and perioricular regions. The average difference between African-American and Caucasian-American females was 1·18±0·98 mm. The African-American females had a broader face, wider alar base and more protrusive lips. The Caucasian-American females had a more prominent chin, malar region and lower forehead. The average difference between African-American and Caucasian-American males was 1·11±1·04 mm. The African-American males had a more prominent upper forehead and periocular region, wider alar base and more protrusive lips. No notable difference occurred between chin points of the two male populations.

CONCLUSIONS

Average faces were created from 3D photographs, and the facial morphological differences between populations and genders were compared. African-American males had a more prominent upper forehead and periocular region, wider alar base and more protrusive lips. Caucasian-American males showed a more prominent nasal tip and malar area. African-American females had broader face, wider alar base and more protrusive lips. Caucasian-American females showed a more prominent chin point, malar region and lower forehead.

Face shape differs in phylogenetically related populations

3D analysis of facial morphology has delineated facial phenotypes in many medical conditions and detected fine grained differences between typical and atypical patients to inform genotype-phenotype studies. Next-generation sequencing techniques have enabled extremely detailed genotype-phenotype correlative analysis. Such comparisons typically employ control groups matched for age, sex and ethnicity and the distinction between ethnic categories in genotype-phenotype studies has been widely debated. The phylogenetic tree based on genetic polymorphism studies divides the world population into nine subpopulations. Here we show statistically significant face shape differences between two European Caucasian populations of close phylogenetic and geographic proximity from the UK and The Netherlands. The average face shape differences between the Dutch and UK cohorts were visualised in dynamic morphs and signature heat maps, and quantified for their statistical significance using both conventional anthropometry and state of the art dense surface modelling techniques. Our results demonstrate significant differences between Dutch and UK face shape. Other studies have shown that genetic variants influence normal facial variation. Thus, face shape difference between populations could reflect underlying genetic difference. This should be taken into account in genotype-phenotype studies and we recommend that in those studies reference groups be established in the same population as the individuals who form the subject of the study.

Comparison of facial morphologies between adult Chinese and Houstonian Caucasian populations using three-dimensional imaging

The objective of this study was to compare the facial morphologies of an adult Chinese population to a Houstonian white population. Three-dimensional (3D) images were acquired via a commercially available stereophotogrammetric camera system, 3dMDface™. Using the system, 100 subjects from a Houstonian population and 71 subjects from a Chinese population were photographed. A complex mathematical algorithm was performed to generate a composite facial average (one for males and one for females) for each subgroup. The computer-generated facial averages were then superimposed based on a previously validated superimposition method. The facial averages were evaluated for differences. Distinct facial differences were evident between the subgroups evaluated. These areas included the nasal tip, the peri-orbital area, the malar process, the labial region, the forehead, and the chin. Overall, the mean facial difference between the Chinese and Houstonian female averages was 2.73±2.20mm, while the difference between the Chinese and Houstonian males was 2.83±2.20mm. The percent similarity for the female population pairings and male population pairings were 10.45% and 12.13%, respectively. The average adult Chinese and Houstonian faces possess distinct differences. Different populations and ethnicities have different facial features and averages that should be considered in the planning of treatment.

3D comparison of average faces in subjects with oral clefts

This prospective cross-sectional, case-controlled morphometric study assessed three dimensional (3D) facial morphological differences between average faces of 103 children aged 8-12 years; 40 with unilateral cleft lip and palate (UCLP), 23 with unilateral cleft lip and alveolus (UCLA), 19 with bilateral cleft lip and palate (BCLP), 21 with isolated cleft palate (ICP), and 80 gender and age-matched controls. 3D stereophotogrammetric facial scans were recorded for each participant at rest. Thirty-nine landmarks were digitized for each scan, and x-, y-, z-coordinates for each landmark were extracted. A 3D photorealistic average face was constructed for each participating group and subjective and objective comparisons were carried out between each cleft and control average faces. Marked differences were observed between all groups. The most severely affected were groups where the lip and palate were affected and repaired (UCLP and UCLA). The group with midsagittal palatal deformity and repair (ICP) was the most similar to the control group. The results revealed that 3D shape analysis allows morphometric discrimination between subjects with craniofacial anomalies and the control group, and underlines the potential value of statistical shape analysis in assessing the outcomes of cleft lip and palate surgery, and orthodontic treatment.

Three-dimensional evaluation of changes in lip position from before to after orthodontic appliance removal

INTRODUCTION

Our objectives were to develop a reproducible method of superimposing 3-dimensional images for measuring soft-tissue changes over time and to use this method to document changes in lip position after the removal of orthodontic appliances.

METHODS

Three-dimensional photographs of 50 subjects were made in repose and maximum intercuspation before and after orthodontic appliance removal with a stereo camera. For reliability assessment, 2 photographs were repeated for 15 patients. The images were registered on stable areas, and surface-to-surface measurements were made for defined landmarks.

RESULTS

Mean changes were below the level of clinical significance (set at 1.5 mm). However, 51% and 18% of the subjects experienced changes greater than 1.5 mm at the commissures and lower lips, respectively.

CONCLUSIONS

The use of serial 3-dimensional photographs is a reliable method of documenting soft-tissue changes. Soft-tissue changes after appliance removal are not clinically significant; however, there is great individual variability.

Creation of the virtual patient for the study of facial morphology

The author provides an overview of the new imaging technologies that allow the practitioner to accurately capture the patient's soft tissue facial morphology and underlying bones and teeth, including details of dental model integration. This article describes how a virtual patient is created and manipulated and the practical use of this technology. It takes the quantification of the 3D surface further by proposing a reference framework of landmarks of craniofacial structure that can be used for comparison of surgical change, growth, gender, and phenotype.

Measuring progressive soft tissue change with nasoalveolar molding using a three-dimensional system

BACKGROUND

For craniofacial orthodontics and surgery to progress, accurate temporal evaluation of soft tissue and skeletal change with treatment is necessary. Evolution in three-dimensional imaging eliminates certain inherent challenges in making such measurements in infants with facial clefts.

OBJECTIVE

The aim of this pilot study was to measure progressive three-dimensional changes in nasal form in a series of infants with facial clefts during the course of presurgical nasoalveolar molding.

MATERIALS AND METHODS

In 5 infants with unrepaired cleft lip and palate, three-dimensional photographs were obtained using the 3dMD system (3dMD, Inc, Atlanta, GA) at 2-week intervals during nasoalveolar molding treatment. Using the 3dMD Vultus software, temporal soft tissue changes were evaluated quantitatively based on three-dimensional linear measurements of 3 landmarks in the nasal area and qualitative changes in the surface shell.

RESULTS

Increase in columellar length on the cleft side and decrease of the nostril floor on the noncleft side were observed in all subjects. Progressive changes were observed most significantly in week 4 (T3) into treatment.

CONCLUSIONS

This pilot study describes an approach using the 3dMD photo system with Vultus software for measuring the progressive change in the nasal soft tissues. The 3dMD system was believed to be valuable for facial analysis in this setting.

Three-dimensional gender differences in facial form of children in the North East of England

The aim of the prospective cross-sectional morphometric study was to explore three dimensional (3D) facial shape and form (shape plus size) variation within and between 8- and 12-year-old Caucasian children; 39 males age-matched with 41 females. The 3D images were captured using a stereophotogrammeteric system, and facial form was recorded by digitizing 39 anthropometric landmarks for each scan. The x, y, z coordinates of each landmark were extracted and used to calculate linear and angular measurements. 3D landmark asymmetry was quantified using Generalized Procrustes Analysis (GPA) and an average face was constructed for each gender. The average faces were superimposed and differences were visualized and quantified. Shape variations were explored using GPA and PrincipalComponent Analysis. Analysis of covariance and Pearson correlation coefficients were used to explore gender differences and to determine any correlation between facial measurements and height or weight. Multivariate analysis was used to ascertain differences in facial measurements or 3D landmark asymmetry. There were no differences in height or weight between genders. There was a significant positive correlation between facial measurements and height and weight and statistically significant differences in linear facial width measurements between genders. These differences were related to the larger size of males rather than differences in shape. There were no age- or gender-linked significant differences in 3D landmark asymmetry. Shape analysis confirmed similarities between both males and females for facial shape and form in 8- to 12-year-old children. Any differences found were related to differences in facial size rather than shape.

Facial Movement in 3 Dimensions

Objective. To construct 3-dimensional (3D) templates of average lip movement based on a group of normal healthy subjects.

Study Design. Cross-sectional study.

Setting. School of Dentistry, Cardiff University, United Kingdom.

Subjects and Methods. One hundred fifteen white subjects were asked to perform 2 reproducible verbal gestures (/puppy/ and /rope/) in a normal relaxed manner. The sequences were captured using a noninvasive, 3D motion scanner (3dMDFace Dynamic System). Mesh-registration software was used to align sequential facial shells to a standardized reference plane. Lip movement during the verbal facial gestures was quantified using the displacement vectors ( x, y, z coordinates) of 6 lip landmarks of sequential 3D facial shells subtracted from the reference or rest shell. Descriptive statistics were used to build references for average lip movement, and independent t tests were used to compare lip movement between men and women.

Results. Mean reference movements were created for lip opening, lip stretch, and lip purse that corresponded to the visemes /pu/ /ppy/ and /rope/, respectively. There were statistically significant differences in the lip movement between genders for the visemes /pu/ and /ppy/, although when quantified these were found not to be of clinical significance. Men favored left-sided movement and women right-sided movement, although only slightly—again, when quantified, this was considered to be within symmetrical limits.

Conclusion. It was possible to quantify and create normal templates of lip movement for the words /puppy/ and /rope/. Men and women show similar standardized lip movements for these 2 words.