Photographic Facial Soft Tissue Analysis by Means of Linear and Angular Measurements in an Adolescent Persian Population

A Validity Analysis of Text-to-Image Generative Artificial Intelligence Models for Craniofacial Anatomy Illustration

Background: Anatomically accurate illustrations are imperative in medical education, serving as crucial tools to facilitate comprehension of complex anatomical structures. While traditional illustration methods involving human artists remain the gold standard, the rapid advancement of Generative Artificial Intelligence (GAI) models presents a new opportunity to automate and accelerate this process. This study evaluated the potential of GAI models to produce craniofacial anatomy illustrations for educational purposes. Methods: Four GAI models, including Midjourney v6.0, DALL-E 3, Gemini Ultra 1.0, and Stable Diffusion 2.0 were used to generate 736 images across multiple views of surface anatomy, bones, muscles, blood vessels, and nerves of the cranium in both oil painting and realistic photograph styles. Four reviewers evaluated the images for anatomical detail, aesthetic quality, usability, and cost-effectiveness. Inter-rater reliability analysis assessed evaluation consistency. Results: Midjourney v6.0 scored highest for aesthetic quality and cost-effectiveness, and DALL-E 3 performed best for anatomical detail and usability. The inter-rater reliability analysis demonstrated a high level of agreement among reviewers (ICC = 0.858, 95% CI). However, all models showed significant flaws in depicting crucial anatomical details such as foramina, suture lines, muscular origins/insertions, and neurovascular structures. These limitations were further characterized by abstract depictions, mixing of layers, shadowing, abnormal muscle arrangements, and labeling errors. Conclusions: These findings highlight GAI's potential for rapidly creating craniofacial anatomy illustrations but also its current limitations due to inadequate training data and incomplete understanding of complex anatomy. Refining these models through precise training data and expert feedback is vital. Ethical considerations, such as potential biases, copyright challenges, and the risks of propagating inaccurate information, must also be carefully navigated. Further refinement of GAI models and ethical safeguards are essential for safe use.

Smartphone-generated 3D facial images: reliable for routine assessment of the oronasal region of patients with cleft or mere convenience? A validation study

OBJECTIVES

To evaluate the validity and reliability of smartphone-generated three-dimensional (3D) facial images for routine evaluation of the oronasal region of patients with cleft by comparing their accuracy to that of direct anthropometry (DA) and 3dMD.

MATERIALS AND METHODS

Eighteen soft-tissue facial landmarks were manually labelled on each of the 17 (9 males and 8 females; mean age 23.3 ± 5.4 years) cleft lip and palate (CLP) patients' faces. Two surface imaging systems, 3dMDface and Bellus3D FaceApp, were used to perform two imaging operations on each labelled face. Subsequently, 32 inter-landmark facial measurements were directly measured on the labelled faces and digitally measured on the 3D facial images. Statistical comparisons were made between smartphone-generated 3D facial images (SGI), DA, and 3dMD measurements.

RESULTS

The SGI measurements were slightly higher than those from DA and 3dMD, but the mean differences between inter-landmark measurements were not statistically significant across all three methods. In terms of clinical acceptability, 16% and 59% of measures showed differences of ≤ 3 mm or ≤ 5º, with good agreement between DA and SGI and 3dMD and SGI, respectively. A small systematic bias of ± 0.2 mm was observed generally among the three methods. Additionally, the mean absolute difference between the DA and SGI methods was the highest for linear measurements (1.31 ± 0.34 mm) and angular measurements (4.11 ± 0.76º).

CONCLUSIONS

SGI displayed fair trueness compared to DA and 3dMD. It exhibited high accuracy in the orolabial area and specific central and flat areas within the oronasal region. Notwithstanding this, it has limited clinical applicability for assessing the entire oronasal region of patients with CLP. From a clinical application perspective, SGI should accurately encompass the entire oronasal region for optimal clinical use.

CLINICAL RELEVANCE

SGI can be considered for macroscopic oronasal analysis or for patient education where accuracy within 3 mm and 5º may not be critical.

Robin Sequence Facial Profile After Conservative Treatment: A Long-Term Follow-Up

INTRODUCTION

Robin sequence (RS) is a congenital clinical condition characterized by micrognathia, glossoptosis, and respiratory distress. Conservative methods could be responsible for releasing feeding and respiratory impairment but little information about mandibular growth is known in long-term follow-up.

OBJECTIVE

Assessing the longitudinal behavior of the facial profile of individuals with isolated RS who underwent conservative micrognathia treatment using photographs during the whole craniofacial growth.

METHODS

Photographs of the right facial profile of 100 patients were used (50 individuals with isolated RS and 50 individuals without craniofacial anomaly). The individuals with RS were evaluated at 3 different times (T1: infant, T2: mixed dentition, T3: permanent dentition) by measuring the facial convexity angle (FCA; G.Sn.Pog´). A comparison between T3 and control group (C), individuals without craniofacial anomalies and in permanent dentition, was also performed, checking the FCA, nasolabial angle (Ls.Sn.Cm), mentolabial fold (Li.Si.Pog´), facial inferior third (Sn.Gn´.C) angles and the ratio between middle anterior facial height and lower anterior facial height.

RESULTS

The T3 group showed an increased angle of facial convexity and increased facial inferior third angle and middle anterior facial height/lower anterior facial height ratio compared with the control group. In the longitudinal evaluation of individuals with isolated RS, significant differences were identified between T1 and T2 groups and T1 and T3 groups showing that the increased facial convexity was higher in the infants and that did not change significantly between the phases of mixed and permanent dentition.

CONCLUSIONS

RS showed increased facial convexity in all phases evaluated, but their convexity decreased with growth. When compared with individuals without craniofacial anomalies, the individuals continue to exhibit retrognathism in the permanent dentition. The lack of a mandible projection has led to a considerable number of orthognathic surgeries for the correction of discrepancies.

Can smartphones be used for routine dental clinical application? A validation study for using smartphone-generated 3D facial images

OBJECTIVES

To compare the accuracy of smartphone-generated three-dimensional (3D) facial images to that of direct anthropometry (DA) and 3dMD with the aim of assessing the validity and reliability of smartphone-generated 3D facial images for routine clinical applications.

MATERIALS AND METHODS

Twenty-five anthropometric soft-tissue facial landmarks were labelled manually on 22 orthognathic surgery patients (11 males and 11 females; mean age 26.2 ± 5.3 years). For each labelled face, two imaging operations were performed using two different surface imaging systems: 3dMDface and Bellus3D FaceApp. Next, 42 inter-landmark facial measurements amongst the identified facial landmarks were measured directly on each labelled face and also digitally on 3D facial images. The measurements obtained from smartphone-generated 3D facial images (SGI) were statistically compared with those from DA and 3dMD.

RESULTS

SGI had slightly higher measurement values than DA and 3dMD, but there was no statistically significant difference between the mean values of inter-landmark measures across the three methods. Clinically acceptable differences (≤3 mm or ≤5°) were observed for 67 % and 74 % of measurements with good agreement between DA and SGI, and 3dMD and SGI, respectively. An overall small systematic bias of ± 0.2 mm was observed between the three methods. Furthermore, the mean absolute difference between DA and SGI methods was highest for linear (1.41 ± 0.33 mm) as well as angular measurements (3.07 ± 0.73°).

CONCLUSIONS

SGI demonstrated fair trueness compared to DA and 3dMD. The central region and flat areas of the face in SGI are more accurate. Despite this, SGI have limited clinical application, and the panfacial accuracy of the SGI would be more desirable from a clinical application standpoint.

CLINICAL SIGNIFICANCE

The usage of SGI in clinical practice for region-specific macro-proportional facial assessment involving central and flat regions of the face or for patient education purposes, which does not require accuracy within 3 mm and 5° can be considered.

A deep learning framework to scale linear facial measurements to actual size using horizontal visible iris diameter: a study on an Iranian population

Digital images allow for the objective evaluation of facial appearance and abnormalities as well as treatment outcomes and stability. With the advancement of technology, manual clinical measurements can be replaced with fully automatic photographic assessments. However, obtaining millimetric measurements on photographs does not provide clinicians with their actual value due to different image magnification ratios. A deep learning tool was developed to estimate linear measurements on images with unknown magnification using the iris diameter. A framework was designed to segment the eyes' iris and calculate the horizontal visible iris diameter (HVID) in pixels. A constant value of 12.2 mm was assigned as the HVID value in all the photographs. A vertical and a horizontal distance were measured in pixels on photographs of 94 subjects and were estimated in millimeters by calculating the magnification ratio using HVID. Manual measurement of the distances was conducted on the subjects and the actual and estimated amounts were compared using Bland-Altman analysis. The obtained error was calculated as mean absolute percentage error (MAPE) of 2.9% and 4.3% in horizontal and vertical measurements. Our study shows that due to the consistent size and narrow range of HVID values, the iris diameter can be used as a reliable scale to calibrate the magnification of the images to obtain precise measurements in further research.

Relationship of psychosociocultural factors with dental malocclusion and facial appearance

Objectives:

The purpose of this study was to evaluate the relationship between psychosociocultural factors and dental malocclusion, facial appearance, and body perception.

Material and Methods:

The study was carried out with the participation of 112 female and 113 male individuals between the ages of 18 and 25. Individuals were asked to answer the Rosenberg Self-Esteem Scale, Physical Appearance Comparison Scale Revised, and Sociocultural Attitudes Towards Appearance Questionnaire 4-Revised questionnaires. Individuals were divided into three groups Class I, Class II, and Class III according to dental molar relationships. Standard facial and profile photographs of individuals in all groups were taken and soft-tissue measurements were performed.

Results:

There was no significant psychosociocultural difference between male and female individuals. However, individuals with Class III dental malocclusion compare their physical appearance more than other malocclusion groups and more experience body dissatisfaction (P > 0.05). Individuals with Class III dental malocclusion have higher lower face height, lower lip height, mentolabial angle, facial convexity angle, total facial convexity angle values, and lower forehead height/lower face height, nose height/lower face height ratio, and projection of the upper lip relative to the chin. Individuals with Class II dental malocclusion have lower chin height and anterior mandibular height/lower face height ratio, higher upper lip height/lower face height ratio, and upper lip height/anterior mandibular height ratio. Individuals with Class I dental malocclusion have a lower upper face height/lower face height ratio.

Conclusion:

Dental malocclusion groups have different facial soft tissue properties. Dental malocclusion and the facial appearance of individuals affect their lives in terms of psychosociocultural aspects.

Soft tissue profile changes during treatment of patients with Class II malocclusion

Introduction/Objective. The class II malocclusion results in disbalanced facial harmony, primarily noticeable in the profile and the lower facial third. Aside from skeletal evaluation, orthodontic diagnosis and treatment planning should include facial soft tissue analysis. The aim of the study was to identify the soft tissue profile outcomes of orthodontic treatment of Class II, division 1 malocclusion patients and to determine if these changes are related with the different treatment protocol. Methods. The first group was the non-extraction group (25 patients) treated first with the Herbst appliance, and the second group was four premolars extraction group (25 patients) treated with a multibracket appliance. The patients? cephalograms and pre- and post-treatment profile photographs were used. Results. The improvement in the non-extraction group was evident in the decrease of the nasomental angle, the angle representing the projection of the upper lip to the chin, as well as the upper lip angle. In the extraction group, the nasolabial angle showed a significant increase. Soft tissue variables showed significant differences between the groups: the total facial angle or facial convexity including the nose and the angle presenting the projection of the upper lip to chin. Conclusion. The patients treated without extractions showed a significant improvement of the convex profile and favorable soft tissue changes in the lower third of the face.

[Does gender make a difference in orthodontics? A literature review]

OBJECTIVES

The objective of this literature review is to investigate whether the gender of patients and practitioners makes any difference to orthodontic treatment.

MATERIALS AND METHODS

Sixty-nine articles were selected, the vast majority of which studied patient gender.

RESULTS

Young females are the category of patients which most often apply for orthodontic treatment, probably because of their higher aesthetic demands, despite their objective needs being no greater. Aesthetic, skeletal and dental analyses reveal an obvious dimorphism with larger dimensions in males, especially for the nose, cheekbones, mouth and mandibular canines. Nevertheless, cephalometric angular values do not vary significantly between male and female individuals. Growth is quantitatively greater in males. It also occurs later, as does eruption and maturation of their teeth. Response to the different orthodontic / orthopedic therapies would appear not to differ according to the sex of the patient.

DISCUSSION

These results, however, need to be qualified according to the country concerned, the patients' life style and mind frames, as these can modify or influence the studied parameters.

Angular Photogrammetric Soft Tissue Facial Profile Analysis of Bangladeshi Young Adults

Introduction

Angular photogrammetric soft tissue facial profile analysis provides a permanent record for the actual appearance of a person, which would also serve to establish an ideal esthetic treatment goal. The aim of the present study was to evaluate the average angular variables that define the soft tissue facial profile of a Bangladeshi sample.

Materials and Methods

This cross-sectional study was carried out at Department of Orthodontics and Dentofacial Orthopedics of Dhaka Dental College and Hospital, Bangladesh, from July to December 2015. Soft tissue facial profiles of 200 participants (100 males and 100 females) between 18 and 25 years of age, with a dental Class I occlusal relationship and harmonious soft tissue profile, were selected by convenience sampling among students, doctors, and patients of Dhaka Dental College. Standardized photographs of 200 samples were taken in the natural head position. The photographic records were analyzed with the software for Windows, Microsoft Visio 2007, Standard Edition. All data were analyzed through standard methods using Statistical Package for the Statistical Package for Social Science Software (SPSS Version-20, IBM Corp, USA).

Results

The average angular measurements for nasofrontal, total facial angle, facial angle, upper lip angle, projection of lower lip to chin, and mentolabial angle were wider in females. The mean value for nose tip angle, nasolabial angle, nasomental angle, and projection of upper lip to chin angle was higher in males compared to females. Nasofrontal angle (G-N-Nd) (P = 0.000) and mentolabial angle (Li-Sm-Pg) (P = 0.001) showed statistically significant differences. The greatest variability was found for mentolabial angle.

Conclusion

The study of angular photogrammetric soft tissue facial profile analysis of Bangladeshi young adults contributes to the establishment of standardized normal values for the population. This study provides data which can be used in treatment planning by specialists such as orthodontists, prosthodontists, plastic surgeons, and maxillofacial surgeons, who have the capability to change the soft tissue facial features.

Photogrammetric Correlation of Face with Frontal Radiographs and Direct Measurements

INTRODUCTION

Photogrammetry is a science of making measurements from photographs. As cephalometric analysis till date has focused mainly on skeletal relationships, photogrammetry may provide a means to reliably assess and compare soft tissue and hard tissue measurements.

AIM

To compare and correlate linear measurements taken directly from subject's faces and from standardized frontal cephalometric radiographs and to correlate them with standardized frontal facial photographs of Indian population and to obtain mean values.

MATERIALS AND METHODS

A cross-sectional study was conducted on 30 subjects of Indian origin. Frontal cephalograms and standardized frontal photographs were obtained from subjects in the age group of 18- 25 years. Vernier calipers were used to obtain facial measurements directly. Photographs and radiographs were uploaded and measured using Nemoceph software. Analogous cephalometric, photographic and direct measurements were compared by one-way ANOVA to assess Pearson correlation coefficients for 12 linear measurements (6 vertical, 6 horizontal). Bonferroni post-hoc test was done for pair wise comparison.

RESULTS

Among all measurements used, O_R-O_L (orbitale right-orbitale left) showed a high correlation r = 0.76, 0.70, 0.71. There was moderate correlation with En_R-En_L (endocanthion rt - endocanthion lt) r² = 0.62, 0.68, 0.68. Highly significant correlation was evident with N-Sn, En_R-En_L and Ag_R-Ag_L with p<0.001.

CONCLUSION

A statistically significant correlation was found between photographic, radiographic and direct measurements. Therefore, photogrammetry has proven to be an alternative diagnostic tool that can be used in epidemiologic studies when there is a need for a simple, basic, non-invasive and cost-effective method.