Automatic soft-tissue analysis on orthodontic frontal and lateral facial photographs based on deep learning.

BACKGROUND: To establish the automatic soft-tissue analysis model based on deep learning that performs landmark detection and measurement calculations on orthodontic facial photographs to achieve a more comprehensive quantitative evaluation of soft tissues. METHODS: A total of 578 frontal photographs and 450 lateral photographs of orthodontic patients were collected to construct datasets. All images were manually annotated by two orthodontists with 43 frontal-image landmarks and 17 lateral-image landmarks. Automatic landmark detection models were established, which consisted of a high-resolution network, a feature fusion module based on depthwise separable convolution, and a prediction model based on pixel shuffle. Ten measurements for frontal images and eight measurements for lateral images were defined. Test sets were used to evaluate the model performance, respectively. The mean radial error of landmarks and measurement error were calculated and statistically analysed to evaluate their reliability. RESULTS: The mean radial error was 14.44 ± 17.20 pixels for the landmarks in the frontal images and 13.48 ± 17.12 pixels for the landmarks in the lateral images. There was no statistically significant difference between the model prediction and manual annotation measurements except for the mid facial-lower facial height index. A total of 14 measurements had a high consistency. CONCLUSION: Based on deep learning, we established automatic soft-tissue analysis models for orthodontic facial photographs that can automatically detect 43 frontal-image landmarks and 17 lateral-image landmarks while performing comprehensive soft-tissue measurements. The models can assist orthodontists in efficient and accurate quantitative soft-tissue evaluation for clinical application.

Evaluation of the soft tissue facial profile in different skeletal malocclusions in relation to age.

BACKGROUND: The aim of the study was to assess the thickness of the soft tissue facial profile (STFP) in relation to the skeletal malocclusion, age and gender. METHODS: All patients, aged 7-35 years, who were seeking orthodontic treatment at the Department of Orthodontics, Medical University of Warsaw between 2019 and 22 were included in the study. All patients had lateral head radiographs taken before the treatment. The cephalometric analysis was performed including the STFP analysis. The patients were allocated to one of six groups based on age and skeletal relations (ANB angle). The minimum number of patients in each group was 60 with equal gender distribution. The STFP analysis included ten linear measurements. RESULTS: A total of 300 patients were included in the study and allocated to five groups. Group 6 (growing patients with skeletal Class III malocclusion) was not included in the study as it failed to achieve the assumed group size. There were significant differences in the thickness of the STFP in relation to the skeletal malocclusions. Adults with skeletal Class III malocclusion had significantly thicker subnasal soft tissues compared to patients with skeletal Class I and Class II malocclusions. The thickness of the lower lip in patients with Class II skeletal malocclusion was significantly bigger compared to the other groups. Children and adolescents with Class II malocclusions had thicker lower lip in comparison to the group with Class I malocclusion. The majority of the STFP measurements were significantly smaller in children and adolescents compared to adults. The thickness of the STFP in males was significantly bigger in all age groups compared to females. CONCLUSIONS: The thickness of facial soft tissues depends on the patient's age and gender. The degree of compensation of the skeletal malocclusion in the STFP may be a decisive factor during orthodontic treatment planning regarding a surgical approach or a camouflage treatment of skeletal defects.

MATLAB-Based Algorithm and Software for Analysis of Wavy Collagen Fibers.

Knowledge of soft tissue fiber structure is necessary for accurate characterization and modeling of their mechanical response. Fiber configuration and structure informs both our understanding of healthy tissue physiology and of pathological processes resulting from diseased states. This study develops an automatic algorithm to simultaneously estimate fiber global orientation, abundance, and waviness in an investigated image. To our best knowledge, this is the first validated algorithm which can reliably separate fiber waviness from its global orientation for considerably wavy fibers. This is much needed feature for biological tissue characterization. The algorithm is based on incremental movement of local regions of interest (ROI) and analyzes two-dimensional images. Pixels belonging to the fiber are identified in the ROI, and ROI movement is determined according to local orientation of fiber within the ROI. The algorithm is validated with artificial images and ten images of porcine trachea containing wavy fibers. In each image, 80-120 fibers were tracked manually to serve as verification. The coefficient of determination R2 between curve lengths and histograms documenting the fiber waviness and global orientation were used as metrics for analysis. Verification-confirmed results were independent of image rotation and degree of fiber waviness, with curve length accuracy demonstrated to be below 1% of fiber curved length. Validation-confirmed median and interquartile range of R2, respectively, were 0.90 and 0.05 for curved length, 0.92 and 0.07 for waviness, and 0.96 and 0.04 for global orientation histograms. Software constructed from the proposed algorithm was able to track one fiber in about 1.1 s using a typical office computer. The proposed algorithm can reliably and accurately estimate fiber waviness, curve length, and global orientation simultaneously, moving beyond the limitations of prior methods.

Comparing Direct Measurements and Three-Dimensional (3D) Scans for Evaluating Facial Soft Tissue.

The inspection of patients' soft tissues and the effects of various dental procedures on their facial physiognomy are quite challenging. To minimise discomfort and simplify the process of manual measuring, we performed facial scanning and computer measurement of experimentally determined demarcation lines. Images were acquired using a low-cost 3D scanner. Two consecutive scans were obtained from 39 participants, to test the scanner repeatability. An additional ten persons were scanned before and after forward movement of the mandible (predicted treatment outcome). Sensor technology that combines red, green, and blue (RGB) data with depth information (RGBD) integration was used for merging frames into a 3D object. For proper comparison, the resulting images were registered together, which was performed with ICP (Iterative Closest Point)-based techniques. Measurements on 3D images were performed using the exact distance algorithm. One operator measured the same demarcation lines directly on participants; repeatability was tested (intra-class correlations). The results showed that the 3D face scans were reproducible with high accuracy (mean difference between repeated scans <1%); the actual measurements were repeatable to some extent (excellent only for the tragus-pogonion demarcation line); computational measurements were accurate, repeatable, and comparable to the actual measurements. Three dimensional (3D) facial scans can be used as a faster, more comfortable for patients, and more accurate technique to detect and quantify changes in facial soft tissue resulting from various dental procedures.

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.

Photogrammetric Evaluation of Soft Tissue Profile and Frontal Photographs in Repaired Bilateral Cleft Lip and Palate.

OBJECTIVE: To evaluate the soft tissue profile and frontal photographs of 8- to 12-year-old patients with repaired complete bilateral cleft lip and palate (BCLP). METHODS: The profile and frontal photographs obtained from 31 nonsyndromic BCLP children (aged 8-12 years: 14 boys and 17 girls) were analyzed and compared with an age- and sex-matched normal population (18 boys and 32 girls). In each patient, 12 soft tissue angular and proportional parameters on the frontal photograph and 12 angular parameters for the profile photographs were developed and measured. Student t test was used to compare the mean value of the parameters between both sexes. RESULTS: In the frontal view, there was a significant difference between the 2 study groups in the facial symmetry angle (P < .001), lower facial height proportion (P < .001), upper lip proportion (P < .001), and interalar width/distance between the inner canthus of the eyes (P < .001). In the profile view, there was a significant difference between the control group and the patients with cleft lip and palate in terms of nasofrontal angle (P < .001), nasal angle (P < .001), angle of the inferior facial third (P = .032), head position angle (P < .001), facial convexity angle (P < .001), total facial convexity angle (P < .001), and vertical nasal angle (P < .001). CONCLUSION: In comparison with the normal population, the face of patients with repaired BCLP showed several soft tissue deformities, especially in the nasofrontal region, even after a surgical repair.

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.

Cephalometric Soft Tissue Standard and Gender Dimorphism in Nasal Prominence estimated By Holdaway's Analysis in Patients visiting College of Dentistry, Aljouf University.

INTRODUCTION: The objectives were to see the nasal prominence norm and the gender dimorphism in nasal prominence measured by Holdaway's soft tissue analysis. MATERIALS AND METHODS: The sample size was 100 (50 males and 50 females). The subjects included in the study were of Saudi origin with class I skeletal and dental relationship and all teeth present. The age group of the patients was between 18 and 28 years. The radiographs were traced and analyzed by two students and cross-checked by an orthodontist. The nasal prominence was measured according to the technique described by Holdaway. RESULTS: The descriptive statistics were calculated for both male and female groups. The mean value of nasal prominence when male and female samples were combined was 14.08 mm. No statistically significant difference was found (p = 0.083) when genders were compared. The level of significance was set at p < 0.05. CONCLUSION: No statistically significant difference was found when genders were compared. The value for males was normal while the value for females was less than Holdaway's normal. CLINICAL SIGNIFICANCE: These values would aid in treatment planning for orthognathic surgery and orthodontic treatment.

Ethnic-Guided Soft Tissue Cephalometric Analysis on Lambani Indian Inhabitants for Forensic Facial Reconstruction.

BACKGROUND: Forensic craniofacial reconstruction is a combination of both scientific technique and artistic skill that assist facial soft tissue approximation on the skull to obtain an image of an individual that varies in the different ethnic groups depending on genetic and environmental factors such as soft tissue norms. OBJECTIVES: The present study was aimed to evaluate the soft tissue norms for Lambani Indian tribes spread across the state of Karnataka in India and compare them with the local inherent ethnolinguistic Kannadiga population. MATERIAL AND METHODS: Forty healthy individuals encompassing 20 Lambanis and 20 Kannadigas were selected using demographic information. Lateral cephalograms obtained were analyzed for various soft tissue landmarks that include facial angle, upper lip curvature, skeletal convexity, H angle, nose tip to H-line, upper sulcus depth, lower sulcus depth, upper lip thickness, upper lip strain, lower lip to H line, soft tissue chin thickness, and glabella. RESULTS: It was observed that glabella thickness, upper sulcus depth, and lower lip to H line showed a significant difference between Lambani and Kannadiga populations. Lambani's have a higher facial angle than the Kannadiga group though not statistically significant. Gender-wise comparison had shown a significant difference in variables on upper sulcus depth, glabella among females, and lower lip to H line, glabella among males. CONCLUSION: The differences obtained between the two ethnic groups in this study clearly suggest the need for separate soft tissue thickness norms for distinctive populations that could be vital in the facial reconstruction of an individual in the field of forensic investigation to narrow down the identification process.

Nasolabial soft tissue effects of segmented and non-segmented Le Fort I osteotomy using a modified alar cinch technique-a cone beam computed tomography evaluation.

The aim of this study was to verify soft tissues changes and the effect of a minimally invasive surgical technique in the nasolabial region after segmented and non-segmented Le Fort I osteotomy, using cone beam computed tomography (CBCT) evaluation of three-dimensional (3D) volume surfaces. Two groups were evaluated: group 1, bimaxillary surgery with maxillary segmentation (n=40); group 2, bimaxillary surgery without maxillary segmentation (n=40). In both groups, a specific alar cinching technique was used to control nasal base broadening. CBCT evaluation was performed at three different treatment time points: T0, 1 month before surgery; T1, 1 month after surgery; T2, 1year after surgery. The results showed statistically significant differences in the nasolabial area (P<0.001). For group 1, the mean change in alar base width (Alinf-Alinf) was 1.31±1.40mm at T1 and 0.93±1.77mm at T2; for group 2 these values were 1.12±2.01mm at T1 and 0.54±1.54mm at T2. For group 1, the mean changes in inter-alar width (Al-Al) were 1.68±1.46mm at T1 and 1.49±1.33mm at T2; for group 2, they were 2.22±1.93mm at T1 and 1.34±1.79mm at T2. The alar cinch technique proposed here appears to be effective in controlling nasolabial soft tissue widening.

Clinical and Radiological Evaluation of Delayed and Early Loading of Single-Tooth Implant Placement: A 6-Month, Prospective, Randomized, Follow-up Clinical Study.

PURPOSE: The purpose of the study was to compare delayed and early loaded single-tooth implant technique. MATERIALS AND METHODS: A randomized, prospective clinical trial was conducted to evaluate the clinical and radiological parameters of delayed and early loading of single-tooth implant placement. Fourteen male or female patients were selected randomly, who had single tooth missing in mandibular posterior region. A delayed implant placement technique was followed in these regions. A Hi-Tech implant (Life Care Implants) was performed. The patients were divided into two groups: delayed loading group and early loading group. In delayed loading groups, implants were loaded after 3 months, and in early loading groups, implants were loaded within 7 days to 2 months. Soft tissue and radiological bone loss were assessed at baseline, 3 months, and 6 months. The parameters assessed were plaque index, gingival index, probing pocket depth, thickness of peri-implant mucosa, and bone loss (radiographically). RESULTS: The results show that there was no statistical difference in indexes taken between delayed loading and early loading groups. CONCLUSION: In this study, after first 6 months there was no difference in success rate between delayed loading or early loading of implants. This study also showed that more bone loss occurred around delayed loading implants. So it can be concluded that early loading technique can be successfully practiced instead of delayed loading of implants.

Three-dimensional analysis of nasolabial soft tissue changes after Le Fort I osteotomy: a systematic review of the literature.

A systematic review was conducted to investigate the three-dimensional (3D) effect of Le Fort I osteotomy on the nasolabial soft tissues. The literature search was conducted using the MEDLINE (accessed via PubMed), Embase, and Cochrane electronic databases until January 2018. A total of 333 studies were identified (PubMed, n=292; Embase, n=41; Cochrane Library, n=0). Seventeen met the inclusion criteria. The studies were essentially retrospective. The risk of bias was considered high in 15 studies, medium in one study, and low in one study. 3D soft tissue analysis was performed at least 6months after surgery (mean 8.3months). The main image acquisition technique reported was cone beam computed tomography (CBCT), associated or not with 3D photography. Approximately 50% of the studies performed two-jaw surgery, 25% performed maxillary surgery only, and the other 25% included heterogeneous intervention groups. The most reported nasolabial changes were anterior and lateral movements of the nasomaxillary soft tissues and upper lip, together with anterior and superior movement of the nasal tip. The alar cinch suture and V-Y closure technique seemed to have little effect in counteracting the undesirable postoperative nasolabial changes. CBCT superimposition presented a reliable 3D assessment for simultaneous measurement of skeletal and soft tissue changes.

Angular photogrammetric analysis of the soft-tissue facial profile of Indian adults.

INTRODUCTION:: Soft-tissue analysis has become an important component of orthodontic diagnosis and treatment planning. Photographic evaluation of an orthodontic patient is a very close representation of the appearance of the person. The previously established norms for soft-tissue analysis will vary for different ethnic groups. Thus, there is a need to develop soft-tissue facial profile norms pertaining to Indian ethnic groups. AIM AND OBJECTIVES:: The aim of this study is to establish the angular photogrammetric standards of soft-tissue facial profile for Indian males and females and also to compare sexual dimorphism present between them. MATERIALS AND METHODS: The lateral profile photographs of 300 random participants (150 males and 150 females) between ages 18 and 25 years were taken and analyzed using FACAD tracing software. Inclusion criteria were angles Class I molar occlusion with acceptable crowding and proclination, normal growth and development with well-aligned dental arches, and full complements of permanent teeth irrespective of third molar status. This study was conducted in Indian population, and samples were taken from various cities across India. Descriptive statistical analysis was carried out, and sexual dimorphism was evaluated by Student's t-test between males and females. RESULTS: The results of the present study showed statistically significant (P < 0.05) gender difference in 5 parameters out of 12 parameters in Indian population. CONCLUSION: In the present study, soft-tissue facial measurements were established by means of photogrammetric analysis to facilitate orthodontists to carry out more quantitative evaluation and make disciplined decisions. The mean values obtained can be used for comparison with records of participants with the same characteristics by following this photogrammetric technique.

Comparison of 3D Scanning Versus 2D Photography for the Identification of Facial Soft-Tissue Landmarks.

BACKGROUND: Three dimensional facial scanning is an innovation that provides opportunity for digital data acquisition, smile analysis and communication of treatment plan and outcome with patients. OBJECTIVES: To assess the applicability of 3D facial scanning as compared to 2D clinical photography. MATERIALS & METHODS: Sample consisted of thirty Caucasians aged between 25 and 50 years old, without any dentofacial deformities. Fifteen soft-tissue facial landmarks were identified twice by 3 observers on 2D and 3D images of the 30 subjects. Five linear proportions and nine angular measurements were established in the orbital, nasal and oral regions. These data were compared to anthropometric norms of young Caucasians. Furthermore, a questionnaire was completed by 14 other observers, according to their personal judgment of the 2D and 3D images. RESULTS: Quantitatively, proportions linking the three facial regions in 3D were closer to the clinical standard (for 2D 3.3% and for 3D 1.8% error rate). Qualitatively, in 67% of the cases, observers were as confident about 3D as they were about 2D. Intra-observer Correlation Coefficient (ICC) revealed a better agreement between observers in 3D for the questions related to facial form, lip step and chin posture. CONCLUSION: The laser facial scanning could be a useful and reliable tool to analyze the circumoral region for orthodontic and orthognathic treatments as well as for plastic surgery planning and outcome.

Assessment of facial soft-tissue profiles based on lateral photographs versus three-dimensional face scans.

OBJECTIVES: The purpose of this study was to compare two-dimensional (2D) lateral photographs versus three-dimensional (3D) face scans in analyzing facial profiles using Schwarz's concept of the jaw profile field (JPF) in its original 2D and in a modified 3D version. In addition, the distribution of the facial profile types described by Schwarz were examined. MATERIALS AND METHODS: Of 75 adult volunteers recruited specifically for this study, we obtained both photographs (Nikon D 300S; Nikon, Düsseldorf, Germany) and scans (FaceSCAN3D Scientific Photolab 60 Hz; 3D-Shape, Erlangen, Germany) in a standardized setting. Four raters analyzed the pertinent measurements using image analysis software (Onyx Ceph 3; Image Instruments, Chemnitz, Germany). Statistical analysis was conducted using the R suite environment (v. 3.2.1; R Foundation for Statistical Computing, Vienna, Austria). RESULTS: Intraobserver reliability was substantial for two raters (κ = 0.61-0.8), moderate for one (κ = 0.41-0.60), and almost perfect for one (κ = 0.81-1.00). As for interobserver reliability, we observed moderate agreement between the two basic technologies tested, but internal agreement was only moderate even within the 2D view modes (average κ = 0.51) versus almost perfect within the 3D view modes (κ = 0.84-0.94). Forward-slanting anteface was clearly the most common (43.27%) and straight retroface the least common (0.3%) diagnosis. Only a minority of patients (18.38% of women and 16.15% of men) had straight as opposed to slanting profiles. CONCLUSIONS: Given our findings of acceptable agreement between 3D scanning and 2D lateral photography, in combination with almost perfect internal agreement between different 3D view modes, it appears useful to adapt Schwarz's method of facial profile assessment for clinical use in 3D virtual environments.

Three-dimensional assessment of facial asymmetry: A systematic review.

For patients with facial asymmetry, complete and precise diagnosis, and surgical treatments to correct the underlying cause of the asymmetry are significant. Conventional diagnostic radiographs (submento-vertex projections, posteroanterior radiography) have limitations in asymmetry diagnosis due to two-dimensional assessments of three-dimensional (3D) images. The advent of 3D images has greatly reduced the magnification and projection errors that are common in conventional radiographs making it as a precise diagnostic aid for assessment of facial asymmetry. Thus, this article attempts to review the newly introduced 3D tools in the diagnosis of more complex facial asymmetries.

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

OBJECTIVE: To obtain objective average measurements of the profile and frontal facial soft tissue to be used as a guide for aesthetic treatment goals. Methods and Materials : This observational study included 110 females and 130 males high school students aged 16-18 years. None of the subjects had any facial deformities. All of them and their parents gave consent to take part in this study. In each case, two standard photographs of profile and frontal views were taken 27 landmarks were digitized on photographs. The mean, standard deviation, and range for a total of 43 facial indices were calculated digitally by computer software. The Student's t-test was used to compare males and females. Results : The ratio between the lower and middle facial thirds was one to one, but the height of the upper facial third was proportionally smaller than the other two-thirds in both sexes. Boys had greater nasal length, depth, and prominence than girls with statistically significant differences. Both upper and lower lips were more prominent in girls than in boys. All measurements of the chin showed sexual dimorphism characterized by greater chin height and prominence and deeper mentolabial sulcus. Boys had greater facial dimensions than girls. Mouth width, nasal base width, and intercanthal distance were significantly greater in boys. Conclusion : The labial, nasal, and chin areas showed sexual dimorphism in most of the parameters used in this study. Boys had larger faces, greater facial heights, longer nasal, labial, and chin lengths, and greater nasal, labial, and chin prominence.

Biomechanical study on the bladder neck and urethral positions: simulation of impairment of the pelvic ligaments.

Excessive mobility of the bladder neck and urethra are common features in stress urinary incontinence. We aimed at assessing, through computational modelling, the bladder neck position taking into account progressive impairment of the pelvic ligaments. Magnetic resonance images of a young healthy female were used to build a computational model of the pelvic cavity. Appropriate material properties and constitutive models were defined. The impairment of the ligaments was simulated by mimicking a reduction in their stiffness. For healthy ligaments, valsalva maneuver led to an increase in the α angle (between the bladder neck-symphysis pubis and the main of the symphysis) from 91.8° (at rest) to 105.7°, and 5.7 mm of bladder neck dislocation, which was similar to dynamic imaging of the same woman (α angle from 80° to 103.3°, and 5mm of bladder neck movement). For 95% impairment, they enlarged to 124.28° and 12 mm. Impairment to the pubourethral ligaments had higher effect than that of vaginal support (115° vs. 108°, and 9.1 vs. 7.3mm). Numerical simulation could predict urethral motion during valsalva maneuver, for both healthy and impaired ligaments. Results were similar to those of continent women and women with stress urinary incontinence published in the literature. Biomechanical analysis of the pubourethral ligaments complements the biomechanical study of the pelvic cavity in urinary incontinence. It may be useful in young women presenting stress urinary incontinence without imaging evidence of urethral and muscle lesions or organ descend during valsalva, and for whom fascial damage are not expected.

Three-dimensional evaluation of the relationship between jaw divergence and facial soft tissue dimensions.

OBJECTIVE: To evaluate the relationship between mandibular divergence and vertical and transverse dimensions of the face. MATERIALS AND METHODS: A sample was recruited from the orthodontic clinic of the University of Otago, New Zealand. The recruited participants (N  =  60) were assigned to three different groups based on the mandibular plane angle (hyperdivergent, n  =  20; normodivergent, n  =  20; and hypodivergent, n  =  20). The sample consisted of 31 females and 29 males, with a mean age of 21.1 years (SD ± 5.0). Facial scans were recorded for each participant using a three-dimensional (3D) white-light scanner and then merged to form a single 3D image of the face. Vertical and transverse measurements of the face were assessed from the 3D facial image. RESULTS: The hyperdivergent sample had a significantly larger total and lower anterior facial height than the other two groups (P < .05), although no difference was found for the middle facial height (P > .05). Similarly, there were no significant differences in the transverse measurements of the three study groups (P > .05). Both gender and body mass index (BMI) had a greater influence on the transverse dimension. CONCLUSIONS: Hyperdivergent facial types are associated with a long face but not necessarily a narrow face. Variations in facial soft tissue vertical and transversal dimensions are more likely to be due to gender. Body mass index has a role in mandibular width (GoGo) assessment.

A comparison study of different facial soft tissue analysis methods.

OBJECTIVES: The purpose of this study was to evaluate several different facial soft tissue measurement methods. MATERIALS AND METHODS: After marking 15 landmarks in the facial area of 12 mannequin heads of different sizes and shapes, facial soft tissue measurements were performed by the following 5 methods: Direct anthropometry, Digitizer, 3D CT, 3D scanner, and DI3D system. With these measurement methods, 10 measurement values representing the facial width, height, and depth were determined twice with a one week interval by one examiner. These data were analyzed with the SPSS program. RESULTS: The position created based on multi-dimensional scaling showed that direct anthropometry, 3D CT, digitizer, 3D scanner demonstrated relatively similar values, while the DI3D system showed slightly different values. All 5 methods demonstrated good accuracy and had a high coefficient of reliability (>0.92) and a low technical error (<0.9 mm). The measured value of the distance between the right and left medial canthus obtained by using the DI3D system was statistically significantly different from that obtained by using the digital caliper, digitizer and laser scanner (p < 0.05), but the other measured values were not significantly different. On evaluating the reproducibility of measurement methods, two measurement values (Ls-Li, G-Pg) obtained by using direct anthropometry, one measurement value (N'-Prn) obtained by using the digitizer, and four measurement values (EnRt-EnLt, AlaRt-AlaLt, ChRt-ChLt, Sn-Pg) obtained by using the DI3D system, were statistically significantly different. However, the mean measurement error in every measurement method was low (<0.7 mm). All measurement values obtained by using the 3D CT and 3D scanner did not show any statistically significant difference. CONCLUSION: The results of this study show that all 3D facial soft tissue analysis methods demonstrate favorable accuracy and reproducibility, and hence they can be used in clinical practice and research studies.