Artificial intelligence as a prediction tool for orthognathic surgery assessment.

INTRODUCTION: An ideal orthodontic treatment involves qualitative and quantitative measurements of dental and skeletal components to evaluate patients' discrepancies, such as facial, occlusal, and functional characteristics. Deciding between orthodontics and orthognathic surgery remains challenging, especially in borderline patients. Advances in technology are aiding clinical decisions in orthodontics. The increasing availability of data and the era of big data enable the use of artificial intelligence to guide clinicians' diagnoses. This study aims to test the capacity of different machine learning (ML) models to predict whether orthognathic surgery or orthodontics treatment is required, using soft and hard tissue cephalometric values. METHODS: A total of 920 lateral radiographs from patients previously treated with either conventional orthodontics or in combination with orthognathic surgery were used, comprising n = 558 Class II and n = 362 Class III patients, respectively. Thirty-two measures were obtained from each cephalogram at the initial appointment. The subjects were randomly divided into training (n = 552), validation (n = 183), and test (n = 185) datasets, both as an entire sample and divided into Class II and Class III sub-groups. The extracted data were evaluated using 10 machine learning models and by a four-expert panel consisting of orthodontists (n = 2) and surgeons (n = 2). RESULTS: The combined prediction of 10 models showed top-ranked performance in the testing dataset for accuracy, F1-score, and AUC (entire sample: 0.707, 0.706, 0.791; Class II: 0.759, 0.758, 0.824; Class III: 0.822, 0.807, 0.89). CONCLUSIONS: The proposed combined 10 ML approach model accurately predicted the need for orthognathic surgery, showing better performance in Class III patients.

Establishment of the mid-sagittal reference plane for three-dimensional assessment of facial asymmetry: a systematic review : Establishment of the mid-sagittal reference plane: a systematic review.

OBJECTIVE: To systematically review the literature for mid-sagittal plane establishment approaches to identify the most effective method for constructing the mid-sagittal plane for the evaluation of facial asymmetry. MATERIALS AND METHODS: Six electronic databases (PubMed, Medline (via Ovid), EMBASE (via Ovid), Cochrane Library, Web of Science, and Scopus) and grey literature were searched for the studies that computed the mid-sagittal reference plane three-dimensionally, using a combination of MeSH terms and keywords. The methodological quality and the level of evidence for the included studies were analyzed using QUADAS-2 and GRADE, respectively. RESULTS: The preliminary search yielded 6746 records, of which 42 articles that met the predefined inclusion criteria were included in the final analysis. All the included articles reported the construction of the mid-sagittal reference plane (MSP) using varied methods. The risk of bias and concerns regarding the applicability of the included studies were judged to be 'low'. The level of evidence was determined to be 'low' for the effectiveness of the technique and 'moderate' for the ease of clinical applicability. CONCLUSION: Despite methodological heterogeneity, this review substantiates the comparable efficacy of cephalometric and morphometric MSP construction methods. A fully automated morphometric MSP holds promise as a viable option for routine clinical use. Nevertheless, future prospective studies with an emphasis on the impact, accuracy, and clinical applicability of MSP construction techniques in cases of facial asymmetry are required. CLINICAL RELEVANCE: The present review will assist clinicians in selecting the most suitable method for MSP construction, leading to improved treatment planning and ultimately more favorable treatment outcomes.

Assessment of accuracy and reproducibility of cephalometric identification performed by 2 artificial intelligence-driven tracing applications and human examiners.

OBJECTIVE: To assess the accuracy and reproducibility of cephalometric landmark identification performed by 2 artificial intelligence (AI)-driven applications (CefBot and WebCeph) and human examiners. STUDY DESIGN: Lateral cephalometric radiographs of 10 skulls containing 0.5 mm lead spheres directly placed at 10 cephalometric landmarks were obtained as the reference standard. Ten radiographs without spheres were obtained from the same skulls for identification of cephalometric points performed by the AI applications and 10 examiners. The x- and y-coordinate values of the cephalometric points identified by the AI applications and examiners were compared with those from the reference standard images using one-way analysis of variance and the Dunnet post-hoc test. The intraclass correlation coefficient (ICC) was used to evaluate reproducibility. Mean radial error (MRE) in identification was calculated with respect to the reference standard. Statistical significance was established at P < .05. RESULTS: Landmark identification by CefBot and the examiners did not exhibit significant differences from the reference standard on either axis (P > .05). WebCeph produced a significant difference (P < .05) in 4 and 6 points on the x- and y-axes, respectively. Reproducibility was excellent for CefBot and the examiners (ICC ≥ 0.9943) and good for WebCeph (ICC ≥ 0.7868). MREs of CefBot and the examiners were similar. CONCLUSION: With results similar to those of human examiners, CefBot demonstrated excellent reliability and can aid in cephalometric applications. WebCeph produced significant errors.

Feasibility of spheno-occipital synchondrosis fusion stages as an indicator for the assessment of maxillomandibular growth: A mixed longitudinal study.

OBJECTIVES: This study aimed to assess the relative growth rates (RGRs) of the maxilla and mandible at varying fusion stages of the spheno-occipital synchondrosis (SOS), thereby elucidating the potential of SOS stages in predicting maxillomandibular growth. MATERIALS AND METHODS: A total of 320 subjects (171 boys and 149 girls), aged 6 to 18 years, were retrospectively included. Each subject had a minimum of two longitudinal cone-beam computed tomography (CBCT) images, with no more than one interval of SOS fusion stage change between the two scans. Subjects were categorized based on their SOS fusion stages and genders. The RGRs of the maxilla and mandible at various SOS fusion stages were measured and compared using longitudinal CBCT images. RESULTS: Significant statistical differences were observed in maxillomandibular RGRs across various SOS fusion stages. In girls, the sagittal growth of the maxilla remained stable and active until SOS 3, subsequently exhibited deceleration in SOS 4-5 (compared to SOS 3-4, P < .05) and continued to decrease in SOS 5-6. Whereas in boys, the sagittal growth of the maxilla remained stable until SOS 4, and a deceleration trend emerged starting from SOS 5 to 6 (P < .01 compared to SOS 4-5). Mandibular growth patterns in both genders exhibited a progression of increasing-accelerating-decelerating rates from SOS 2 to 6. The highest RGRs for total mandibular length were observed in SOS 3-4 and SOS 4-5. CONCLUSION: Spheno-occipital synchondrosis fusion stages can serve as a valid indicator of maxillomandibular growth maturation.

Validation of a fully automatic three-dimensional assessment of orthognathic surgery.

The aim of the present study was to propose and validate FAST3D: a fully automatic three-dimensional (3D) assessment of the surgical accuracy and the long-term skeletal stability of orthognathic surgery. To validate FAST3D, the agreement between FAST3D and a validated state-of-the-art semi-automatic method was calculated by intra-class correlation coefficients (ICC) at a 95 % confidence interval. A one-sided hypothesis test was performed to evaluate whether the absolute discrepancy between the measurements produced by the two methods was statistically significantly below a clinically relevant error margin of 0.5 mm. Ten subjects (six male, four female; mean age 24.4 years), class II and III, who underwent a combined three-piece Le Fort I osteotomy, bilateral sagittal split osteotomy and genioplasty, were included in the validation study. The agreement between the two methods was excellent for all measurements, ICC range (0.85-1.00), and fair for the rotational stability of the chin, ICC = 0.54. The absolute discrepancy for all measurements was statistically significantly lower than the clinical relevant error margin (p < 0.008). Within the limitations of the present validation study, FAST3D demonstrated to be reliable and may be adopted whenever appropriate in order to reduce the work load of the medical staff.

The accuracy and reliability of different midsagittal planes in the symmetry assessment using cone-beam computed tomography.

Symmetry is an essential component of esthetic assessment. Accurate assessment of facial symmetry is critical to the treatment plan of orthognathic surgery and orthodontic treatment. However, there is no internationally accepted midsagittal plane (MSP) for orthodontists and orthognathic surgeons. The purpose of this study was to explore a clinically friendly MSP, which is more accurate and reliable than what is commonly used in symmetry assessment. Forty patients with symmetric craniofacial structures were analyzed on cone-beam computed tomography (CBCT) scans. The CBCT data were exported to the Simplant Pro software to build four reference planes that were constructed by nasion (N), basion (Ba), sella (S), odontoid (Dent), or incisive foramen (IF). A total of 31 landmarks were located to determine which reference plane is the most optimal MSP by comparing the asymmetry index (AI). The mean value of AI showed a significant difference (p < 0.05) among four reference planes. Also, the mean value of AI for all landmarks showed that Plane 2 (consisting of N, Ba, and IF) and Plane 4 (consisting of N, IF, and Dent) were more accurate and stable. In conclusion, the MSP consisting of N, Dent, and IF shows more accuracy and reliability than the other planes. Further, it is more clinically friendly because of its significant advantage in landmarking.

Evaluation of an objective staging system for assessment of cervical vertebral maturation.

BACKGROUND: The aim of this study was to evaluate an objective method for Cervical Vertebral Maturation (CVM) staging. METHODS: An initial sample of 647 Lateral Cephalometric Radiographs (LCR) were staged according to the CVM (Baccetti et al.) by 4 examiners. The final sample (n = 394) included LCR on which the staging of the 4 investigators matched. The objective staging was performed by a single operator. The sample was divided according to the maturational stages into pre-pubertal, pubertal and post-pubertal groups. Measurements were performed on the cervical vertebrae (C2, C3 and C4). The angle between posterior and superior borders for C3 and C4 was the Superior Wall Inclination Angle (SWIA). Concavity Depth (CD) for C2, C3 and C4, and Body Shape (BS) (ratio of width to height of C3 and C4). Measurements of the 3 groups were compared. RESULTS: Reliability of subjective staging was high (intra-observer reliability, 0.948; inter-observer reliability, 0.967). Good agreement was observed for the outcomes measured. Intra-observer reliability was good (0.918, 0.885 and 0.722 for CD, BS and SWIA, respectively). The same was for the inter-observer reliability results (0.902, 0.889 and 0.728 for CD, BS and SWIA, respectively). Significant differences were observed for mean values of SWIA and BS and median values of CD within maturational stage. Similar findings were observed when the outcomes were compared at different phases (P < 0.001). CONCLUSIONS: A standardized, objective staging system using linear, angular measurements and ratios was applied for the determination of cervical vertebral maturation.

Asymmetry in Class II subdivision malocclusion: Assessment based on 3D surface models.

INTRODUCTION: There is currently no consensus in the literature whether the aetiology of a Class II subdivision is dental, skeletal or both. The aim of this study was to identify and quantify skeletal and dental asymmetries in Class II subdivision malocclusions. METHODS: CBCTs from 33 Class II subdivision malocclusion patients were used to construct 3D volumetric label maps. Eighteen landmarks were identified. The original scan and associated 3D volumetric label map were mirrored. Registration of the original and mirrored images relative to the anterior cranial base, maxilla and mandible were performed. Surface models were generated, and 3D differences were quantified. Statistical analysis was performed. RESULTS: Anterior cranial base registration showed significant differences for fossa vertical difference, fossa roll, mandibular yaw, mandibular lateral displacement and lower midline displacement. Regional registrations showed significant differences for antero-posterior (A-P) mandibular length, maxillary roll, A-P maxillary first molar position, maxillary first molar yaw and maxillary first molar roll. Class II subdivision patients also show an asymmetric mandibular length as well as an asymmetric gonial angle. Moderate correlations were found between the A-P molar relationship and fossa A-P difference, mandibular first molar A-P difference, maxillary first molar A-P difference and maxillary first molar yaw. CONCLUSIONS: This study suggests that Class II subdivisions can result from both significant skeletal and dental factors. Skeletal factors include a shorter mandible as well as posterior and higher displacement of the fossa on the Class II side, resulting in mandibular yaw. Dental factors include maxillary and mandibular first molar antero-posterior asymmetry.

An automatic cephalometric landmark detection method based on heatmap regression and Monte Carlo dropout.

Cephalometric analysis plays an important role in orthodontic diagnosis and treatment planning. It depends on the detection of multiple landmarks, while the process is time-consuming and tedious. Although some deep learning-based automatic landmark detection algorithms have achieved excellent performance, most of them adopt multi-stage models increasing the complexity and detection time. Meanwhile, few studies focused on the uncertainty of detection results, thereby ignoring its significant clinical value. In this paper, we propose a novel approach based on heatmap regression for landmark detection, which can achieve competitive accuracy and good robustness with only one step. Furthermore, by applying Monte Carlo dropout to a U-shaped convolutional neural network, we can obtain not only the coordinate of each landmark but also the corresponding simple uncertainty, so that doctors can pay more attention to those landmarks with higher uncertainty. The evaluation results showed the mean radial error is 1.39±1.06mm and the average successful detection rate is 79.65%, 97.22% within 2mm, 4mm for the IEEE ISBI2015 Test Dataset 1, the indicators for the IEEE ISBI2015 Test Dataset 2 are 1.33±0.93mm, 80.05% and 97.53%, respectively. Our method has the potential to become an assistant tool in clinical practice. Automatic and accurate detection with uncertainty analysis is expected to help guide the doctor's judgment.

Assessment of landmark detection in cephalometric radiographs with different conditions of brightness and contrast using the an artificial intelligence software.

OBJECTIVES: To evaluate the reliability and reproducibility of an artificial intelligence (AI) software in identifying cephalometric points on lateral cephalometric radiographs considering four settings of brightness and contrast. METHODS AND MATERIALS: Brightness and contrast of 30 lateral cephalometric radiographs were adjusted into four different settings. Then, the control examiner (ECont), the calibrated examiner (ECal), and the CEFBOT AI software (AIs) each marked 19 cephalometric points on all radiographs. Reliability was assessed with a second analysis of the radiographs 15 days after the first one. Statistical significance was set at p < 0.05. RESULTS: Reliability of landmark identification was excellent for the human examiners and the AIs regardless of the type of brightness and contrast setting (mean intraclass correlation coefficient >0.89). When ECont and ECal were compared for reproducibility, there were more cephalometric points with significant differences on the x-axis of the image with the highest contrast and the lowest brightness, namely N(p = 0.033), S(p = 0.030), Po(p < 0.001), and Pog'(p = 0.012). Between ECont and AIs, there were more cephalometric points with significant differences on the image with the highest contrast and the lowest brightness, namely N(p = 0.034), Or(p = 0.048), Po(p < 0.001), A(p = 0.042), Pog'(p = 0.004), Ll(p = 0.005), Ul(p < 0.001), and Sn(p = 0.001). CONCLUSIONS: While the reliability of the AIs for cephalometric landmark identification was rated as excellent, low brightness and high contrast seemed to affect its reproducibility. The experienced human examiner, on the other hand, did not show such faulty reproducibility; therefore, the AIs used in this study is an excellent auxiliary tool for cephalometric analysis, but still depends on human supervision to be clinically reliable.

The psc-CVM assessment system: A three-stage type system for CVM assessment based on deep learning.

BACKGROUND: Many scholars have proven cervical vertebral maturation (CVM) method can predict the growth and development and assist in choosing the best time for treatment. However, assessing CVM is a complex process. The experience and seniority of the clinicians have an enormous impact on judgment. This study aims to establish a fully automated, high-accuracy CVM assessment system called the psc-CVM assessment system, based on deep learning, to provide valuable reference information for the growth period determination. METHODS: This study used 10,200 lateral cephalograms as the data set (7111 in train set, 1544 in validation set and 1545 in test set) to train the system. The psc-CVM assessment system is designed as three parts with different roles, each operating in a specific order. 1) Position Network for locating the position of cervical vertebrae; 2) Shape Recognition Network for recognizing and extracting the shapes of cervical vertebrae; and 3) CVM Assessment Network for assessing CVM according to the shapes of cervical vertebrae. Statistical analysis was conducted to detect the performance of the system and the agreement of CVM assessment between the system and the expert panel. Heat maps were analyzed to understand better what the system had learned. The area of the third (C3), fourth (C4) cervical vertebrae and the lower edge of second (C2) cervical vertebrae were activated when the system was assessing the images. RESULTS: The system has achieved good performance for CVM assessment with an average AUC (the area under the curve) of 0.94 and total accuracy of 70.42%, as evaluated on the test set. The Cohen's Kappa between the system and the expert panel is 0.645. The weighted Kappa between the system and the expert panel is 0.844. The overall ICC between the psc-CVM assessment system and the expert panel was 0.946. The F1 score rank for the psc-CVM assessment system was: CVS (cervical vertebral maturation stage) 6 > CVS1 > CVS4 > CVS5 > CVS3 > CVS2. CONCLUSIONS: The results showed that the psc-CVM assessment system achieved high accuracy in CVM assessment. The system in this study was significantly consistent with expert panels in CVM assessment, indicating that the system can be used as an efficient, accurate, and stable diagnostic aid to provide a clinical aid for determining growth and developmental stages by CVM.

Tridimensional assessment of the mandibular angle in patients with different skeletal patterns by cone-beam computed tomography scans: a retrospective study.

BACKGROUND: Since the muscles of chewing are involved in the region of the mandibular angle, important structures in surgical and orthodontic procedures, to study its morphological aspects and the possible influence of different patterns of skeletal development would be of interest. Thus, this study aimed to assess the influence of patient characteristics - such as sex, skeletal malocclusion (Class I, Class II, and Class III) and facial type (brachycephalic, mesocephalic, and dolichocephalic) - on the width, height, thickness, and volume of the mandibular angle, using cone-beam computed tomography (CBCT) scans. METHODS: CBCT scans were assessed - 144 men and 154 women, total of 298 - and classified according to skeletal patterns (skeletal malocclusions and facial types). Width, height, and thickness of the mandibular angle were measured using OnDemand 3D software. The volumetric measures of the mandibular angle were obtained using the ITK-SNAP software. Analysis of Variance (multiway ANOVA) with Tukey's post-hoc test compared the data, with a 5% significance level. RESULTS: Among the factors studied, sex significantly influenced all the analyzed variables (height, width, thickness, and volume of the mandibular angle) (p < 0.05); in general, male individuals presented higher values than females. In some cases, the skeletal malocclusion and facial type factors influenced only the width and height variables (p < 0.05); in general, the Class III and dolichocephalic individuals presented higher values in relation to the other types of skeletal malocclusions and facial types. CONCLUSIONS: Variations in the craniofacial growth pattern, considering the different skeletal malocclusions and facial types, had some influence in the width and height dimensions of the mandibular angle. Furthermore, sex influenced all the studied variables.

Assessment of craniofacial growth in individuals with ectodermal dysplasia after complete denture rehabilitation: A preliminary study.

Aim: The main purpose was to evaluate the effect of complete denture rehabilitation on the jaw growth pattern in individuals with ectodermal dysplasia from an early age to maturity. Settings and Design: This was a prospective in vivo study performed in the Department of Prosthodontics, King George Medical University, Lucknow, India. Materials and Methods: Rehabilitation with three sets of conventional complete dentures was completed in an ectodermal dysplasia case at the age of 5, 10, and 17 years. Cephalometric and diagnostic cast analyses were the methods performed to evaluate jaw growth patterns. Linear and angular measurements obtained after denture rehabilitation were averaged and compared with mean standard values of nearly corresponding ages, as given by Sakamoto and Bolton. Conversely, alveolar ridge arch width and length were evaluated for their dimensional changes during the same age intervals. Statistical Analysis Used: Mann-Whitney U-test was used to check the difference between the groups. The significance of the level adopted was 5%. Results: Nasion-anterior nasal spine, anterior nasal spine-menton, anterior nasal spine-pterygomaxillary fissure, gonion-sella, and gonion-menton lengths were found to be not statistically significant than the mean standard values of nearly corresponding ages (P > 0.05). The decrease in facial plane angle, increase in Y-axis angle, and mandibular plane angle after complete denture rehabilitation were statistically significant when compared to their mean standard values (P < 0.05). Cast analysis showed more increase in the length compared to the width in both arches. Conclusion: Complete denture rehabilitation did not significantly affect the jaw growth pattern, although it improved facial esthetics and masticatory activity by establishing adequate vertical dimensions.

Clinical metrics and tools for provider assessment and tracking of trigonocephaly.

OBJECTIVE: Quantitative measurements of trigonocephaly can be used to characterize and track this phenotype, which is associated with metopic craniosynostosis. Traditionally, trigonocephaly metrics were extracted from CT scans; however, this method exposes patients to ionizing radiation. Three-dimensional optical scans are another option but are not routinely available in most outpatient settings. Recently, the authors developed semiautomated artificial intelligence algorithms that extract craniometric data from orthogonal 2D photographs. Although 2D photographs are safe, inexpensive, and straightforward to obtain, the accuracy of photograph-based craniometrics in comparison to CT and 3D optical scan correlates has not been established. In this study the authors compared the classification power of 2D photograph-based metrics of trigonocephaly with four CT-based metrics and one 3D optical scan-based metric in a heterogeneous series of patients who presented to an outpatient craniofacial clinic. METHODS: In this study the authors performed retrospective craniometric analyses of patient 2D photographs, 3D optical scans, and CT scans. Imaging-derived craniometrics include the 2D photograph-based anterior arc angle (AAA2D-photo), anterior-posterior ratio (APR2D-photo), and anterior-middle ratio (AMR2D-photo); the CT-based anterior arc angle (AAACT), metopic index (MICT), endocranial-bifrontal angle (eBFACT), and interfrontal angle (IFACT); and the 3D optical scan-based anterior arc angle (AAA3D-optical). Receiver operating characteristics (ROCs) were used to identify craniometrics strongly descriptive of trigonocephaly. Interrater comparisons were made between paired trigonocephaly measurements obtained from photographs and either CT scans or 3D optical scans. RESULTS: There were 13 photograph-based and CT-based pairs and 22 paired measurements from 2D photographs and 3D optical scans. AAA displayed the strongest classification capacity across all three imaging modalities. Significant agreement was observed between AAACT and AAA2D-photo (intraclass correlation coefficient [ICC] = 0.68 [95% CI 0.24-0.89], p = 0.0035), and AAA3D-optical and AAA2D-photo (ICC = 0.70 [95% CI 0.41-0.87], p < 0.0001). There was no significant correlation between APR2D-photo or AMR2D-photo and conventional CT-based metrics describing longitudinal width ratios (MICT). CONCLUSIONS: Photograph-based craniometrics are powerful tools that can be used to quantify the severity of trigonocephaly and exhibit high concordance with standard measurements derived from CT scans and 3D optical scans. The authors developed and freely share a research-use application to calculate trigonocephaly metrics from 2D photographs. Given the availability of digital photography, lack of ionizing radiation, and low cost of photograph-based craniometric derivation, this technique may be useful to supplement routine ambulatory care and objectively track outcomes following treatment.

Three-dimensional radiographic assessment of the mandibular retromolar donor site in different vertical facial growth types.

PURPOSE: To assess volumetrically, the impact of vertical facial growth types (VGFT) on the retromolar area as a bone donor site MATERIAL AND METHODS: 60 cone beam computed tomography (CBCT) scans of adult individuals were classified in three groups according to their SN-GoGn angle: hypodivergent group (hG) (33.33%), normodivergent group (NG) (30%) and hyperdivergent group (HG) (36.67%). Total harvestable bone volume and surface (TBV and TBS respectively), total cortical and cancellous bone volume (TCBV and TcBV respectively) and the percentage of cortical and cancellous bone volume (CBV and cBV respectively) were evaluated. RESULTS: The whole sample showed a mean TBV of 1220.99±448.81mm³ and a mean TBS of 940.29±259.93mm². Statistically significant differences were found between the different outcome variables and the vertical growth patterns (p<0.001). TBS differs for the different vertical growth patterns with the highest mean of TBS observed in the hG group. TBV also significantly differs between the different vertical growth patterns (p<0.001) with the highest mean observed for the hG individuals. Significant differences in percentages of cBV and CBV were present between the hyper-divergent groups and the other groups (p<0.001) with the hyper-divergent group having the lowest percentage of CBV and the highest percentage of cBV. CONCLUSION: hypodivergent individuals tend to have thicker bone blocks that can be used in onlay technique while thinner bone blocks harvested from hyperdivergent and normodivergent individuals can be used in three-dimensional grafting approach.

In vivo three-dimensional cephalometric landmarks using CBCT for assessment of condylar volume and surface in individuals with Class I, II, and III malocclusions.

OBJECTIVE: To assess volume and surface of the mandibular condyle on cone beam computed tomography (CBCT) scans by comparing Class I, II, and III malocclusions. METHODS: CBCT scans of 55 patients were assessed to measure ANB angle, condyle volume, and surface by using VistaDent software. The values were compared between the different skeletal malocclusions and correlated to gender and sides. Kruskal-Wallis test was used for comparison of malocclusions and Mann-Whitney test and Wilcoxon test for comparisons of genders and sides. Statistical significance was defined as p < 0.05. RESULTS: There were no significant differences in volume (p = 0.588) and surface (p = 0.830) between the malocclusion classes. The comparison between sides showed a statistically significant difference for surface (p = 0.038). CONCLUSION: Condylar volume and surface evaluated on CBCT scans showed no statistically different values for Class I, II, and III malocclusions.

Assessment of the Relation Between Craniofacial Tissue Profile-Morphology and Dermatoglyphics.

This study aims to evaluate the relationship between the convexity angle of facial tissue and fingerprint types by analyzing the connection between dermatoglyphic prints and facial structure. A total of 65 adults (24 females, 41 males) participated in the study. Each participant's fingerprint was analyzed using conventional methods of observation upon the index finger of the dominant hand. Fingerprints were classified into 3 fundamental types: arch, whorl, or loop. Craniofacial profiling was performed with measurements of hard tissue (Gl'-A-Pg') and soft tissue facial convexity (Gl-Sn-Pg) and total facial convexity (Gl-Prn-Pg) angles between 3 anthropological points determined on the lateral direct radiographs of the participants. Soft tissue convexity facial angle (Gl-Sn-Pg) values were found to be an average of 166.83° in females and an average of 162.05° in males. (Gl-Prn-Pg) values were found to be an average of 138.54° in females and 135.27° in males. The soft tissue profile of males showed a significantly convex structure compared with females. Also, the "whorl" type of fingerprint was found to be dominant in both sexes. There is no statistically significant difference in terms of soft tissue profile convexity in individuals belonging to the 3 different fingerprint groups. No statistically significant difference in soft tissue profile angular values between right-hand thumb and index fingerprint type groups were found among and between sexes. However, a comprehensive analysis of the relationships between the nose, lips, mouth, ear, and eyes and fingerprints of the same person may prove to be beneficial.

An objective, quantitative, dynamic assessment of facial movement symmetry changes after orthognathic surgery.

The aim of this study was to generate a quantitative dynamic assessment of facial movement symmetry changes after orthognathic surgery. Twenty-five patients diagnosed with skeletal class III malocclusion with facial asymmetry who underwent bimaxillary surgery were recruited. The patients were asked to perform a maximum smile that was recorded using a three-dimensional facial motion capture system preoperatively (T0), 6 months postoperatively (T1), and 12 months postoperatively (T2). Eleven facial landmarks were selected to analyse the cumulative distance and average speed during smiling. The absolute differences for the paired landmarks between the sides were analysed to reflect the symmetry changes. The results showed that the asymmetry index of the cheilions at T2 was significantly lower than that at T0 (P = 0.004), as was the index of the mid-lateral lower lips (P = 0.006). The mean difference in cheilions was 2.13 ±â€¯1.41 mm at T0, 1.33 ±â€¯1.09 mm at T1, and 1.00 ±â€¯0.98 mm at T2. The facial total mobility at T1 was significantly lower than that at T0 (P < 0.001), while the total mobility at T2 was significantly higher than that at T1 (P = 0.012). The orthognathic surgical correction of facial asymmetry was able to improve the associated asymmetry of facial movements.

A Simple and Descriptive Assessment of Morphology Based on the Horizontal Plane of the Pediatric Head and Creation of a Normative Database in Japanese Children 6 Years Old and under: Horizontal Vector Analysis.

We herein introduce horizontal vector analysis, a simple method for assessing cranial morphology based on measurement of the head's horizontal plane, and use this method to establish normal cranial morphology in Japanese children Computed tomography scans taken in 2010-2019 in healthy Japanese children aged ≤ 6 years. The two measurement planes were parallel to the orbitomeatal plane: namely, a plane passing through the dorsum sellae (DS) and the plane superior to that with the maximal area (Max plane). A protractor was used to circumferentially measure the lengths from the central point to the outer surface of the skull. A total of 487 images were extracted. The distances between the DS and Max planes were consistently almost 30 mm for each age group, so we fixed the Max plane as the plane 30 mm superior to the DS plane. Finally, we established datasets of normal values for each age group and sex. Using these norms, perioperative evaluation of various cranial deformities could be performed more easily and circumstantially.

Assessment of soft-tissue vs hard-tissue changes after isolated functional genioplasty / Évaluation des modifications des tissus mous par rapport aux tissus durs après une génioplastie fonctionnelle isolée

Introduction: This study aimed to determine the vertical and horizontal soft-tissue vs hard-tissue changes after isolated functional genioplasty and to revisit hard-tissue remodeling at the symphysis. Methods: Seventy-five patients who underwent genioplasty as an isolated procedure at the end of their orthodontic treatment were divided into three groups on the basis of their age at surgery: < 15 years (group 1), 15-18 years (group 2) and ≥ 19 years (group 3). Patients were evaluated at three time points: immediately before surgery (T1), immediately after surgery (T2) and two years after surgery (T3). In addition, 25 patients who did not accept genioplasty, were age-matched with group 1, and had a follow-up radiograph two years after the end of their orthodontic treatment were used as a control group. Results: From T2 to T3, group 1 showed less forward horizontal hard-tissue and soft-tissue changes at pogonion (Pg) than the control group; however, no difference was noted for vertical changes at Me & Me'. From T1 to T3, the horizontal hard-tissue and soft-tissue changes at Pg were 6.39 mm and 6.72 mm, respectively, for surgical groups. Vertical hard-tissue change at menton (Me) showed a reduction of 1.63 mm (95% confidence interval [CI], -3.37 to 0.11) and 3.89 mm (95% CI, -5.83 to -1.95) in nongrowing female and male patients, respectively. The vertical soft-tissue change reduction was similar for nongrowing male and female patients (1.7 mm [95% CI, -2.96 to -0.45]). Soft-tissue thickness change at Pg (0.33 mm) was not significant. In contrast, a small but significant increase in soft-tissue thickness was noted at Me (0.54 mm). Linear regressions were calculated for all groups and allowed for predicting long-term soft-tissue changes (T3-T1) using the amount of surgical displacement (T2-T1). Conclusions: The horizontal hard-tissue change was stable for nongrowing patients, and the horizontal soft-tissue change was 92% of hard-tissue. Vertical soft-tissue change is less predictable. Variation of soft-tissue thickness after genioplasty can be explained by skeletal changes and the achievement of an unforced labial occlusion. These results support the functional and esthetic benefits of this surgery. Comparison with the control group showed that genioplasty does not change the growth pattern, and bone remodeling is likely to explain the difference noted at Pg.

Introduction: Cette étude avait pour but de déterminer les modifications verticales et horizontales des tissus cutanés par rapport aux tissus osseux après une génioplastie fonctionnelle isolée et d'évaluer le remodelage des tissus osseux au niveau de la symphyse. Méthodes: Soixante-quinze patients qui ont subi une génioplastie comme procédure isolée à la fin de leur traitement orthodontique ont été divisés en trois groupes sur la base de leur âge au moment de la chirurgie : moins de 15 ans (groupe 1), de 15 à 18 ans (groupe 2) et de 19 ans et plus (groupe 3). Les patients ont été évalués à trois moments : immédiatement avant la chirurgie (T1), immédiatement après la chirurgie (T2) et deux ans après la chirurgie (T3). En outre, 25 patients qui n'ont pas accepté la génioplastie, dont l'âge correspondait à celui du groupe 1 et qui ont subi une téléradiographie de profil de contrôle deux ans après la fin de leur traitement orthodontique ont été utilisés comme groupe témoin. Résultats: De T2 à T3, le groupe 1 a montré moins de changements horizontaux des tissus durs et mous vers l'avant au niveau du pogonion (Pg) que le groupe témoin ; cependant, aucune différence n'a été notée pour les changements verticaux au niveau de Me & Me'. De T1 à T3, les changements horizontaux des tissus osseux et cutanés à Pg étaient respectivement de 6,39 mm et 6,72 mm pour les groupes chirurgicaux. La modification verticale des tissus osseux au niveau du menton (Me) a montré une réduction de 1,63 mm (IC 95 %, -3,37 à 0,11) et de 3,89 mm (IC95 %, -5,83 à -1,95) chez les patients féminins et masculins sans croissance, respectivement. La réduction verticale de la modification des tissus mous était similaire chez les patients homme et femme qui ne sont pas en croissance (1,7 mm [IC 95 %, -2,96 à -0,45]). La modification de l'épaisseur des tissus mous à Pg (0,33 mm) n'était pas significative. En revanche, une augmentation faible mais significative de l'épaisseur des tissus cutanés a été observée à Me (0,54 mm). Des régressions linéaires ont été calculées pour tous les groupes et permettent de prédire les changements à long terme des tissus cutanés (T3-T1) en utilisant la quantité de déplacement chirurgical (T2-T1). Conclusions: Le changement horizontal des tissus osseux est stable pour les patients qui ne grandissent pas et le changement horizontal des tissus mous représente 92 % des tissus durs. Le changement vertical des tissus cutanés est moins prévisible. La variation de l'épaisseur des tissus cutanés après une génioplastie peut s'expliquer par les changements squelettiques et l'obtention d'une occlusion labiale non forcée. Ces résultats confirment les avantages fonctionnels et esthétiques de cette chirurgie. La comparaison avec le groupe témoin a montré que la génioplastie ne modifie pas le schéma de croissance et le remodelage osseux est susceptible d'expliquer la différence constatée à Pg.