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Mielke, Falk, Eli Amson, and John A. Nyakatura. "Morpho-Functional Analysis Using Procrustes Superimposition by Static Reference." Evolutionary Biology 45, no. 4 (2018): 449–61. http://dx.doi.org/10.1007/s11692-018-9456-9.
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Webster, Mark, and H. David Sheets. "A Practical Introduction to Landmark-Based Geometric Morphometrics." Paleontological Society Papers 16 (October 2010): 163–88. http://dx.doi.org/10.1017/s1089332600001868.
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Landmark-based geometric morphometrics is a powerful approach to quantifying biological shape, shape variation, and covariation of shape with other biotic or abiotic variables or factors. The resulting graphical representations of shape differences are visually appealing and intuitive. This paper serves as an introduction to common exploratory and confirmatory techniques in landmark-based geometric morphometrics. The issues most frequently faced by (paleo)biologists conducting studies of comparative morphology are covered. Acquisition of landmark and semilandmark data is discussed. There are several methods for superimposing landmark configurations, differing in how and in the degree to which among-configuration differences in location, scale, and size are removed. Partial Procrustes superimposition is the most widely used superimposition method and forms the basis for many subsequent operations in geometric morphometrics. Shape variation among superimposed configurations can be visualized as a scatter plot of landmark coordinates, as vectors of landmark displacement, as a thin-plate spline deformation grid, or through a principal components analysis of landmark coordinates or warp scores. The amount of difference in shape between two configurations can be quantified as the partial Procrustes distance; and shape variation within a sample can be quantified as the average partial Procrustes distance from the sample mean. Statistical testing of difference in mean shape between samples using warp scores as variables can be achieved through a standard Hotelling's T2 test, MANOVA, or canonical variates analysis (CVA). A nonparametric equivalent to MANOVA or Goodall's F-test can be used in analysis of Procrustes coordinates or Procrustes distance, respectively. CVA can also be used to determine the confidence with which a priori specimen classification is supported by shape data, and to assign unclassified specimens to pre-defined groups (assuming that the specimen actually belongs in one of the pre-defined groups).Examples involving Cambrian olenelloid trilobites are used to illustrate how the various techniques work and their practical application to data. Mathematical details of the techniques are provided as supplemental online material. A guide to conducting the analyses in the free Integrated Morphometrics Package software is provided in the appendix.
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Rohlf, F. James, and Dennis Slice. "Extensions of the Procrustes Method for the Optimal Superimposition of Landmarks." Systematic Zoology 39, no. 1 (1990): 40. http://dx.doi.org/10.2307/2992207.
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Kim, Na-Ri, Soo-Byung Park, Sang Min Shin, et al. "Preliminary Study to Determine the Reference Plane of Patients with a Unilateral Cleft Lip and Palate." Cleft Palate-Craniofacial Journal 54, no. 6 (2017): 707–14. http://dx.doi.org/10.1597/16-026.
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Objective The objective of this study was to determine the three-dimensional midsagittal reference planes for unilateral cleft lip and palate (UCLP) patients that can be easily applied in a clinical setting. Design This was a retrospective analysis. Patients There were 35 UCLP patients (25 men, 10 women; 28.1 ± 6.9 years old) in this study. Methods With landmark's three-dimensional coordinates obtained from cone-beam computed tomography, the symmetric midsagittal reference planes were calculated by applying the ordinary Procrustes superimposition method using the original and mirror images. Procrustes analysis was also used to find the closest landmarks to the calculated symmetric midsagittal reference plane and test its compatibility with the symmetrical midsagittal reference plane. Main Outcome Measure The three nearest landmarks to the symmetric midsagittal reference plane were Opisthion, Basion, and Nasion. Results The averages of the sums of the squared Euclidean distance and squared Procrustes distance differences between the two configurations and shapes fabricated by the symmetrical and landmark-based midsagittal reference planes, respectively, were calculated as 1.836 ± 3.295 and 1.519 × 10–5 ± 2.351 × 10–5. Conclusion It was confirmed that the midsagittal reference planes from these selected landmarks for UCLP patients were compatible with symmetric midsagittal reference planes from the Procrustes analysis and the asymmetric measurements.
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Touzé, Romain, Yann Heuzé, Matthieu P. Robert, et al. "Extraocular muscle positions in anterior plagiocephaly: V-pattern strabismus explained using geometric mophometrics." British Journal of Ophthalmology 104, no. 8 (2019): 1156–60. http://dx.doi.org/10.1136/bjophthalmol-2019-314989.
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IntroductionOphthalmological involvement in anterior plagiocephaly (AP) due to unicoronal synostosis (UCS) raises management challenges. Two abnormalities of the extraocular muscles (EOM) are commonly reported in UCS without objective quantification: (1) excyclorotation of the eye and (2) malposition of the trochlea of the superior oblique muscle. Here we aimed to assess the positions of the EOM in AP, using geometric morphometrics based on MRI data.Materials and methodsPatient files were listed using Dr WareHouse, a dedicated big data search engine. We included all patients with AP managed between 2013 and 2018, with an available digital preoperative MRI. MRIs from age-matched controls without craniofacial conditions were also included. We defined 13 orbital and skull base landmarks in order to model the 3D position of the EOM. Cephalometric analyses and geometric morphometrics with Procrustes superimposition and principal component analysis were used with the aim of defining specific EOM anomalies in UCS.ResultsWe included 15 preoperative and 7 postoperative MRIs from patients with UCS and 24 MRIs from age-matched controls. Cephalometric analyses, Procrustes superimposition and distance computations showed a significant shape difference for the position of the trochlea of the superior oblique muscle and an excyclorotation of the EOM.ConclusionsOur results confirm that UCS-associated anomalies of the superior oblique muscle function are associated with malposition of its trochlea in the roof of the orbit. This clinical anomaly supports the importance of MRI imaging in the surgical management of strabismus in patients with UCS.
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Goswami, Anjali, Akinobu Watanabe, Ryan N. Felice, Carla Bardua, Anne-Claire Fabre, and P. David Polly. "High-Density Morphometric Analysis of Shape and Integration: The Good, the Bad, and the Not-Really-a-Problem." Integrative and Comparative Biology 59, no. 3 (2019): 669–83. http://dx.doi.org/10.1093/icb/icz120.
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Abstract The field of comparative morphology has entered a new phase with the rapid generation of high-resolution three-dimensional (3D) data. With freely available 3D data of thousands of species, methods for quantifying morphology that harness this rich phenotypic information are quickly emerging. Among these techniques, high-density geometric morphometric approaches provide a powerful and versatile framework to robustly characterize shape and phenotypic integration, the covariances among morphological traits. These methods are particularly useful for analyses of complex structures and across disparate taxa, which may share few landmarks of unambiguous homology. However, high-density geometric morphometrics also brings challenges, for example, with statistical, but not biological, covariances imposed by placement and sliding of semilandmarks and registration methods such as Procrustes superimposition. Here, we present simulations and case studies of high-density datasets for squamates, birds, and caecilians that exemplify the promise and challenges of high-dimensional analyses of phenotypic integration and modularity. We assess: (1) the relative merits of “big” high-density geometric morphometrics data over traditional shape data; (2) the impact of Procrustes superimposition on analyses of integration and modularity; and (3) differences in patterns of integration between analyses using high-density geometric morphometrics and those using discrete landmarks. We demonstrate that for many skull regions, 20–30 landmarks and/or semilandmarks are needed to accurately characterize their shape variation, and landmark-only analyses do a particularly poor job of capturing shape variation in vault and rostrum bones. Procrustes superimposition can mask modularity, especially when landmarks covary in parallel directions, but this effect decreases with more biologically complex covariance patterns. The directional effect of landmark variation on the position of the centroid affects recovery of covariance patterns more than landmark number does. Landmark-only and landmark-plus-sliding-semilandmark analyses of integration are generally congruent in overall pattern of integration, but landmark-only analyses tend to show higher integration between adjacent bones, especially when landmarks placed on the sutures between bones introduces a boundary bias. Allometry may be a stronger influence on patterns of integration in landmark-only analyses, which show stronger integration prior to removal of allometric effects compared to analyses including semilandmarks. High-density geometric morphometrics has its challenges and drawbacks, but our analyses of simulated and empirical datasets demonstrate that these potential issues are unlikely to obscure genuine biological signal. Rather, high-density geometric morphometric data exceed traditional landmark-based methods in characterization of morphology and allow more nuanced comparisons across disparate taxa. Combined with the rapid increases in 3D data availability, high-density morphometric approaches have immense potential to propel a new class of studies of comparative morphology and phenotypic integration.
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Kim, I., M. E. Oliveira, W. J. Duncan, I. Cioffi, and M. Farella. "3D Assessment of Mandibular Growth Based on Image Registration: A Feasibility Study in a Rabbit Model." BioMed Research International 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/276128.
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Background.Our knowledge of mandibular growth mostly derives from cephalometric radiography, which has inherent limitations due to the two-dimensional (2D) nature of measurement.Objective.To assess 3D morphological changes occurring during growth in a rabbit mandible.Methods.Serial cone-beam computerised tomographic (CBCT) images were made of two New Zealand white rabbits, at baseline and eight weeks after surgical implantation of 1 mm diameter metallic spheres as fiducial markers. A third animal acted as an unoperated (no implant) control. CBCT images were segmented and registered in 3D (Implant Superimposition and Procrustes Method), and the remodelling pattern described used color maps. Registration accuracy was quantified by the maximal of the mean minimum distances and by the Hausdorff distance.Results.The mean error for image registration was 0.37 mm and never exceeded 1 mm. The implant-based superimposition showed most remodelling occurred at the mandibular ramus, with bone apposition posteriorly and vertical growth at the condyle.Conclusion.We propose a method to quantitatively describe bone remodelling in three dimensions, based on the use of bone implants as fiducial markers and CBCT as imaging modality. The method is feasible and represents a promising approach for experimental studies by comparing baseline growth patterns and testing the effects of growth-modification treatments.
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Kolbe, Sarah E., Rowan Lockwood, and Gene Hunt. "Does morphological variation buffer against extinction? A test using veneroid bivalves from the Plio-Pleistocene of Florida." Paleobiology 37, no. 3 (2011): 355–68. http://dx.doi.org/10.1666/09073.1.
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Although morphological variation is known to influence the evolutionary fates of species, the relationship between morphological variation and survivorship in the face of extinction-inducing perturbations is poorly understood. Here, we investigate this relationship for veneroid bivalves in association with the Plio-Pleistocene extinction in Florida. Fourteen pairs of related species were selected for analysis, with each pair including one species that survived the Plio-Pleistocene extinction and another that became extinct during the interval. Morphological landmark data were acquired for more than 1500 museum specimens, representing 19 localities that encompass four well-known Plio-Pleistocene units in the study region. Procrustes superimposition was applied to each sample, and overall multivariate variation was calculated as the mean squared partial Procrustes distance between specimens and their mean form. Morphological variation was calculated at three geographic scales for each species, and differences in variation between survivors and victims were examined within each species pair. Results indicate that species surviving the Plio-Pleistocene extinction were significantly more variable morphologically than victims. Greater morphological variation may promote survivorship by directly enhancing species adaptations to changing conditions or by permitting the occupation of a larger geographic range. Alternatively, high morphological variation and survivorship may both be mediated by a third variable, such as large geographic range.
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Natarajan, Srikant, Junaid Ahmed, Shravan Shetty, Nidhin Philip Jose, Sharada Chowdappa, and Kavery Chengappa. "Geometric Morphometric Shape Analysis of Mandibular Post-Canine Dentition." Applied Sciences 14, no. 2 (2024): 658. http://dx.doi.org/10.3390/app14020658.
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Background: Genetic and epigenetic alterations have significant impacts on the morphology of permanent mandibular premolars and molars. Geometric morphometry is a powerful technique, which can be utilized to identify specific landmarks that exhibit variation and that are associated with ancestry and dimorphism. Methods: The geometric and anatomic landmarks of mandibular premolars and molars were extracted from 3D digital replicas of diagnostic dental casts prepared for model analysis (n = 160). Tooth shape analysis was conducted using various techniques, including Procrustes superimposition, Procrustes ANOVA, discriminant function analysis, and the regression of shape over the centroid size. Results: Procrustes ANOVA showed that centroid size was not significantly different between the two sexes, but shape was significantly different in the two-cusp-type second premolars (p = 0.0035) and in the first/second molars (p < 0.001). The three-cusp type of the second premolars showed the highest degree of allometry, with 3.35%, followed by the mandibular second molars, with 3%, indicating that distal class types have a tendency to exhibit allometry. The distal and lingual components of the tooth showed more variability, and females tended to have sharper cusp configurations. Conclusions: This study shows how landmarks vary in permanent human post-canine dentition, a crucial finding for anatomic reconstruction and restorative dentistry. In particular, the molars and premolars of the mandible post-canine teeth are critical for achieving optimal masticatory efficiency and overall health. Additionally, a higher degree of allometry and the later formation of cusps correlate with greater shape variation, particularly on the distal and lingual sides. For precise restorative procedures, a thorough understanding of the anatomy of these teeth is required.
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Rutland, John W., Bradley N. Delman, Christopher Bellaire, et al. "Craniofacial Dysmorphology in Unilateral Coronal Synostosis Using Three-Dimensional Landmark-Based Analysis With Generalized Procrustes Superimposition." Journal of Craniofacial Surgery 32, no. 1 (2020): 16–20. http://dx.doi.org/10.1097/scs.0000000000006787.
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Petrova, Tereza, Andrzej Brudnicki, Magdalena Kotova, et al. "The Slavcleft: A Three-Center Study of the Outcome of Treatment of Cleft Lip and Palate Considering Palatal Shape." Journal of Clinical Medicine 12, no. 18 (2023): 5985. http://dx.doi.org/10.3390/jcm12185985.
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The degree of deviation of palatal shape from the norm may reflect facial growth disturbance in cleft lip and palate (CLP). The objective of this study was to compare the palatal morphology in children treated with different surgical protocols. Palatal shape was assessed with geometric morphometrics (GM) including Procrustes superimposition, principal component analysis (PCA), and permutation tests with 10,000 permutations, in 24 children treated with two-stage repair with a late palatoplasty (Prague group; mean age at assessment 8.9 years), 16 children after two-stage repair with early palatoplasty (Bratislava group; mean age 8.2 years), and 53 children treated with a one-stage repair (Warsaw group, mean age 10.3 years). The non-cleft control group comprised 60 children at 8.6 years. The first five principal components (PCs) accounted for a minimum of 5% of the total shape variability (65.9% in total). The Procrustes distance was largest for the Prague vs. Control pair and smallest for the Prague vs. Bratislava pair. Nonetheless, all intergroup differences were statistically significant (p < 0.01). One can conclude that variations in palatal shape roughly correspond to cephalometric and dental arch relationship findings from prior research. Among the children who underwent a one-stage repair of the complete cleft, their palatal morphology most closely resembled that of the non-cleft controls. Conversely, children who received late palatoplasty exhibited the greatest degree of deviation.
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Yu, Xiaonan, Bin Liu, Yuru Pei, and Tianmin Xu. "Evaluation of facial attractiveness for patients with malocclusion: A machine-learning technique employing Procrustes." Angle Orthodontist 84, no. 3 (2013): 410–16. http://dx.doi.org/10.2319/071513-516.1.
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ABSTRACT Objective: To establish an objective method for evaluating facial attractiveness from a set of orthodontic photographs. Materials and Methods: One hundred eight malocclusion patients randomly selected from six universities in China were randomly divided into nine groups, with each group containing an equal number of patients with Class I, II, and III malocclusions. Sixty-nine expert Chinese orthodontists ranked photographs of the patients (frontal, lateral, and frontal smiling photos) before and after orthodontic treatment from “most attractive” to “least attractive” in each group. A weighted mean ranking was then calculated for each patient, based on which a three-point scale was created. Procrustes superimposition was conducted on 101 landmarks identified on the photographs. A support vector regression (SVR) function was set up according to the coordinate values of identified landmarks of each photographic set and its corresponding grading. Its predictive ability was tested for each group in turn. Results: The average coincidence rate obtained for comparisons of the subjective ratings with the SVR evaluation was 71.8% according to 18 verification tests. Conclusions: Geometric morphometrics combined with SVR may be a prospective method for objective comprehensive evaluation of facial attractiveness in the near future.
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Agbolade, Olalekan, Azree Shahrel Ahmad, and . "A Two Dimensional Facial Features Analysis for Gender-based Comparison Using Morphometrics Approach." International Journal of Engineering & Technology 7, no. 4.31 (2018): 214–19. http://dx.doi.org/10.14419/ijet.v7i4.31.23370.
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Making a gender comparison between male and female is not a difficult task for human beings but the science of gender comparison of faces by humans is completely unfathomable due to commonality of gender comparison in both humans and other animal species. Significant gender differences between masculine and feminine exist in many facial regions such as eyes, nose, mouth, cheek and chin; which have not been critically looked into. This research characterizes and analyzes the gender comparison in the human face as a function of face features and identifies the features which contribute significantly to the uniqueness of the face using morphometrics techniques such as Principal Component Analysis (PCA), Thin-Plate Spline (TPS) Warping and Procrustes Superimposition (PS). The results demonstrate that the male face is significantly different from that of female based on the analysis of the selected facial features which provides the basis for gender-based comparison of faces.Â
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Bigliazzi, Renato, Eliana Ayala Walverde, Derly Tescaro Narciso de Oliveira, André Pinheiro de Magalhães Bertoz, and Kurt Faltin Junior. "Morphometric analysis of three normal facial types in mixed dentition using posteroanterior cephalometric radiographs: preliminary results." Acta Scientiarum. Health Sciences 39, no. 2 (2017): 227. http://dx.doi.org/10.4025/actascihealthsci.v39i2.34139.
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The aim of the present investigation was to evaluate the craniofacial features of subjects with normal occlusion with different vertical patterns in the mixed dentition using morphometric analysis (Thin-Plate Spline analysis - TPS) applied to posteroanterior (PA) films. The sample comprised 39 individuals (18 females and 21 males), all in mixed dentition, aged from 8.4 to 10 years with satisfactory occlusion and balanced profile and with no history of orthodontic or facial orthopedic treatment. The sample was divided into three groups (mesofacial, brachyfacial and dolichofacial) according to the facial types proposed by Ricketts (1989). The average craniofacial configurations of each study group were obtained by orthogonal superimposition of Procrustes, thereby eliminating size differences and allowing only shape differences between groups to be analyzed by viewing the TPS deformation grid. Significant differences were found among the three facial types but were more remarkable between mesofacials and dolichofacials than between mesofacials and brachyfacials. TPS morphometric analysis proved efficient for accurate visualization of transverse and vertical differences among facial types even before pubertal growth spurt. These differences cannot be easily detected by traditional posteroanterior cephalometry.
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Ruiz, Ferdinando, Pietro Venezia, Vincenzo Ronsivalle, et al. "Geometric Morphometric Analysis of Mandibular Symphysis Growth between 12 and 15 Years of Age in Class II Malocclusion Subjects." Life 13, no. 2 (2023): 543. http://dx.doi.org/10.3390/life13020543.
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The aim of the present paper was to evaluate the morphology changes of the mandibular symphysis (MS) in a longitudinal retrospective cohort of class II untreated subjects. The study sample included 120 subjects followed during normal growth and examined at the age of 12 (T0) and 15 (T1) years. MS was traced using two landmarks and ten sliding semi-landmarks. The acquired morphological data were processed via Procrustes superimposition that allowed to study variation and covariation in MS’form according to specific variables such as age, gender, and skeletal pattern. The first two principal components (PCs) described more than 90 % of the total morphological variation. Both types of form changes of the symphysis could be associated with the different skeletal vertical growth patterns. Age and sex did not interfere with the form of chin symphysis. Moreover, there was no significant covariation between initial MS morphology and form modifications. Clinicians should not expect to be faced with spontaneous changes of the form of the symphysis during the orthodontic treatment of adolescents.
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Chaiphongpachara, Tanawat, and Sedthapong Laojun. "Annual Variability of Wing Morphology in Culex sitiens Wiedemann (Diptera, Culicidae) Mosquito Vectors from the Coastal Area of Samut Songkhram Province, Thailand." Journal of Parasitology Research 2019 (March 3, 2019): 1–7. http://dx.doi.org/10.1155/2019/3978965.
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Culex sitiens Wiedemann (Diptera, Culicidae) is a mosquito vector that is found in coastal areas. Effective control of mosquitoes requires knowledge of the biology, ecology, and behavior of the vector as well as of various other aspects, including its morphology. Currently, variations in the wing size and shape of coastal Cx. sitiens have not been described. Here, morphological changes were studied in the wings of Cx. sitiens from a coastal area of Samut Songkhram Province, Thailand. Samples were collected at night (6:00 pm–6:00 am) during single weeks of September in the years 2015–2017 using Center for Disease Control light traps with dry ice as bait. Eighteen landmarks of each individual were selected and digitized for landmark-based geometric morphometric analyses. Wing size variability was estimated using the isometric estimator of centroid size. Wing-shape variables were computed as Procrustes superimposition with residual coordinates of the 18 landmarks following a Generalized Procrustes Analysis and the principal components of residual coordinates. Degrees of wing-shape dissimilarity among individuals were analyzed using discriminant analysis or canonical variate analysis, which was illustrated in a discriminant space of canonical variables. Differences in wing size and shape among populations were calculated using nonparametric permutations based on 1000 runs with Bonferroni correction tests at a p-value of <0.05. The wing sizes and shapes of the mosquitoes differed significantly between observation years in all population groups, as indicated by nonparametric tests (1000 runs) with the Bonferroni correction. Differing rainfall between observation years was related to morphological changes in mosquito populations, presumably reflecting environmental adaptation. Differences in the wing morphology of Cx. sitiens between annual populations reflect adaptation to environmental variables such as rainfall and may affect the potential to act as insect vectors of human disease. These observations may facilitate the development of tools for managing mosquito-borne disease.
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Shidurkar, Dr Suraj, Dr Pooja Sharma, Dr Atul Singh, Dr Omkar Singh Yadav, Dr Ketki Dalvi, and Dr Banashree Saha. "A Cephalometric Study Of Vertical Skeletal Changes After Extraction And Non-Extraction Fixed Orthodontic Treatment Of Class I Malocclusion In North Indian Population." IOSR Journal of Dental and Medical Sciences 23, no. 10 (2024): 01–11. http://dx.doi.org/10.9790/0853-2310050111.
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Background: Orthodontic treatments frequently involve tooth extractions to address crowding and protrusion, but the effects of these extractions on vertical skeletal changes are still debated. Research has extensively covered aspects like soft tissue response and smile aesthetics, yet there is no consensus on their impact on vertical dimensions. This issue is particularly pertinent for hyperdivergent individuals, who make up about 22% of orthodontic patients. A proposed technique for such cases includes counterclockwise rotation of the lower jaw and advancement of posterior teeth to manage open bites or excessive vertical facial height. This study aims to compare vertical skeletal changes in Class I malocclusion patients undergoing extraction versus non-extraction fixed orthodontic treatments. Material and Methods: We analysed pre- and post-treatment lateral cephalometric radiographs from 60 Class I crowding patients, evenly split into extraction and non-extraction groups. Eight vertical skeletal parameters were assessed and compared statistically between the two groups. Superimposition analysis of radiograph tracings was used to explore vertical changes related to molar mesialization, particularly in the extraction group. Results: The extraction group demonstrated significant reductions in vertical skeletal dimensions compared to the non-extraction group. Measurements including FMA, SN-GoGn, Y-axis, SN-PP, and PP-MP showed significant differences, with reductions in the extraction group (P = 0.001). Procrustes superimposition indicated effective molar mesialization in the extraction group, which was not observed in the non-extraction group. Conclusion: Extraction of first premolars in fixed orthodontic treatment leads to a notable decrease in vertical skeletal dimensions, in contrast to the slight increase seen with non-extraction treatments. This reduction is largely due to molar mesialization, which enhances vertical skeletal dimensions and treatment stability in Class I crowding cases.
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Toneva, Diana, Silviya Nikolova, Elena Tasheva-Terzieva, Dora Zlatareva, and Nikolai Lazarov. "A Geometric Morphometric Study on Sexual Dimorphism in Viscerocranium." Biology 11, no. 9 (2022): 1333. http://dx.doi.org/10.3390/biology11091333.
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The level of sexual dimorphism manifested by human bones is an important factor for development of effective sex estimation methods. The aim of the study was to investigate the sexual dimorphism in the size and shape of the viscerocranium using geometric morphometric techniques. It also aimed to explore the sex differences in distinct viscerocranial regions and to establish the most dimorphic region with regard to size and shape. Computed tomography images of 156 males and 184 females were used in the study. Three-dimensional coordinates of 31 landmarks were acquired. Five landmark configurations were constructed from the viscerocranium and its orbital, nasal, maxillary, and zygomatic region. Generalized Procrustes superimposition, principal component analysis, and discriminant analysis were applied to each configuration. The significance of the sex differences in size and shape was assessed and significant differences were found in all configurations. The highest accuracy was obtained from both shape and size of the whole viscerocranium. Based on size only, the highest accuracy was achieved by the nasal region. The accuracy based on shape was generally low for all configurations, but the highest result was attained by the orbital region. Hence, size is a better sex discriminator than shape.
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Woodard, Katerina, and Jiri Neustupa. "Geometric Morphometrics of Bilateral Asymmetry in Eunotia bilunaris (Eunotiales, Bacillariophyceae) as a Tool for the Quantitative Assessment of Teratogenic Deviations in Frustule Shapes." Symmetry 14, no. 1 (2021): 42. http://dx.doi.org/10.3390/sym14010042.
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A number of pennate diatom genera typically have teratogenic deformations of their siliceous frustules due to the effects of environmental stress, such as high concentrations of heavy metals and low pH. However, the quantitative assessment of these deformations has rarely been applied. One species in which aberrations have frequently been reported is Eunotia bilunaris, which typically has bilaterally symmetric frustules with dorso-ventral differentiation. In this study, we aimed to illustrate the geometric morphometric analysis of symmetry as a tool for assessing the severity of teratogenic deformations. These were quantified by Procrustes superimposition of equidistant points placed along the valvar outlines in pairs of configurations based on their bilateral reflection symmetry. The shape deformations were mostly confined to central parts of the ventral outlines and were captured both by the symmetric and asymmetric subspaces of the variation. The amount of bilateral asymmetry in individual cells was negatively related to frustule size via the allometric power law relationship, illustrating that asymmetry increased in the asexual diminution series. The presented analysis provides a framework for the quantitative assessment of frustule deformations in eunotioid diatoms that can be used for the comparative scoring of teratogenic deviations among cells, populations, or species.
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Lopes, Cassiane Furlan, Fabiano Stefanello, Christian Bugs, Cristina Stenert, Leonardo Maltchik, and José Ricardo Inacio Ribeiro. "Sexual dimorphism in Belostoma angustum Lauck (Insecta: Heteroptera: Belostomatidae) may be related to paternal care." Biological Journal of the Linnean Society 129, no. 2 (2019): 288–314. http://dx.doi.org/10.1093/biolinnean/blz178.
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Abstract The structures involved in parental care are often dimorphic. Female Belostoma angustum water bugs lay eggs on the hemelytra of their mates, where the eggs are brooded until hatching. Males use their hind legs to carry, aerate and protect the eggs. After controlling for covariance between variables, we fitted a series of structural equation models (SEMs) and evaluated the existence of sexual dimorphism in the size of the body and hind legs, in the shape and centroid size of the hemelytrum, and among the static allometry slopes of the size-related differences. Landmarks were used to capture phenotypic variation, by eliminating all non-shape variations with a Procrustes superimposition. Neither the shape of the hemelytrum nor its centroid size was related significantly to the aforementioned linear body measurements. Instead, the differences in the size of the hind legs were mediated by body dimensions only in males. We also found that males were wider and had longer heads than females, according to the SEM intercept values. Our findings suggest that sexual dimorphism in B. angustum may be related to a balance between sexual role reversal and viability costs.
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Bennett, C. Verity, and Anjali Goswami. "Morphometric Analysis of Cranial Shape in Fossil and Recent Euprimates." Anatomy Research International 2012 (May 7, 2012): 1–7. http://dx.doi.org/10.1155/2012/478903.
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Quantitative analysis of morphology allows for identification of subtle evolutionary patterns or convergences in anatomy that can aid ecological reconstructions of extinct taxa. This study explores diversity and convergence in cranial morphology across living and fossil primates using geometric morphometrics. 33 3D landmarks were gathered from 34 genera of euprimates (382 specimens), including the Eocene adapiforms Adapis and Leptadapis and Quaternary lemurs Archaeolemur, Palaeopropithecus, and Megaladapis. Landmark data was treated with Procrustes superimposition to remove all nonshape differences and then subjected to principal components analysis and linear discriminant function analysis. Haplorhines and strepsirrhines were well separated in morphospace along the major components of variation, largely reflecting differences in relative skull length and width and facial depth. Most adapiforms fell within or close to strepsirrhine space, while Quaternary lemurs deviated from extant strepsirrhines, either exploring new regions of morphospace or converging on haplorhines. Fossil taxa significantly increased the area of morphospace occupied by strepsirrhines. However, recent haplorhines showed significantly greater cranial disparity than strepsirrhines, even with the inclusion of the unusual Quaternary lemurs, demonstrating that differences in primate cranial disparity are likely real and not simply an artefact of recent megafaunal extinctions.
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Kanavakis, Georgios, Anna-Sofia Silvola, Demetrios Halazonetis, Raija Lähdesmäki, and Pertti Pirttiniemi. "Incisor Occlusion Affects Profile Shape Variation in Middle-Aged Adults." Journal of Clinical Medicine 10, no. 4 (2021): 800. http://dx.doi.org/10.3390/jcm10040800.
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Background: The aim of this study was to assess the effect of overjet and overbite on profile shape in middle–aged individuals. Methods: The study population comprised 1754 46-year-old individuals, members of the 1966 Northern Finland Birth Cohort. Their profile images were digitized using 48 landmarks and semi-landmarks. The subsequent landmark coordinates were then transformed to shape coordinates through Procrustes Superimposition, and final data were reduced into Principal Components (PCs) of shape. Overjet and overbite values were measured manually, during a clinical examination. A multivariate regression model was developed to evaluate the effect of overjet and overbite on profile shape. Results: The first nine PCs described more than 90% of profile shape variation in the sample and were used as the shape variables in all subsequent analyses. Overjet predicted 21.3% of profile shape in the entire sample (η2overjet = 0.213; p < 0.001), while the effect of overbite was weaker (η2overbite = 0.138; p < 0.001). In males, the equivalent effects were 22.6% for overjet and 14% for overbite, and in females, 25.5% and 13.5%, respectively. Conclusion: Incisor occlusion has a noteworthy effect on profile shape in middle-aged adults. Its impact becomes more significant taking into consideration the large variety of genetic and environmental factors affecting soft tissue profile.
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Dobreva, Denitsa, Nikolaos Gkantidis, Demetrios Halazonetis, Carlalberta Verna, and Georgios Kanavakis. "Smile Reproducibility and Its Relationship to Self-Perceived Smile Attractiveness." Biology 11, no. 5 (2022): 719. http://dx.doi.org/10.3390/biology11050719.
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The reproducibility of facial expressions has been previously explored, however, there is no detailed information regarding the reproducibility of lip morphology forming a social smile. In this study, we recruited 93 young adults, aged 21–35 years old, who agreed to participate in two consecutive study visits four weeks apart. On each visit, they were asked to perform a social smile, which was captured on a 3D facial image acquired using the 3dMD camera system. Assessments of self-perceived smile attractiveness were also performed using a VAS scale. Lip morphology, including smile shape, was described using 62 landmarks and semi-landmarks. A Procrustes superimposition of each set of smiling configurations (first and second visit) was performed and the Euclidean distance between each landmark set was calculated. A linear regression model was used to test the association between smile consistency and self-perceived smile attractiveness. The results show that the average landmark distance between sessions did not exceed 1.5 mm, indicating high repeatability, and that females presented approximately 15% higher smile consistecy than males (p < 0.05). There was no statistically significant association between smile consistency and self-perceived smile attractiveness (η2 = 0.015; p = 0.252), when controlling for the effect of sex and age.
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Tsolakis, Ioannis A., Christos Verikokos, Despoina Perrea, Konstantina Alexiou, Sotiria Gizani, and Apostolos I. Tsolakis. "Effect of Diet Consistency on Rat Mandibular Growth: A Geometric Morphometric and Linear Cephalometric Study." Biology 11, no. 6 (2022): 901. http://dx.doi.org/10.3390/biology11060901.
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Background: Our study intended to investigate the null hypothesis that there is no effect of diet consistency on rat mandibular growth. Methods: A total sample of 24 female wistar rats, 30 days old, was used in this study. In the first group, the rats were fed soft diet and in the second group, they were fed hard diet for 60 days. On the 60th day, the rats were sedated and lateral cephalometric X-rays were taken. Lateral cephalometric X-rays were digitized with 7 craniofacial landmarks for the linear measurements, as well as with 12 curves and 90 landmarks, of which 74 were semilandmarks and 16 were fixed landmarks for morphometric analysis. These landmarks were exposed to Procrustes superimposition and Principal Component Analysis (PCA) to describe the shape variability of the mandible. Results: Means measurements of the soft diet group compared to those of the hard diet group were significantly different in linear and morphometric analysis measurements. The soft diet group of wistar rats revealed significant changes on the condyle (smaller), the angle of the mandible, and on the body of the mandible. Conclusions: Diet consistency affects the craniofacial growth of rats. Soft diet could be responsible for less mandibular growth.
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Oliva, Giorgio, Vilma Pinchi, Ilenia Bianchi, et al. "Three-Dimensional Dental Analysis for Sex Estimation in the Italian Population: A Pilot Study Based on a Geometric Morphometric and Artificial Neural Network Approach." Healthcare 10, no. 1 (2021): 9. http://dx.doi.org/10.3390/healthcare10010009.
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Dental dimorphism can be used for discriminating sex in forensic contexts. Geometric morphometric analysis (GMA) allows the evaluation of the shape and size, separately, of uneven 3D objects. This study presents experiments using a novel combination of GMA and an artificial neural network (ANN) for sex classification, applied to premolars of Caucasian Italian adults (50 females and 50 males). General Procrustes superimposition (GPS) and the partial least square (PLS) method were performed, respectively, to study the shape variance between sexes and to eliminate landmark variations. The “set-aside” approach was used to assess the accuracy of the proposed neural networks. As the main findings of the pilot study, the proposed method applied to the first upper premolar correctly classified 90% of females and 73% of males of the test sample. The accuracy was 0.84 and 0.80 for the training and test samples, respectively. The sexual dimorphism resulting from GMA was low, although statistically significant. GMA combined with the ANN demonstrated better sex classification ability than previous odontometric or dental morphometric methods. Future research could overcome some limitations by considering a larger sample of subjects and other kinds of teeth and experimenting with the use of computer vision for automatic landmark positioning.
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Klingenberg, Christian Peter, Larry J. Leamy, Eric J. Routman, and James M. Cheverud. "Genetic Architecture of Mandible Shape in Mice: Effects of Quantitative Trait Loci Analyzed by Geometric Morphometrics." Genetics 157, no. 2 (2001): 785–802. http://dx.doi.org/10.1093/genetics/157.2.785.
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AbstractThis study introduces a new multivariate approach for analyzing the effects of quantitative trait loci (QTL) on shape and demonstrates this method for the mouse mandible. We quantified size and shape with the methods of geometric morphometrics, based on Procrustes superimposition of five morphological landmarks recorded on each mandible. Interval mapping for F2 mice originating from an intercross of the LG/J and SM/J inbred strains revealed 12 QTL for size, 25 QTL for shape, and 5 QTL for left-right asymmetry. Multivariate ordination of QTL effects by principal component analysis identified two recurrent features of shape variation, which involved the positions of the coronoid and angular processes relative to each other and to the rest of the mandible. These patterns are reminiscent of the knockout phenotypes of a number of genes involved in mandible development, although only a few of these are possible candidates for QTL in our study. The variation of shape effects among the QTL showed no evidence of clustering into distinct groups, as would be expected from theories of morphological integration. Further, for most QTL, additive and dominance effects on shape were markedly different, implying overdominance for specific features of shape. We conclude that geometric morphometrics offers a promising new approach to address problems at the interface of evolutionary and developmental genetics.
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Lee, Catherine T. H., Barry H. Grayson, Court B. Cutting, Lawrence E. Brecht, and Wen Yuan Lin. "Prepubertal Midface Growth in Unilateral Cleft Lip and Palate following Alveolar Molding and Gingivoperiosteoplasty." Cleft Palate-Craniofacial Journal 41, no. 4 (2004): 375–80. http://dx.doi.org/10.1597/03-037.1.
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Objectives To examine the long-term effect of nasoalveolar molding and gingivoperiosteoplasty (modified Millard type) on midface growth at prepuberty. Procedures In this retrospective study, 20 consecutive patients with a history of complete unilateral cleft lip and palate were evaluated. Ten patients had nasoalveolar molding and gingivoperiosteoplasty performed at lip closure; 10 control patients had nasoalveolar molding but no gingivoperiosteoplasty because of late start in treatment or poor compliance. A single surgeon (C.B.C.) performed all surgical procedures. Standardized lateral cephalometric radiographs were evaluated at two time periods: T1 at pre–bone-grafting age and T2 at prepuberty age. Superimposition and cephalometric analysis were undertaken to investigate the two groups. Two cephalometric reference planes, sella-nasion and basion-nasion, were used to assess the vertical and sagittal relations of the midface (ANS-PNS). The reference landmarks were procrustes fitted. The mean location and variance of ANS and PNS landmarks were computed. All results were analyzed by permutation test. Results No significant difference in mean location or variance of ANS-PNS in both vertical and sagittal planes at both T1 and T2 periods were found between the two groups (p > .05). Conclusions The results suggested that midface growth in sagittal or vertical planes (up to the age of 9 to 13 years) were not affected by presurgical alveolar molding and gingivoperiosteoplasty (Millard type).
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Wellens, Hans L. L., and Anne M. Kuijpers-Jagtman. "Connecting the new with the old: modifying the combined application of Procrustes superimposition and principal component analysis, to allow for comparison with traditional lateral cephalometric variables." European Journal of Orthodontics 38, no. 6 (2016): 569–76. http://dx.doi.org/10.1093/ejo/cjv096.
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Peil, Alessandra Carniato, and Rodrigo Aranda. "Potential Niche Modeling Distribution and Wing Geometric Morphometrics of Apis mellifera In The Brazilian Pantanal." Sociobiology 68, no. 2 (2021): 5629. http://dx.doi.org/10.13102/sociobiology.v68i2.5629.
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The ecological niche models can be important for biogeographic patterns and processes and geometric morphometrics involves identifying changes that have occurred and comparing them to other specimens from different places and/or environmental conditions, assessing whether the environment is influencing such change. The present work aimed to verify the potential model of distribution for Apis mellifera and analyze if there is variation in the geometric morphometrics in wing venation in the Pantanal. We followed the hypothesis that there is variation in the geometric morphometrics of wings and that the geographically closest groups are more similar. For niche modeling, 44 geographical points and 19 bioclimatic variables were used. For morphometrics, twenty-two anatomical landmarks were plotted at the intersection of the veins. The X and Y coordinates were standardized through Procrustes superimposition, and PCA and MANOVA tests were performed. The predictive model indicated that the center of the Pantanal plain shows the greater probability of occurrence for the species. The most important bioclimatic variables were: average temperature in the rainiest quarter (84%) and average annual temperature (72%). Morphometric analyzes indicate that there was variation between the most distant geographic points. The slight variation between some closely located points in the Pantanal can be related to individual reflections of colonies from other points, since the species has great dispersion capacity. Thus, the distribution of A. mellifera in the Pantanal is possibly related to temperature also accompanied by human occupation and the geometric morphometrics of its wings reflecting aspects of dispersion and population dynamics in the Brazilian Pantanal.
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Bianchi, Ilenia, Giorgio Oliva, Giulia Vitale, et al. "A Semi-Automatic Method on a Small Italian Sample for Estimating Sex Based on the Shape of the Crown of the Maxillary Posterior Teeth." Healthcare 11, no. 6 (2023): 845. http://dx.doi.org/10.3390/healthcare11060845.
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Teeth are known to be reliable substrates for human identification and are endowed with significant sexual dimorphism not only in the size but also in the shape of the crowns. In the preliminary phase of our study (already published in 2021), a novel sex estimation method based on dental morphometric geometric (GMA) analysis combined with the artificial neural network (ANN) was developed and validated on a single dental element (first upper premolar) with an accuracy rate of 80%. This study aims to experiment and validate the combination of GMA–ANN on the upper first and second left premolars and the upper left first molar to obtain a reliable classification model based on the sexual dimorphic traits of multiple maxillary teeth of Caucasian Italian adults (115 males and 115 females). A general procrustes superimposition (GPS) and principal component analysis (PCA) were performed to study the shape variance between the sexes and to reduce the data variations. The “set-aside” approach was used to validate the accuracy of the proposed ANN. As the main findings, the proposed method correctly classified 94% of females and 68% of males from the test sample and the overall accuracy gained was 82%, higher than the odontometric methods that similarly consider multiple teeth. The shape variation between male and female premolars represents the best dimorphic feature compared with the first upper molar. Future research could overcome some limitations by considering a larger sample of subjects and experimenting with the use of computer vision for automatic landmark positioning and should verify the present evidence in samples with different ancestry.
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Barour, Choukri, and Michel Baylac. "Geometric morphometric discrimination of the three African honeybee subspecies Apis mellifera intermissa, A. m. sahariensis and A. m. capensis (Hymenoptera, Apidae): Fore wing and hind wing landmark configurations." Journal of Hymenoptera Research 52 (October 28, 2016): 61–70. https://doi.org/10.3897/jhr.52.8787.
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In this study, a landmark-based geometric morphometric analysis was carried out on three honeybee subspecies: Apis m. intermissa and A. m. sahariensis collected from Algeria, and, as a reference, A. m. capensis collected from South Africa. The aim of this study was to discriminate honeybee subspecies by patterns of shape variation of fore and hind wings. A total of 540 wings from 270 honeybee workers were analyzed. Our results revealed very high cross-validation classification rates (96.7% based on fore wing shape and 99.6% based on the combination of fore and hind wing forms respectively). Discrimination was better using shape and form (shape + centroid size) of the fore wings than of the hind wings. The wing form parameters were found to differ significantly in shape and centroid size among the three analyzed subspecies. Finally, it may be concluded that landmark-based geometric morphometrics could be a powerful tool to characterize the Algerian honey bees.
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Ajanović, Zurifa, Uzeir Ajanović, Lejla Dervišević, et al. "A Geometric Morphometrics Approach for Sex Estimation Based on the Orbital Region of Human Skulls from Bosnian Population." Scanning 2023 (April 14, 2023): 1–9. http://dx.doi.org/10.1155/2023/2223138.
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Background. Understanding the anatomy and morphological variability of the orbital region is of great importance in clinical practice, forensic medicine, and biological anthropology. Several methods are used to estimate sex based on the skeleton or parts of the skeleton: classic methods and the geometric morphometric method. The objective of this research was to analyse sex estimation of the orbital region on a sample of skulls from a Bosnian population using the geometric morphometric method. Materials and Methods. The research was conducted on three-dimensional models of 211 human adult skulls (139 males and 72 females) from the Osteological Collection at the Faculty of Medicine in Sarajevo. The skulls were recorded using a laser scanner to obtain skull 3D models. We marked 12 landmarks on each model to analyse sexual dimorphism. Landmarks were marked using the program Landmark Editor. After marking the landmarks, we used the MorphoJ program to analyse the morphological variability between male and female orbital regions. Results. After Procrustes superimposition, generating a covariant matrix, and introducing sex as a variable for classification, a discriminant functional analysis (DFA) was applied which determined the estimation for males with 86.33% accuracy and for females with 88.89% based on the form of the orbital region. The results of regression analysis showed that the size of the orbital region has a statistically significant effect on its shape’s sexual dimorphism. After excluding the influence of size and providing DFA, we concluded that sex estimation was possible with 82.01% accuracy for males and 80.55% accuracy for females based on the shape of the orbital region in the examined sample. Conclusion. Sex estimation based on the orbital region was possible with more than 80% accuracy for both sexes, which is a high percentage of correct estimation. Therefore, we recommend using the orbital region of the skull for sex estimation.
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Rohlf, F. James. "Shape Statistics: Procrustes Superimpositions and Tangent Spaces." Journal of Classification 16, no. 2 (1999): 197–223. http://dx.doi.org/10.1007/s003579900054.
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Prado-Silva, Arlete, Lorena Andrade Nunes, Rogério Marcos de Oliveira Alves, Paulo Luiz Souza Carneiro, and Ana Maria Waldschmidt. "Variation of fore wing shape in Melipona mandacaia Smith, 1863 (Hymenoptera, Meliponini) along its geographic range." Journal of Hymenoptera Research 48 (March 1, 2016): 85–94. https://doi.org/10.3897/JHR.48.6619.
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Melipona mandacaia is a stingless bee species responsible for the pollination of many native plants in Brazil, South America. In spite of its ecological and economic importance, natural populations of M. mandacaia have been depleted because of deforestation. In order to evaluate the interpopulation morphometric structure of remaining populations, we carried out geometric morphometric studies based on fore wing shape in this native bee species. The grouping analysis by UPGMA revealed three distinct clusters and significant differences in fore wing size were observed (p<0.001) among populations. The three groups were also reflected in the first two principal components explaining about 60% of the total variation. These results indicate differentiation among populations, which can be regarded as unique management units. Therefore, efforts should be directed to the conservation of local populations of M. mandacaia to avoid the negative impacts of loss in pollination over plant species and environmental services.
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Brudnicki, Andrzej, Tereza Petrova, Ivana Dubovska, Anne Marie Kuijpers-Jagtman, Yijin Ren, and Piotr S. Fudalej. "Alveolar Bone Grafting in Unilateral Cleft Lip and Palate: Impact of Timing on Palatal Shape." Journal of Clinical Medicine 12, no. 24 (2023): 7519. http://dx.doi.org/10.3390/jcm12247519.
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Alveolar bone grafting (ABG) is a critical surgical intervention in patients with a cleft of the alveolus, aimed at reconstructing the alveolar ridge to facilitate proper eruption, periodontal support, and alignment of adjacent permanent teeth. The optimal timing for ABG remains debated, with late secondary ABG between the ages of 9 and 11 being widely adopted. This study compared the palatal shapes of 28 children at a mean age of 9.5 years (SD = 0.7) who underwent early secondary ABG at a mean age of 2.1 years (SD = 0.6) or 33 children at a mean age of 10.8 years (SD = 1.5) who underwent late secondary ABG at a mean age of 8.6 years (SD = 1.3) to 60 non-cleft controls at a mean age of 8.6 years (SD = 1.2). The palatal shapes were captured with 239 landmarks digitized on the palate on a digital model. Utilizing geometric morphometric methods, i.e., generalized Procrustes superimpositions, principal component analysis, and permutation tests, we assessed the impact of ABG timing on palatal morphology. The first five principal components (PCs) explained 64.1% of the total shape variability: PC1 = 26.1%; PC2 = 12%; PC3 = 11.9%; PC4 = 7.8%; and PC5 = 6.4%. The Procrustes distance between both cleft groups and the control group was more than twice as large as the Procrustes distance between the early ABG and late ABG groups. Nonetheless, all intergroup differences were statistically significant. Our findings suggest that early ABG has a limited negative effect on palatal shape, providing comparable outcomes to late ABG. The study highlights the potential suitability of early ABG, challenging conventional practices and encouraging further exploration into its long-term effects on maxillary growth.
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Ahn, Mi So, Sang Min Shin, Te-Ju Wu, et al. "Correlation between the cross-sectional morphology of the mandible and the three-dimensional facial skeletal pattern: A structural equation modeling approach." Angle Orthodontist 89, no. 1 (2018): 78–86. http://dx.doi.org/10.2319/122117-879.1.
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ABSTRACT Objective: To clarify the relationship between the cross-sectional morphology of the mandible and vertical, transverse, and anteroposterior facial skeletal patterns using statistical shape analysis and structural equation modeling (SEM). Materials and Methods: We used 150 cone beam computed tomography (CBCT) images to obtain three-dimensional (3D) facial landmarks and cross-sectional images of the mandible. The morphology of the inner and outer cortices of the mandible was analyzed using statistical shape analysis, including generalized Procrustes analysis and principal component analysis (PCA). Factor analysis was performed to determine factors pertaining to the skeletal measurements and shape variations for the inner and outer cortices, following which a structural equation model was constructed. Results: Using factor analysis, characteristics of the vertical, transverse, and anteroposterior facial skeletal patterns were determined. PCA of the cross-sectional morphology of the mandible revealed 70% of the cumulative proportion by PC1 and PC2 after generalized Procrustes superimpositions. SEM showed complex relationships between the facial skeletal patterns and variations in the cross-sectional morphology of the mandibular cortices. The influence of the transverse factors on the outer cortex as a latent variable was relatively significant (P = .057). However, the influence of the vertical factors on the outer and inner cortices was not significant. Conclusions: The transverse skeletal pattern is associated with the morphology of the outer cortex of the mandible.
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Peres-Neto, Pedro R., and Donald A. Jackson. "How well do multivariate data sets match? The advantages of a Procrustean superimposition approach over the Mantel test." Oecologia 129, no. 2 (2001): 169–78. http://dx.doi.org/10.1007/s004420100720.
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Vetrova, Valentina P., Alexey P. Barchenkov, and Nadezhda V. Sinelnikova. "Comparative analysis of shape variation in the cone scales of Larix dahurica and L. cajanderi (Pinaceae)." Vestnik Tomskogo gosudarstvennogo universiteta. Biologiya, no. 53 (2021): 47–67. http://dx.doi.org/10.17223/19988591/53/3.
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Geometric morphometric analysis of shape variation in the cone scales of two closely related larch species, Larix dahurica Laws. (=Larix gmelinii (Rupr.) Rupr) and L. cajanderi Mayr, was carried out. The data on the taxonomy and distribution of L. dahurica and L. cajanderi are contradictory. The taxonomic status of L. cajanderi has been confirmed by the genetic and morphological studies performed in Russia and based on considerable evidence, but the species has not been recognized internationally, being considered as a synonym of Larix gmelinii var. gmelinii. In the systematics of larch, morphological characters of the generative organs are mainly used as diagnostic markers, among the most important being the shape variation of the cone scales. The aim of this study was to test geometric morphometrics as a tool for analyzing differentiation of L. dahurica and L. cajanderi in the shape of their cone scales. Characterization of shape variations in cone scales using geometric morphometric methods consists in digitizing points along an outline of scales followed by analysis of partial warps, describing individual differences in coordinates of the outline points. We studied the populations of L. dahurica from Evenkia and the Trans-Baikal region and six L. cajanderi populations from Yakutia and Magadan Oblast. In each population, we analyzed samples of 100-150 cones collected from 20-30 trees. Scales taken from the middle part of the cones were scanned using an Epson Perfection V500 Photo. On the scanned images, outline points were placed with a TPSDig program (Rolf, 2010), using angular algorithm (Oreshkova et al., 2015). The data were processed and analyzed using Integrated Morphometrics Programs (IMP) software (http://www.canisius.edu/~sheets/ morphsoft.html, Sheets, 2001), following the guidelines on geometric morphometrics in biology (Pavlinov, Mikeshina, 2002; Zelditch et al., 2004). Initial coordinates of the scale landmarks were aligned with the mean structure for L. dahurica and L. cajanderi cone scales using Procrustes superimposition in the CoordGen6 program. PCA based on covariances of partial warp scores was applied to reveal directions of variation in the shape of the cone scales. The relative deformations of the cone scales (PCA scores) were used as shape variables for statistical comparisons of these two larch species with canonical discriminant analysis. Morphotypes of the cone scales were distinguished in L. dahurica populations by pairwise comparison of samples from trees in the TwoGroup6h program using Bootstrap resampling-based Goodall’s F-test (Sheets, 2001). Samples from the trees in which the cone scales differed significantly (p < 0.01) were considered to belong to different morphotypes. Morphotypes distinguished in L. dahurica populations were compared with the morphotypes that we had previously determined in L. cajanderi populations. The composition and the frequency of occurrence of morphotypes were used to determine phenotypic distances between populations (Zhivotovskii, 1991). Multidimensional scaling matrix of the phenotypic distances was applied for ordination of larch populations. In this research, we revealed differentiation of L. dahurica and L. cajanderi using geometric morphometric analysis of the shape variation of cone scales. The results of PCA of partial warp scores exposed four principal components, which account for 90% of total explained variance in the shape of the cone scales in the two larch species. Graphical representations of these shape transformations in the vector form characterized directions of shape variability in scales corresponding to the maximum and minimum values of four principal components (See Fig. 2). PCA-ordination of the larch populations revealed some difference in the shape variation of the cone scales in L. dahurica and L. cajanderi (See Fig. 3). The results of canonical discriminant analysis of relative deformations of scales showed differentiation of the populations of the two larch species (See Fig. 4). Eleven morphotypes were identified in L. dahurica cones from Evenkia and nine morphotypes in the Ingoda population, three of the morphotypes being common for both populations (See Fig. 5). The shape of L. dahurica cone scales varied from spatulate to oval and their apical margins from weakly sinuate to distinctly sinuate. The Trans-Baikal population was dominated by scales with obtuse (truncate) and rounded apexes. The obtained morphotypes were compared with 25 cone scale morphotypes previously distinguished in the Yakut and the Magadan L. cajanderi populations (See Fig. 3). Four similar morphotypes of cone scales were revealed in the North-Yeniseisk population of L. dahurica and the Yakut populations of L. cajanderi. The differences between them in the populations of the two larch species were nonsignificant (p > 0.01). All morphotypes of cone scales from the Ingoda population of L. dahurica differed significantly from L. cajanderi cone scale morphotypes. The results of multidimensional scaling phenotypic distance matrix calculated based on the similarity of morphotypes of L. dahurica and L. cajanderi populations were consistent with the results of their differentiation based on relative deformations of scales obtained using canonical discriminant analysis (See Fig. 4 and Fig. 7). In spite of the differences in the shape of the cone scales between the North-Yeniseisk and the Trans-Baikal populations of L. dahurica, they both differed from L. cajanderi populations. Thus, phenotypic analysis confirmed differentiation of these two larch species. Despite the similarities between a number of morphotypes, the Yakut L. cajanderi populations were differentiated from L. dahurica populations. Significant differences were noted between intraspecific groups: between L. cajanderi populations from Okhotsk-Kolyma Upland and Yakutia and between L. dahurica populations from Evenkia and the Trans-Baikal region (See Fig. 4). The similarities between species and intraspecific differences may be attributed to the ongoing processes of hybridization and species formation in the region where the ranges of the larches overlap with the ranges of L. czekanowskii Szafer and L. dahurica×L. cajanderi hybrids. Geometric morphometrics can be used as an effective tool for analyzing differentiation of L. dahurica and L. cajanderi in the shape of their cone scales.
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Klingenberg, Christian Peter. "How Exactly Did the Nose Get That Long? A Critical Rethinking of the Pinocchio Effect and How Shape Changes Relate to Landmarks." Evolutionary Biology, October 30, 2020. http://dx.doi.org/10.1007/s11692-020-09520-y.
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Abstract The Pinocchio effect has long been discussed in the literature on geometric morphometrics. It denotes the observation that Procrustes superimposition tends to distribute shape changes over many landmarks, even though a different superimposition may exist for the same landmark configurations that concentrates changes in just one or a few landmarks. This is widely seen as a flaw of Procrustes methods. Visualizations illustrating the Pinocchio effect use a comparison of the same pair of shapes superimposed in two different ways: in a resistant-fit superimposition that concentrates the shape difference in just one or a few landmarks, and in Procrustes superimposition, which distributes differences over most or all landmarks. Because these superimpositions differ only in the non-shape aspects of size, position and orientation, they are equivalent from the perspective of shape analysis. Simulation studies of the Pinocchio effect usually generate data, either single pairs or larger samples of landmark configurations, in a particular superimposition so that differences occur mostly or exclusively at just one or a few landmarks, but no steps are taken to remove variation from size, position and orientation. When these configurations are then compared with Procrustes-superimposed data, differences appear and are attributed to the Pinocchio effect. Overall, it is ironic that all manifestations of the Pinocchio effect in one way or another rely on differences in the non-shape properties of position and orientation. Rigorous thinking about shape variation and careful choice of visualization methods can prevent confusion over this issue.
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Rhoda, Daniel, Marion Segall, Olivier Larouche, Kory Evans, and Kenneth D. Angielczyk. "Local Superimpositions Facilitate Morphometric Analysis of Complex Articulating Structures." Integrative and Comparative Biology, April 27, 2021. http://dx.doi.org/10.1093/icb/icab031.
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Synopsis Articulating structures, such as the vertebrate skeleton or the segmented arthropod exoskeleton, comprise a majority of the morphological diversity across the eukaryotic tree of life. Quantifying the form of articulating structures is therefore imperative for a fuller understanding of the factors influencing biological form. A wealth of freely available 3D data capturing this morphological diversity is stored in online repositories such as Morphosource, but the geometric morphometric analysis of an articulating structure is impeded by arbitrary differences in the resting positions of its individual articulating elements. In complex articulating structures, where the angles between articulating elements cannot be standardized, landmarks on articulating elements must be Procrustes superimposed independently (locally) and then recombined to quantify variation in the entire articulating structure simultaneously. Here, we discuss recent advances in local superimposition techniques, namely the “matched local superimpositions” approach, which incorporates anatomically accurate relative sizes, positions, and orientations of locally-superimposed landmarks, enabling clearer biological interpretation. We also use simulations to evaluate the consequences of choice of superimposition approach. Our results show that local superimpositions will isolate shape variation within locally-superimposed landmark subsets by sacrificing size and positional variation. They may also create morphometric “modules” when there are none by increasing integration within the locally-superimposed subsets; however, this effect is no greater than the spurious between-module integration created when superimposing landmark subsets (i.e., articulating elements) together. Taken together, our results show that local superimposition techniques differ from conventional Procrustes superimpositions in predictable ways. Finally, we use empirical datasets of the skulls of wrasses and colubriform snakes to highlight the promise of local superimpositions and their utility. Complex articulating structures must be studied, and the only current solution to do so is local superimpositions.
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Ana, Bucchi, and Del Bove Antonietta. "Accuracy in estimating missing shape data using linear regression." July 14, 2022. https://doi.org/10.5281/zenodo.6833471.
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Landmark set for 222 skulls (143 chileans and 79 italians). Data has 14 fixed landamrks and 95 surface sliding semilandmarks which were located in the face bones. The landmark set was subject to Procrustes superimposition to standardize for location, orientation and scale.
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Marugán-Lobón, Jesus. "Median-based resistant methods in the current framework of Geometric Morphometrics." Spanish Journal of Palaeontology, March 5, 2025. https://doi.org/10.7203/sjp.29737.
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Landmark-based geometric morphometric (GM) methods have become a standard in shape analysis. Superimposition of landmark constellations, referenced to the mean, is performed using the least squares criterion under the consensus framework of Generalized Procrustes Analysis (GPA). While effective, especially when combined with multivariate statistics, this approach also has limitations. Specifically, if there is localized variation (if a few landmarks are significantly displaced in relation to the others), the method homogenizes variation to perform an optimal fit that can spread variation randomly, yielding unrealistic results. This limitation has long been recognized and discussed in the literature—especially paleontological—proposing methods based on repeated medians that help checking for such localized variation in landmark constellations. However, the broad establishment of GPA has led to their neglect, potentially compromising interpretations in studies of allometry, integration, and modularity. Two real life examples, one biological (spiders) and one paleobiological (pterosaur skulls), are used to illustrate what "localized variation" means and the effect it can have on the structure of Procrustes shape data, and consequently, on further statistical analyses. The intended message is that median-based resistant methods for landmark superimposition should be re-implemented
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Zelditch, Miriam Leah, and Donald L. Swiderski. "Effects of Procrustes Superimposition and Semilandmark Sliding on Modularity and Integration: An Investigation Using Simulations of Biological Data." Evolutionary Biology, March 29, 2023. http://dx.doi.org/10.1007/s11692-023-09600-9.
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Zelditch, Miriam Leah, and Donald L. Swiderski. "Correction: Effects of Procrustes Superimposition and Semilandmark Sliding on Modularity and Integration: An Investigation Using Simulations of Biological Data." Evolutionary Biology, June 3, 2024. http://dx.doi.org/10.1007/s11692-024-09637-4.
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Abed, Fouzia, Benabdellah Bachir-Bouiadjra, Lahouari Dahloum, Abdulmojeed Yakubu, Ahmed Haddad, and Abdelkader Homrani. "Procruste analysis of forewing shape in two endemic honeybee subspecies Apis mellifera intermissa and A. m. sahariensis from the Northwest of Algeria." Biodiversitas Journal of Biological Diversity 22, no. 1 (2020). http://dx.doi.org/10.13057/biodiv/d220121.
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Abstract. Abed F, Bachir-Bouiadjra B, Dahloum L, Yakubu A, Haddad A, Homrani A. 2021. Procruste analysis of forewing shape in two endemic honeybee subspecies Apis mellifera intermissa and A. m. sahariensis from the Northwest of Algeria. Biodiversitas 22: 154-164. Honey bees play an important role as pollinators of many crops. Thus they are collectively considered as a veritable economic source. The present study was undertaken to describe variation in the right forewing geometry in two Algerian honeybee subspecies Apis mellifera intermissa and Apis mellifera sahariensis using landmark-based geometric morphometrics. A total of 1286 honeybees were sampled from 12 provinces in the northwest of Algeria. The forewing geometry was evaluated using 20 homologous landmarks by applying Procrustes superimposition analysis. The top four principal components accounted for only 41.1% of wing shape variation between the two subspecies. There was a significant difference in wing shape between the two subspecies (Mahalanobis distance = 1.0626 ; P<0.001), whereas their wing size seemed similar (P>0.05). Regarding the allometric effect, the percentage of variation in wing shape explained by size changes was relatively small, with 1.28% and 4.37% for A. m. intermissa and A.m sahariensis, respectively. The cross-validation procedure correctly classified 68.3% of specimens into their original groups. PERMANOVA test revealed significant differences in the right forewing shape among all geographic areas studied (P<0.001). The results clearly showed that the landmark-based geometric approach applied to forewings venation is a powerful and reliable tool in the discrimination of native honey bee subspecies and should be considered in local honey bee biodiversity improvement and conservation initiatives.
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Hennocq, Quentin, Olivier Lienhard, Dipesh Rao, et al. "Next Generation Phenotyping and Synthetic Faces in Coffin Siris Syndrome." Clinical Genetics, December 26, 2024. https://doi.org/10.1111/cge.14682.
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ABSTRACTDiagnostic wandering and delayed management are major issues in rare diseases. Here, we report a new Next‐Generation Phenotyping (NGP) model for diagnosing Coffin Siris syndrome (CSS) on clinical photographs among controls and distinguish the different genotypes. This retrospective and prospective study, conducted from 1998 to 2023, included frontal and lateral pictures of confirmed CSS. After automatic placement of landmarks, geometric features extraction using procrustes superimposition, and textural features using a gray‐level co‐occurrence matrix (GLCM), we incorporated age, gender, and ethnicity and used XGboost (eXtreme Gradient Boosting) for classification. An independent validation set of confirmed CSS cases from centers in Bangalore (India) and Tbilissi (Georgia) was used. We then tested for differences between genotype groups. Finally, we introduced a new approach for generating synthetic faces of children with CSS. The training set included over 196 photographs from our center, corresponding to 58 patients (29 controls, 29 CSS). We distinguished CSS from controls in the independent validation group with an accuracy of 90.0% (73.5%–97.9%, p = 0.001). We found no facial shape difference between the different genotypes.
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Roussos, Petros, Anastasia Mitsea, Demetrios Halazonetis, and Iosif Sifakakis. "Craniofacial shape in patients with beta thalassaemia: a geometric morphometric analysis." Scientific Reports 11, no. 1 (2021). http://dx.doi.org/10.1038/s41598-020-80234-z.
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AbstractThe shape of the craniofacial complex of patients with beta thalassaemia was evaluated using geometric morphometrics on lateral cephalometric radiographs and was compared with matched controls. The beta thalassaemia group consisted of 40 patients (16 females, 24 males, mean age 33.4). Each patient was matched by age and gender to two controls (32 females, 48 males, mean age 33.1). The 120 lateral cephalometric radiographs were digitized and traced with 15 curves, 10 landmarks and 117 sliding semi-landmarks. These landmarks were subjected to Procrustes superimposition and principal component analysis in order to describe shape variability of the cranial base, maxilla and mandible, as well as of the entire craniofacial complex for each sex. The first 4 principal components accounted for 50% of the total sample’s variability. The beta thalassaemia group was significantly different in overall shape to the control group for both sexes. Similar findings were noted for the maxilla, the mandible and the cranial base. The main differences were related to smaller mandibular body for the thalassaemia group, midface protrusion and decrease in posterior face height. The shape of the craniofacial complex in these patients is prone to be more convex and hyperdivergent.
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Gupta, Anmol, Joshua Meaike, Anthony Pagano, Daniella Franco Curcio, Peter Som, and Jeffrey T. Laitman. "Use of Axial CT Scans to Assess Early Postnatal Development of the Internal Nares: a Test of Reliability." FASEB Journal 30, S1 (2016). http://dx.doi.org/10.1096/fasebj.30.1_supplement.780.7.
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Human newborns are exclusively nasal breathers due to an anatomical configuration of the aerodigestive tract, similar to those of non‐human primates. Thus, choanal stenosis and other upper airway obstructions may be serious conditions among infants. Morphometric studies lack standardized methods to investigate size, proportion and position of the internal nares in relation to the skull. This study tests the hypothesis that 3D coordinates for landmarks and craniometric points taken on axial CT scans can be reliably used to assess choanal aperture and craniofacial anatomy via 3D geometric morphometrics. We used the computer program Osirix® to identify 16 landmarks on 23 axial scans of monkey skulls (Macaca mulatta) as a model to test accuracy. Two observers underwent four training sessions to plot the landmarks on specimens apart from the study sample. Each observer performed three assessments per specimen and no specimen was evaluated twice in the same day. We assessed landmark accuracy using Generalized Procrustes Analysis by optimal superimposition, scaling by Centroid Size and measured the procrustes distances to interpret data. The obtained interobserver errors were higher than 5%, which indicates that 3D landmark coordinates obtained from axial slices generate considerable interobserver variation and low reproducibility of measurements between structures or bone regions situated in different planes. There was no significant difference in interobserver accuracy in identifying standard craniometric points or regional landmarks assessed by ANOVA. This study indicates that collection of 3D coordinates from axial slices to assess the complex morphology of the choanae and how it changes with growth and development involves intrinsic errors of measurement that must be addressed and controlled when performing geometric morphometric analysis. Next step of this project is using volume rendered 3D CT scans and obtain coordinates for the same landmarks to determine interobserver variability, assess accuracy, and validate reproducibility.Support or Funding InformationIcahn School of Medicine's Summer Student Investigator Program Award/CNPq ‐ Brazilian National Counsel of Technological Development
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Tepedino, Michele, Michele Laurenziello, Laura Guida, et al. "Morphometric analysis of sella turcica in growing patients: an observational study on shape and dimensions in different sagittal craniofacial patterns." Scientific Reports 9, no. 1 (2019). http://dx.doi.org/10.1038/s41598-019-55916-y.
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AbstractThe aim of this study was to evaluate the differences in sella dimensions and shape between growing patients with Class I, Class II, and Class III skeletal malocclusions, evaluated through morphometric analysis. Seventy-eight subjects aged between 9 and 13 years were selected and assigned to either the Class I, Class II, or Class III groups according to the measured ANB angle (the angle between the Nasion, skeletal A-point and skeletal B-point). Six landmarks were digitised to outline the shape of the sella turcica. Linear measurements of the sella length and depth were also performed. Procrustes superimposition, principal component analysis, and canonical variate analysis were used to evaluate the differences in sella shape between the three groups. A one-way MANOVA and Tukey’s or Games-Howell tests were used to evaluate the presence of differences in sella dimensions between the three groups, gender, and age. The canonical variate analysis revealed a statistically significant difference in sella shape between the Class I and the Class II groups, mostly explained by the CV1 axis and related to the posterior clinoidal process and the floor of the sella. No differences were found regarding linear measurements, except between subjects with different age. These differences in sella shape, that are present in the earlier developmental stages, could be used as a predictor of facial growth, but further studies are needed.
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Burgio, G. Baylac M. Heyer E. Montagutelli X. "Genetic analysis of skull shape variation and morphological integration in the mouse using interspecific recombinant congenic strains between C57BL/6 and mice of the mus spretus species." May 28, 2009. https://doi.org/10.1111/j.1558-5646.2009.00737.x.
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To assess the genetic basis of the skull shape variation and morphological integration in mice, we have used a tool based on the cross between the distantly related mouse species Mus spretus (SEG/Pas strain) and the laboratory strain C57BL/6 called interspecific recombinant congenic strains (IRCSs). The genome of each IRCS consists on average of 1.3% of SEG/Pas derived sequences, located on multiple chromosomes as small-sized, DNA segments. Quantitative trait loci (QTL) on the skull shape, separated into dorsal and ventral sides, were analyzed in 17 IRCSs by a Procrustes superimposition method using 3D landmarks. The shapes of 16 strains differed significantly from C57BL/6. Discrepancy in the QTLs effects was found between the dorsal side and the anterior region of the ventral side due to a differential effect of the SEG/Pas alleles on the skull shape. A comprehensive analysis of all allelic combinations of the BCG-66H strain showed strong epistatic interactions between SEG/Pas segment acting on both skull sides. Epistatic pleiotropy and covariation between sides were dependent in SEG/Pas alleles direction and contributed to the strong morphological integration between sides. Introduction of Mus spretus alleles in a C57BL/6 background induced strong morphological changes mostly in SEG/Pas alleles direction and provided evidence for high level of morphological integration.