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1
Kingsmill, V. J., C. M. Gray, D. R. Moles, and A. Boyde. "Cortical Vascular Canals in Human Mandible and Other Bones." Journal of Dental Research 86, no. 4 (April 2007): 368–72. http://dx.doi.org/10.1177/154405910708600413.
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The human mandible is highly mineralized. We hypothesized that this is related to the local vascularity of the bone. This could not be examined directly, but, as a surrogate, intracortical vascular canal spaces of the human mandible were studied so that we could determine possible relationships with age, gender, location, dental status, and tissue mineralization. Canal numbers, area, and volume fraction were calculated from quantitative backscattered electron images of human mandibles aged 16–96 years. Data were compared with calvaria, maxilla, lumbar vertebra, femoral neck, and iliac crest. In the mandible, the buccal aspect of the midline was the most porous, the canals being larger and more numerous. The cortical porosity in the posterior of partially dentate mandibles was significantly greater than that of either dentate or edentate mandibles, and there was a significant increase in the size of canals in the mandible with increasing age. Female mandibles had more porous cortices. No relationship was found between cortical porosity and the degree of bone mineralization.
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Curcio, Ricardo, Guilherme Luis Perin, Israel Chilvarquer, Maria Lucia Borri, and Sergio Ajzen. "Use of models in surgical predictability of oral rehabilitations." Acta Cirurgica Brasileira 22, no. 5 (October 2007): 387–95. http://dx.doi.org/10.1590/s0102-86502007000500011.
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PURPOSE: To evaluate the rehabilitation of edentulous mandibles with osseous integrated implants in immediate loading, using models in reverse planning. METHODS: A prospective study was performed on 14 patients with a total of 56 implants placed. It was proposed a technique for the rehabilitation of edentulous mandible with osseous integrated implants of immediate loading, using anatomical replicas derived from computerized tomography scan linked to the rapid prototyping technique of stereolithography in reverse planning, elaborating the definitive fixed prosthesis, with rigid union of the implants on the same day. The patients' mandible models were divided in two groups. In the first one, there were patients with edentulous mandible models and with models elaborated after exodontics procedures (Group 1). In the second (Group 2), patients with dentulous mandible models, which allow an evaluation of difficulty in the surgery. RESULTS: The proposed technique using anatomical models for the personalization of mandibles in immediate loading had 100% of less difficulty in the adaptation of the surgery guide while the dentulous models had 83,3% of more difficulty. CONCLUSION: The proposed technique using the mandible models in the rehabilitation of mandibles is feasible.
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Ingawale, Shirish M., Deepak G. Krishnan, and Tarun Goswami. "Validation of Experimental and Finite Element Biomechanical Evaluation of Human Cadaveric Mandibles." Lubricants 10, no. 8 (July 25, 2022): 169. http://dx.doi.org/10.3390/lubricants10080169.
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Background: Biomechanical analysis of human mandible is important not only to understand mechanical behavior and structural properties, but also to diagnose and develop treatment options for mandibular disorders. Therefore, the objective of this research was to generate analytical and experimental data on mandibles, construct custom 3D models, and compare the analytically derived maximum strains with strain gage data in five areas of interest for each mandible. Methods: We investigated the surface strains in the cadaveric human mandibles under different configurations of cyclic compressive loads in an experimental setting and compared these experimental strain data with results derived from computational finite element analysis (FEA), accurately replicating the experiments. Strains on the surface of each mandible were measured with strain gauges, and subsequently a subject-specific finite element (FE) volume mesh was generated from computed tomography (CT) scans of each mandible. Strain patterns of each mandible were derived from the FEA simulating the experimental setup and matched with the experimental data. Findings: Analysis of experimental data showed that strain as measured at the condylar locations was significantly different from those at other locations on the mandible, and that the sex and age of the subject did not have a significant correlation with the strain. Comparing the FE numerical predictions with the experimental data, we found a good statistical correlation and statistical agreement between in-vitro measurements and FE results. Interpretation: The study demonstrates that our methodology of generating subject-specific FE models is a valid and accurate, non-invasive method to evaluate the complex biomechanical behavior of human mandibles.
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Sugiyo, Paul, and Heriyanti Amalia Kusuma. "Obturator Definitive Mandibula Post Hemimandibulectomy Sinistra." Majalah Kedokteran Gigi Indonesia 19, no. 2 (December 31, 2012): 158. http://dx.doi.org/10.22146/majkedgiind.15541.
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Latar Belakang. Operasi bedah pemotongan mandibula pada kasus tumor jinak maupun tumor ganas dapat menyebabkan deviasi mandibula. Tindakan perawatan bedah tergantung pada lokasi dan perluasan tumor mandibula, tindakan perawatan bedah tersebut meliputi bedah marginal, segmental, hemimandibulectomy, dan total mandibulectomy. Tujuan. Makalah ini menjelaskan tentang perawatan rehabilitasi dengan obturator definitive mandibula. Para klinisi harus menunggu masa penyembuhan yang sempurna sebelum disarankan untuk dibuatkan onturator definitive mandibula. Sejak awal penyembuhan diperlukan intervensi prostodontis untuk mencegah deviasi mandibula. Protesa ini membantu pergerakan mandibula secara normal tanpa terjadi penyimpangan pada fungsi bicara dan pengunyahan. Laporan Kasus. Pada bulan Maret 2012, pasien laki-laki, berumur 46 tahun datang ke RSGM Bagian Prostodonsia atas rujukan dari RS. Dr. Sardjito Bagian Bedah Mulut setelah dilakukan operasi tumor ameloblastoma mandibula sinistra (post hemimandibulectomy mandibula sinistra) dengan pemasangan plat rekonstruksi tiga bulan sebelumnya untuk dibuatkan obturator definitive mandibula. Pasien mengeluh bibir bawah sebelah kiri sering tergigit, fungsi bicara, fungsi pengunyahan, dan penampilannya terganggu. Hasil. Setelah dilakukan perawatan dengan memakai obturator definitive mandibula dalam kurun waktu 8 bulan, hingga saat ini hasil perawatan ini dapat mengembalikan fungsi bicara, fungsi pengunyahan, dan fungsi estetik sehingga pasien merasa lebih nyaman dan percaya diri. Kesimpulan. Deviasi mandibula setelah operasi hemimandibulectomy diatasi dengan bedah rekonstruksi menggunakan plat rekonstruksi, kemudian segera setelah penyembuhan perlu melibatkan prostodontis untuk pemasangan obturator definitive mandibula. Background. Surgical restion of the mandible due to presence of benign or malignant tumor is the common cause of the mandibular deviation. Depending upon the location and extent of the tumor in the mandible, various surgical treatment modalities like marginal, segmental, hemimandibulectomy, or total mandibulectomy. Purpose. This study was to deteminated of rehabilitation treatment by mandible definitive obturator. The clinicians must wait for extensive period of the time for completion of healing before considering the definitive prosthesis. During this initial healing period prosthodontic intervention is required for preventing the mandibular deviation. This case report describes management of a patient who has undergone a reconstructed hemimandibulectomy with mandible definitive obturator. The prosthesis help patient moving the mandible normally without deviation during functions like speech, mastication, and aesthetic. Case Report. On March 2012, a 46 years old man was referred from Dr. Sardjito Hospital Oral Surgery Department to Department of Prosthodontics RSGM Faculty of Dentistry Gadjah Mada University Yogyakarta, for prosthetic rehabilitation following a hemimandibulectomy sinintra reconstructed with plate reconstruction three months ago. Patient felt speech function, masticatory function, and impaired performance, lower lip frequently bitten. Results. After treated while 8 months till now by mandible definitive obturator, patient felt more comfortable and confident with recovery function of speech, mastication, and aesthetic. Conclusion. The deviation of mandible after hemimandibulectomy was reconstructed by reconstruction plate surgery. During this initial healing period early prosthodontic intervention by mandible definitive obturator.
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Hao, LingYu, Jia Li, YaWen Tian, and JunHua Wu. "Changes in the MicroRNA Profile of the Mandible of Ovariectomized Mice." Cellular Physiology and Biochemistry 38, no. 4 (2016): 1267–87. http://dx.doi.org/10.1159/000443074.
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Background/Aims: In postmenopausal women, a decrease in bone mineral density (BMD) at the hip and spine is associated with an increased risk of tooth loss, possibly caused by the loss of the alveolar bone. The present study explored the effect of the ovariectomy (OVX) of mice on the miRNA expression profile of their bones. Methods: Micro-CT and histological analysis were performed on mice following OVX or sham-operation using the right mandibles. The left mandibles were used for microarray and quantitative RT-PCR to explore the change in their miRNA expression profile. The differentially expressed miRNAs (DEmiRs) of the OVX and sham-operated mice were analyzed by constructing the miRNA-mRNA-function complex network. We then also analyzed the different roles of the regulation of miRNAs in the mandible and femur by combining public data from GEO. Results: OVX could lead to a significant decrease in the BMD in the mandible. A total of 53 DEmiRs including, 18 up-regulated and 35 down-regulated miRNAs, were identified. The analysis of the miRNA-mRNA-pathway complex network suggested that miR-17-5p and miRNA-297a-5p were potential biomarkers in the development of mandibles of OVX mice. A comparison of the analysis data on the mandible and femur showed that the transforming growth factor-β signaling pathway was specifically regulated in the mandible, whereas the Wnt signaling pathway was specifically regulated in the femur. Moreover, miR-17-5p and miR-133a-3p showed different expression tendencies in the mandible and in the femur after OVX. Conclusion: This study provides an integrated function analysis of miRNA in mandibles after OVX and of miR-17-5p and miR-133a-3p as potential biomarkers. Moreover, the mechanism in mandibles may not be comparable with that in femurs with estrogen deficiency.
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Ichiishi, Wataru, Shinpei Shimada, Takashi Motobayashi, and Hiroaki Abe. "Completely engaged three-dimensional mandibular gear-like structures in the adult horned beetles: reconsideration of bark-carving behaviors (Coleoptera, Scarabaeidae, Dynastinae)." ZooKeys 813 (January 7, 2019): 89–110. http://dx.doi.org/10.3897/zookeys.813.29236.
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Adult horned beetles (Coleoptera, Scarabaeidae, Dynastinae) such as Trypoxylusdichotomus (Linnaeus, 1771) exhibit bark-carving behaviors to feed on tree sap, in part by using small projections of the clypeus. However, in the present experiments, adult horned beetles (T.dichotomus and Dynasteshercules (Linnaeus, 1758)) used their mandibles and not the projections of the clypeus to carve bark. Our findings show the presence of completely engaged mandibular interlocking, gear-like surface structures in molar areas that guide mandible opening and closure, and lead to completely synchronous movements of adult horned beetle mandibles. Three-dimensional shapes of these mandibular gear-like structures are complex and remained in contact after the death of a beetle. Moreover, adult horned beetles often performed bark-carving behaviors using only the mandible of one side, suggesting that the primary role of the mandibular gear-like structure is to prevent breakage of the mandible by transmitting load from one mandible to the other. Among the 22 Dynastinae and 16 other beetle species examined (not Dynastinae), the gear-like structure was found in all the Dynastinae species and in no other species.
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Dutta, Abir, Kaushik Mukherjee, Venkata Sundeep Seesala, Kaushik Dutta, Ranjan Rashmi Paul, Santanu Dhara, and Sanjay Gupta. "Load transfer across a mandible during a mastication cycle: The effects of odontogenic tumour." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 234, no. 5 (February 5, 2020): 486–95. http://dx.doi.org/10.1177/0954411920904618.
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The extent to which load transfer in a diseased mandible with odontogenic tumour might influence the potential risk of pathological fracture has scarcely been investigated. The study sought to investigate the quantitative deviations in load transfer across healthy and cancer-affected (diseased) mandibles having odontogenic tumours. The effect of size of the tumours (small: 9 mm diameter, large: 19 mm diameter), and variation in bone mechanical (elastic) properties of the mandible on load transfer in cancer-affected mandibles during a mastication cycle have been investigated. Based on patient-specific computed tomography–scan datasets, detailed three-dimensional finite element models of healthy and diseased mandibles were developed. High stresses of 25–30 MPa and strains ∼700 µε were observed in the healthy mandible during the right molar bite. However, marginal deviations were observed in principal stress distributions in the diseased mandibles with small- and large-sized tumours, as compared to the healthy mandible. Maximum principal strains of ∼1474 µε were found in the body region adjacent to the symphysis region for small-sized tumour. Whereas for large-sized tumour, maximum strains of ∼2700 µε were observed in the right buccal regions. Reduction in Young’s modulus due to different stages of odontogenic tumours had a localised effect on the principal stress distributions, but triggered an abrupt increase in the principal tensile strains. It appears that there is a potential risk of pathological fracture for large-sized odontogenic tumour, owing to high tensile stresses and strains.
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de Amorim Rocha, Layla Louise, Matheus Francisco Barros Rodrigues, Rodrigo da Franca Acioly, Daniel do Carmo Carvalho, and Cristofe Coelho Lopes da Rocha. "Augmentation of the Atrophic Mandible with a Block Corticomedullary Graft." Case Reports in Dentistry 2020 (June 29, 2020): 1–5. http://dx.doi.org/10.1155/2020/6837519.
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The gradual loss of the dental alveolus leads to bone resorption, which may cause atrophy of the maxilla and mandible. One of the most complex procedures in reconstructive surgery is the rehabilitation of patients with atrophic mandibles. Herein, we present a clinical case study of atrophic mandible augmentation with grafts obtained from the iliac crest. The use of reconstruction plates may represent a feasible mechanism for treatment as well as fracture prevention. Mandible augmentation performed by grafting the donor site of the iliac crest showed satisfactory results and resolution of the aesthetic and functional impairments.
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Ndiaye M R, Mar N B, Yacouba Garba K, and Ndoye J M N. "Mental foramen of Human Mandible: Morphometric Study." International Journal of Anatomy and Research 9, no. 4 (December 5, 2021): 8109–15. http://dx.doi.org/10.16965/ijar.2021.164.
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Aim: The aim of our study was to perform a morphometric analysis of the mental foramen in senegalese context. Material and method: The study was performed on thirty-nine dry mandibles of adult humans. On these mandibles, the number of mental foramen present and their shape were noted on inspection. The situation of the foramen in relation to the lower teeth was studied according to a methodology already described. The following measurements were made: the distance between the foramen and the other landmarks of the mandible (symphysis, basilar border, posterior border), vertical and horizontal diameters. Results: The number of mental foramina were 39 on the right and 40 on the left: one mandible presented a double foramen on the left. The oval shape was predominant. The most frequent situation was below the second premolar on both sides. The mean distance between the foramen and the mandibular symphysis was 25mm on both sides. The distance between the foramen and the basilar border of the mandible was on average 13mm on the right and 14mm on the left. The distance between the foramen and the posterior border of the mandible was on average 72mm on the right and 73mm on the left. The average vertical diameter was 33mm on the right and 32mm on the left, and the average horizontal diameter was 4mm on both sides. Conclusion: Mental foramen is a constant anatomical structure, found on all the mandibles studied. The results can be superimposed on those described in the majority of studies carried out on the mental foramen. Key words: Mental Foramen, Mandible Anatomy, Morphometry.
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Wheeler, Mark M. "Discriminating Between Adult Mandibles of Oryzaephilus surinamensis and Oryzaephilus mercator Using Setal Brush Length." Journal of AOAC INTERNATIONAL 76, no. 4 (July 1, 1993): 941–43. http://dx.doi.org/10.1093/jaoac/76.4.941.
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Abstract The setal brush was identified as a diagnostic characteristic which can be used to distinguish between the mandibles of adult Oryzaephilus surinamensis and O. mercator. The right and left setal brushes of 50 specimens from each species were measured. Statistical analysis showed that the mean brush lengths of the 2 species were significantly different (ρ = 0.0001). A demarcation value was established to distinguish between the mandibles. By using this value it is possible to reliably classify the mandibles of O. surinamensis and O. mercator. A mandible with setal brush >0.0296 mm would be classified as O. mercator, a mandible with a setal brush <0.0296 mm would be classified as O. surinamensis.
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Ichim, I., M. Swain, and J. A. Kieser. "Mandibular Biomechanics and Development of the Human Chin." Journal of Dental Research 85, no. 7 (July 2006): 638–42. http://dx.doi.org/10.1177/154405910608500711.
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The development of the chin, a feature unique to humans, suggests a close functional linkage between jaw biomechanics and symphyseal architecture. The present study tests the hypothesis that the presence of a chin changes strain patterns in the loaded mandible. Using an anatomically correct 3-D model of a dentate mandible derived from a CT scan image, we analyzed strain patterns during incisal and molar biting. We then constructed a second mandible, without a chin, by ‘defeaturing’ the first model. Strain patterns of the second model were then compared and contrasted to the first. Our main finding was that chinned and non-chinned mandibles follow closely concordant patterns of strain distribution. The results suggest that the development of the human chin is unrelated to the demands placed on the mandible during function.
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Kadel, Muna, Bishwo P. Sedhain, and Prakash MS Dangol. "Morphometric analysis of mental foramen in human dry mandibles of nepalese population." Asian Journal of Medical Sciences 7, no. 6 (October 31, 2016): 82–86. http://dx.doi.org/10.3126/ajms.v7i6.15697.
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Background: Mental foramina are located bilaterally in the antero-lateral aspect of the body of mandible. It transmits mental nerve, and vessels. The location, shape, size, direction and number of mental foramen in human mandibles are subject of variation. Aims and Objective: To establish the location, shape, size, direction and incidence of mental foramen (MF) in dry human mandibles of Nepalese population.Materials and Methods: One hundred dry human mandibles of unknown age and sex were selected randomly. Shape, size, position of MF with respect to tooth and other anatomical landmark were determined. Student paired t-test was used for specific statistical analysis.Results: In most cases (61%), the MF was oval in shape & situated below the apex of second premolar (58% on right side and 69% on left side). Various parameters investigated were, the horizontal distance between (1) base of mandible and MF was 12.24 mm on right and 12.26mm on the left, (2) alveolar margin and MF was 13.95 mm on right &13.75 mm on left (3) symphysis menti of mandible and MF was 26.71 mm on right and 26.49 mm on left, (4) posterior border of mandible and MF was 65.34 mm on right and 65.68mm on left.Conclusion: By the knowledge of position, shape, size, direction and distance of the mental foramen from various landmarks and the presence of the accessory foramen may be of much use to dental surgeons.Asian Journal of Medical Sciences Vol.7(5) 2016 82-86
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Weihmann, Tom, Thomas Kleinteich, Stanislav Gorb, and Benjamin Wipfler. "Functional morphology of the mandibular apparatus in the cockroach Periplaneta americana (Blattodea: Blattidae) - a model species for omnivore insects." Arthropod Systematics & Phylogeny 73, no. 3 (December 14, 2015): 477–88. http://dx.doi.org/10.3897/asp.73.e31833.
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We examine the functional morphology of the mandibular apparatus, including its driving muscles, of the generalist insect Periplaneta americana using a combination of μ-computed tomography and geometrical modelling. Geometrical modelling was used to determine the changes of the mean fibre angle and length in the mandibular adductor muscle over the physiological range of mandible opening. The roughly scissor-like mandibles are aligned along the dorso-ventral axis of the head and are characterised by sharp interdigitating distal teeth, as well as a small proximal molar region. The mechanical advantage of the mandibles, i.e. the ratio between inner and outer levers, ranges between 0.37 to 0.47 depending on the considered incisivus. The mandibular abductor muscle is comprised of eight muscle fibre bundles, which are defined by distinct attachment positions on the sail-like apodeme protruding from the medio-lateral basis of the mandibles into the head lumen. Compared to carnivorous, herbivorous, or xylophagous insects, the relative volumes of the mandibular abductor and adductor muscle are small. Dependent on the mandible opening angle, the mean fibre angle of the adductor muscle ranges from 34° to 21°, while mean fibre length changes from 1.24 mm (closed mandible) to 1.93 mm at maximum mandible opening. Many of the specific morphological features found in the chewing apparatus of P. americana, such as the presence of a mola in combination with distal incisivi, small relative muscle size and the intermediate fibre angle can be understood as adaptations to its omnivorous life style.
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Mártha I., Krisztina, Cristina Bica, Blanka Kész, and Bernadette Kerekes Máthé. "A canalis mandibulae lefutásának vizsgálata különböző vertikális arctípusokban." Orvosi Hetilap 158, no. 46 (November 2017): 1841–47. http://dx.doi.org/10.1556/650.2017.30864.
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Abstract: Introduction: The precise knowledge of the position of canalis mandibulae and foramen mandibulae is important for surgical and endodontic interventions on the mandible. Aim: The aim of the study is to examine the position of these anatomical landmarks in different vertical facial types. Method: In the panorama radiograph of 26 normodivergent, 26 hypodivergent and 28 hyperdivergent arthritis (total of 1360 measurements) we measured the distance between the canalis mandibulae and interdental septums, the apex of the lateral teeth, the mandibular base, the goniac angle, and the steepness of the canal and the distance the foramen mandibulae to the anterior and posterior margin of the ramus. Results: ANOVA and t-test statistical analysis showed that the foramen mandibulae is farer from the posterior margin of the ramus in hipodivergent facial types, in hyperdivergent facial types the canalis mandibulae was closer to the root apex of posterior teeth and in hypodivergent types to the base of the mandible. In normal and hyperdivergent individuals, the canalis mandibulae runs steeper and in the course of running it is increasingly distanced from the tangent to the base of the mandible. Conclusion: The position of the canalis mandibulae and the foramen mandibulae showed significant differences in the different vertical facial types. Orv Hetil. 2017; 158(46): 1841–1847.
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Romaniuk, A. "Functional and Phylogenetic Aspect in Modularity of Palearctic Mustelids (Carnivora, Mustelidae) Mandible." Vestnik Zoologii 52, no. 2 (April 1, 2018): 165–76. http://dx.doi.org/10.2478/vzoo-2018-0018.
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Abstract Geometric morphometrics was used to investigate morphological integration and modularity in mustelid mandible. A set of 16 two-dimensional landmarks was digitized on the mandibles of 14 extant species of Palearctic Mustelidae (genera Enhydra, Gulo, Meles, Lutra, Martes, Mustela). The original data size-corrected data and phylogenetically independent contrasts (PICs) were analyzed. Several hypotheses were tested: two and three-modules with the masseteric fossa included in corpus or ramus of the mandible. As a result, the two-module hypothesis (subdivision into the alveolar region and the ascending ramus) with masseteric fossa included in corpus for all sets of data was supported. A clear modularity in mustelid mandible is seen at interspecific level, whereas there was large within species covariation between mandibular corpus and ramus. The allometry correction reduces estimates of covariation for the mustelid mandibles. Due to the analysis of PICs the shape changes with maximum evolutionary covariation were found: elongated, sloped backward ramus and thick corpus.
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Russett, Shawn, Paul Major, Jason Carey, Roger Toogood, and Pierre Boulanger. "An Experimental Method for Stereolithic Mandible Fabrication and Image Preparation." Open Biomedical Engineering Journal 1, no. 1 (July 17, 2007): 4–10. http://dx.doi.org/10.2174/1874120700701010004.
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Reproduction of anatomical structures by rapid prototyping has proven to be a valid adjunct for craniofacial surgery, providing alternative methods to produce prostheses and development of surgical guides. The aim of this study was to introduce a methodology to fabricate asymmetric human mandibles by rapid prototyping to be used in future studies for evaluating mandibular symmetries. Stereolithic models of human mandibles were produced with varying amounts of asymmetry in the condylar neck, ramus and body of the mandible by means of rapid prototyping. A method for production of the synthetic mandibles was defined. Model preparation, landmark description and development of the experimental model were described. A series of synthetic mandibles ranging in asymmetry were accurately produced from a scanned human mandible. A method for creating the asymmetries, fabricating, coating and landmarking the synthetic mandibles was formulated. A description for designing a reproducible experimental model for image acquisition was also outlined. Production of synthetic mandibles by stereolithic modeling is a viable method for creating skeletal experimental models with known amounts of asymmetry.
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Vaghela, Bhadreshkumar P., Boski Gupta, and Sudarshan Gupta. "Topography of the location of mental foramen in dried edentulous human mandible and its clinical implication." Indian Journal of Clinical Anatomy and Physiology 8, no. 4 (March 15, 2022): 320–24. http://dx.doi.org/10.18231/j.ijcap.2021.069.
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The mental foramen is an oval or round opening on external surface of mandible and transmits mental nerve and vessels. Mostly located at apex of second mandibular premolar or between the apices of premolars. The study was commenced on 60 dried edentulous mandibles with the aim to determine location of mental foramen(MF) with reference to surrounding anatomical landmarks. By measuring its distance from midline (symphysis menti), posterior border of ramus of mandible, lower border of mandible. Length of lower border (Base) of mandible was also measured. In present study most common shape of mental foramen was round (70%). The mean distances of MF from midline are 24.36mm on right side and 24.15mm left side. From posterior border of ramus are 64.45mm on right side and 64.15mm on left side. From base of mandible are 12.29mm on right side and 12.48mm on left side. Length of base mandible (midline to angle of mandible) is 83.27mm right side and 83.12mm left side. Ratio of distance from symphysis menti to MF and length of base of mandible are same on both sides that are 0.29. There is statistically significant positive correlation between distance from symphysis menti to MF and length of base of mandible.The MF plays a very important role in treatment planning and its location needs to be considered prior to placement of dental-implants, regional anesthesia, osteotomy-surgeries and during complete denture-fabrication in order to avoid MN injury and related complications.
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B, Gayathrie, Suganya S, and Murugesan K. "Complete denture as a myofunctional therapeutic appliance to guide the patient into centric relation –A clinical report." JOURNAL OF CLINICAL PROSTHODONTICS AND IMPLANTOLOGY 2, no. 2 (December 30, 2020): 19–22. http://dx.doi.org/10.55995/j-cpi.2020011.
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One of the most difficult tasks to accomplish in complete denture treatment is retruding the mandible to obtain the centric relation (CR) record 1-8. This can occur due to the absence of synchronization in groups of opposing muscles when the patients are asked to close in the retruded position. Several methods have been designated for helping the edentulous patient to retrude their mandibles into CR 2-9. The tongue can be utilized to help the edentulous patients to record CR 2,4,9-14. When the tip of the tongue is turned back toward the soft palate, it exerts a muscular pull on the mandible in a backward direction to the desired position. Many appliances that guide the mandible to the centric relation position have been utilized in the past. However, most of these appliances can compromise speech and oral hygiene. This article describes a simple procedure that enables the edentulous patient to retrude the mandible to its CR position and to reduce the hazards of protruding the mandible from its retruded position during closing the mouth to CR.
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Smajilagić, Amer, and Faruk Dilberović. "Clinical and anatomical study of the human mental foramen." Bosnian Journal of Basic Medical Sciences 4, no. 3 (August 20, 2004): 15–23. http://dx.doi.org/10.17305/bjbms.2004.3376.
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The great diffusion of the surgical techniques in jaws surgery and the progress of the radiological imagining procedures expressed many interest in clinical anatomy of the mental foramen (MF). The study goal was to determine the precise location of the MF and the surrounding anatomical landmarks. Measurements of the MF position relative to the surgical landmarks and related posterior teeth were made on 20 dry mandibles with complete dentition and intact alveolar bridge obtained from the Institute of Anatomy, School of Medicine, University in Sarajevo. The measurements were made by anthropometric methods on the booth sides of the mandible, and compared with measurement made on the orthopantomogram radiographs of the same mandibles. The most common position of the MF was in line with the longitudinal axis of the second premolar. In the vertical plane on the skulls the MF lays in the midpoint of the distance between the lower border of the mandible and the alveolar margin, however on the orthopantomogram MF appeared slightly bellow the midpoint. In the horizontal plane it lays approximately one third of the distance between the mandibular symphysis and the posterior border of the ramus of the mandible measurement from A-P projection and one quarter of that distance measurement from the profile projection. There were no significant differences between distances MF from posterior border of the ramus of the mandible measurement from A-P and profile projection and the one obtained on orthopantomogram and their ratio is constant value determine das 1,065. The MF was on average 25 mm lateral to the mandibular skeletal midline and symmetrical, and symmetry was preserved on the orthopantomogram. The measurement showed significant differences in distances of M from superior border mandible measurement on dry mandible and orthopantomogram radiographs while distance bellow the MF was not significantly different. The constant values of MF distance to the posterior border of the ramus of the mandible measured as 1,065 and the distance to the medial skeletal line of 2,11 made it possible to also determine average angle of 43 degrees stream of the cor-pus of the mandible behind MF. These values in combination with ratios of MF to the different anatomic landmarks designated as relative horizontal and relative vertical position, would be of importance not only from anatomical but also from practical point of view for estimation of alveolar bridge resorption and preoperative analysis in orthognat postresection or implant surgery in the mandible.
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Suman, Parineeta, Sabita Singh, and Raj Kishore Mahato. "Mental foramen and accessory mental foramen: a dry human mandibles study in South Indian population." National Journal of Clinical Anatomy 7, no. 04 (October 2018): 182–91. http://dx.doi.org/10.1055/s-0040-1701734.
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Abstract Introduction and aim: Mandible usually has a bilateral oval or circular mental foramen [MF] situated on the anterolateral aspect of the body of mandible. Variations of the MF are often encountered ranging from difference in incidence, shape, size, position and supernumerary [accessory MF] to even complete absence. So, the aim of the present study was to evaluate the incidence and the anatomical features of the mental foramen and the accessory mental foramen. Materials & method: 61 dry human mandibles of unknown sex were examined. Size and distance of mental foramen and accessory mental foramen from symphysis menti [Mandibular midline], inferior border of the mandible, posterior border of ramus and superior border of body of mandible were measured using vernier calliper and statistically analyzed by mean and standard deviation. Results: Bilateral mental foramina [MF] were present in all 61 [100%] mandibles. Out of 122 mental foramina [MF], 86 [70.5%] were round and 36 [29.5%] were oval in shape. Approximately half [47.54%] of MF were present below the apex of 2nd premolar tooth. MF was located approximately half way between alveolar crest and mandibular body. Bilateral AMF were present in 1.64% mandibles. All 5 AMFs were round in shape. AMF was separated from MF by a median distance of 2mm. Conclusion: The knowledge about incidence and variability in position of mental foramen and accessory mental foramen is important in order to avoid nerve damage in connection with surgical procedure and to achieve complete effect of anaesthesia after mental nerve block
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Goto, N., K. Watanabe, H. Umezawa, H. Yazawa, and S. Kuramasu. "Morphometrical observations on the mandible of five strains of rabbits and strain identification using mandible measurements." Laboratory Animals 21, no. 3 (July 1, 1987): 188–94. http://dx.doi.org/10.1258/002367787781268738.
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In order to clarify the relationships between five strains of rabbits and to identify the strains, principal component and discriminant analyses were carried out using 12 mandibular measurements of three inbred strains (JW-NIBS/Y (JW/Y), NW-NIBS/Y (NW/Y) and Dutch-NIBS/Y (D/Y)) and two outbred strains (JW-NIBS (JW) and NW-NIBS (NW)) which were maintained at the Nippon Institute for Biological Science. The results obtained were as follows. (1) Principal component analysis revealed that in the males the mandible of JW was the largest but with considerable variation. D/Y was the smallest of all strains examined. The mandibles of NW and NW/Y were similar to the JW mandibles but had a shape which was shorter and higher. In the females the mandible of NW was the largest of all strains and, as in the males, D/Y was the smallest and JW varied markedly. (2) Discriminant analysis showed the probability of erroneous discrimination to be 14·8% (34/229) when the inbred and outbred strains were combined. In both sexes erroneous discrimination mostly occurred between NW and NW/Y, which have the same origin, and between JW and NW, which have a common ancestor. However, when the inbreds and outbreds were identified separately by discriminant analysis, the probability of erroneous discrimination was low in both cases (4·5% (5/112) and 7·7% (9/117) respectively). These results indicate that strain differences are found in the size and shape of rabbit mandibles and that mandible analysis is effective for strain identification of laboratory rabbits.
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Nehriasari, Indria, and Maria G. Widiastuti. "Hemimandibulektomi dengan Rekonstruksi Mandibula dan Fiksasi Intermaksila sebagai Penatalaksanaan Ameloblastoma Mandibula Sinistra." Majalah Kedokteran Gigi Indonesia 19, no. 2 (December 31, 2012): 145. http://dx.doi.org/10.22146/majkedgiind.15538.
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Latar belakang. Ameloblastoma adalah tumor odontogenik yang jarang terjadi. Walaupun jinak tetapi bersifat merusak dan mempunyai tingkat kekambuhan yang tinggi. Hemimandibulektomy adalah salah satu tindakan yang dipilih jika lesi patologis telah melibatkan processus coronoideus dan condyle walaupun efek dari tindakan tersebut adalah terjadinya defek wajah dan deviasi mandibula. Tujuan. Melaporkan tindakan hemimandibulektomy dengan rekonstruksi bridging plate dan traksi intermaksila pada ameloblastoma mandibula sebelah kiri yang dilakukan untuk mengurangi deviasi dan defek wajah. Kasus dan perawatan. Laki-laki umur 46 tahun datang ke klinik bedah mulut dan maksilofacial RS Dr Sardjito Yogyakarta dengan keluhan utama adanya pembengkakan pada sisi kiri rahang bawah di area pipi. Keadaan tersebut dirasakan sejak 4 tahun yang lalu, tidak sakit, keras, warna sesuai dengan jaringan sekitar. Diagnosa yang ditegakkan Ameloblastoma mandibula. Perawatan dari kasus ini adalah hemimandibulektomy dengan rekonstruksi bridging plate dengan anestesi umum. Enam minggu dengan kawat dan 3 bulan dengan traksi elastic digunakan untuk mengurangi deviasi mandibula setelah tulang rahang direseksi. Kesimpulan. Hemimandibulektomi dilakukan untuk mengambil lesi patologi secara radikal untuk mencegah rekurensi. Bridging plate digunakan sebagai tindakan rekontruksi mandibula. Traksi intermaksila merupakan salah satu cara yang bisa digunakan untuk mengurangi deviasi mandibula setelah hemimandibulektomy. Background. Ameloblastoma is an odontogenic tumor which rarely happened. Although it is benign, it can be destructive and has a high recurrency rate. Hemimandibulectomy is one kind of treatments which can be choosed if pathologic fracture has involved coronoid processus and condyle, eventhough its effect can cause mandible deviation and facial defect. Purpose. Reported a hemimandibulectomy with bridging plate reconstruction and intermaxillary function on the left mandible ameloblastoma intended to reduced the deviation of the mandible. Case and threatment. Fourty-six years old man came to the oral and maxillofacial surgery clinic at Dr. Sardjito Hospital Yogyakarta, with a main sign of swelling at the left side of lower jaw on buccal region, it was emerged approximately 4 years ago, painless, hard on palpation, colour as normal. Treatment of this case was hemimandibulectomy and reconstruction with bridging plate under general anaesthesia. Six weeks wiring and 3 months elastic traction was used to decrease mandible deviation as an intermaxillary fixation. Partial removable denture used to complete the treatment. Conclusion. Treatment at this case is aimed to eliminate all tumor with hemimandibulectomy and bridging plate is placed to reconstruct the mandible. The use of the intermaxillary elastic traction as an intermaxillary fixation until get the normal occlusion could be one alternative treatment to reduced mandible deviation after hemimandibulectomy.
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Chen, Zhen-Yi, Yuying Hsu, and Chung-Ping Lin. "Allometry and Fighting Behaviour of a Dimorphic Stag Beetle Cyclommatus mniszechi (Coleoptera: Lucanidae)." Insects 11, no. 2 (January 23, 2020): 81. http://dx.doi.org/10.3390/insects11020081.
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Male stag beetles (Coleoptera: Lucanidae) use their mandibles as weapons to compete for resources and reproduction. Mandible size in stag beetles can be associated with different behaviours and the outcome of male contests. We investigated the allometric relationship between mandible and body size in males of the stag beetle Cyclommatus mniszechi to uncover distinct morphs. The results divided male C. mniszechi into majors and minors with the switch point of mandible length at 14.01 mm. The allometric slope of mandibles was positive for both morphs but was steeper for the minors. We also characterised the fighting behaviour of the different morphs in size-matched contests using sequential analyses. Males matched each other’s behaviour in contests with many physical contacts, no injury and a progression from low towards high aggression and rare de-escalation. Major and minor males employed the same behavioural elements in contests, but major males were more likely to escalate directly into more aggressive phases and minor males tended to stay within phases. This finding suggests that major males may compete more aggressively than minor males in contests.
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Hsu, Kun-Jung, Hui-Na Lee, and Chun-Ming Chen. "Morphological Investigation of Mandibular Lingula: A Literature Review." Journal of Personalized Medicine 12, no. 6 (June 20, 2022): 1015. http://dx.doi.org/10.3390/jpm12061015.
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Purpose: The purpose of the study was to review the literature on the shape of the mandibular lingula. Methods: English articles published from 1970 to 2021 in databases (PubMed, Web of Science, and Embase) were selected. Articles meeting the search strategy were evaluated based on the eligibility criteria (participants aged 18 years and over). Dry mandibles and cone beam computed tomography (CBCT) images were used as research materials. The shapes of mandibular lingula were classified as triangular, truncated, nodular, and assimilated. Results: Based on the eligibility criteria, 10 articles (six with dry mandibles and four with CBCT images) were selected for full-text reading and detailed examination. In the dry mandible group, triangular, truncated, nodular, and assimilated lingula were observed on 446, 398, 232, and 69 sides, respectively. In the CBCT group, nodular, truncated, triangular, and assimilated lingula were observed on 892, 517, 267, and 88 sides, respectively. Therefore, the most common lingula types in the dry mandible and CBCT groups were different. The assimilated type was the least common in both groups. Conclusion: In the dry mandible group, the most common lingula type was triangular, followed by truncated, nodular, and assimilated types. In the CBCT group, the most common lingula type was nodular, followed by truncated, triangular, and assimilated types. There were no significant differences in lingula types between the left and right sides of the mandible.
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Sidorkewicj, Nora S., and Emma B. Casanave. "Morphological characterization and sex-related differences of the mandible of the armadillos Chaetophractus vellerosus and Zaedyus pichiy (Xenarthra, Dasypodidae), with consideration of dietary aspects." Iheringia. Série Zoologia 103, no. 2 (June 2013): 153–62. http://dx.doi.org/10.1590/s0073-47212013000200011.
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The morphological characteristics of the mandible of adult Chaetophractus vellerosus (Gray, 1865) and Zaedyus pichiy (Desmarest, 1804) were studied to establish its generalized design and to identify inter- and intra- (sexual) specific differences. Morphological descriptions were complemented with the application of univariate and multivariate (analysis of correlation matrices, PCA, discriminant analysis) techniques. The mandible of both species is very similar, and is characterized by elevated condyle, well developed angular process, distinct coronoid process, tooth row which extends to the rear end of the angle between body and ramus, and unfused but firm symphysis. Although both armadillos are omnivorous, a more slender configuration of the jaw in Z. pichiy could be indicative of a better adaptation of its masticatory apparatus to insectivory. The PCA showed an almost total segregation of both species on PC1 (47.7% of the total variance), with C. vellerosus being associated to mandibles taller and with wider body and ramus. Zaedyus pichiy was characterized by heavy loadings of length parameters on PC2 (22.6% of the variance). A small degree of sexual dimorphism was found, with size-based differences in C. vellerosus (larger mandibles in females) and shape-based differences in Z. pichiy (taller mandibles in males, longer ones in females). Correlations between variables were higher in males of both species, indicating a more stable shape of the mandible than in females. The selected parameters to discriminate sexes were the body length of the mandible in C. vellerosus (correct classification: ca. 86% in males, 81% in females), and the height of the mandible at the level of the last tooth in Z. pichiy (near 85% of right assignment in both sexes). The inclusion of a new variable (body length) in the latter species improved the classification of the females to 100%. Teeth are typically 10 in C. vellerosus and 9 in Z. pichiy, but aberrancies in this basic number, such as unilateral or bilateral extra or fewer teeth, are common.
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Honomichl, Klaus. "Muskelrezeptoren an der Mandibel von Insekten Muscle Receptors at the Mandible of Insects." Entomologia Generalis 31, no. 2 (April 1, 2008): 173–91. http://dx.doi.org/10.1127/entom.gen/31/2008/173.
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Karmali, Nand Kishor, Keshav Krishna, and Rajesh R. "Morphological and Morphometric Evaluation of Mandibular Coronoid Process, Condylar Process and Mandibular Ramus in Jharkhand and Bihar Population." International Journal of Research and Review 9, no. 2 (February 4, 2022): 10–16. http://dx.doi.org/10.52403/ijrr.20220203.
Full textAbstract:
Background: Coronoid process of mandible gives attachment to temporalis and masseter muscles. The shape and size of coronoid process varies widely due to influence of many factors. Its shape has been described as triangular, hook shaped and rounded in various studies. Mandibular Condyle, is the part of the mandible that articulates with the temporal bones articular fossa and its appearance is influenced by various factors. The superior border of the mandible's ramus is formed by the mandibular notch and its contour is influenced by shape of the Coronoid process and the Mandibular condyle. Knowledge of these morphological variations is of great help to anthropologists, maxillofacial surgeons and forensic experts. Aim: Aim of present study is the morphological differences in Coronoid process, Condylar process, and Mandibular Notch in adult dry human mandibles in Jharkhand and Bihar. Material and method: 100 dry adult Mandible of known sex from the Department of Anatomy, Phulo-Jhano Medical College Dumka, Jharkhand and other medical colleges of Jharkhand and Bihar were studied. Shape of the coronoid process was visually assessed. Length of the coronoid process and mandibular process were measured by employing standardized method, using digital Vernier calliper. Results: The triangular (120) shape of the coronoid process was the most common among the 200 sides, with 72 (60%) on the right side and 48 (40%) on the left. The second was beak-shaped (68), with 36 (52.9 percent) on the right side and 32 (47 percent) on the left side, followed by the round shape (12), of which 7 (58.4%) were on the right side and 5 (41.6%) on the left side. Mean length of right and left side of coronoid process among male was 17.79 ±0.88 mm and 17.51±0.83mm respectively, while in females these measurements were 16.59±0.97mm and 16.33±0.68 mm respectively. Mean length of right and left side of mandibular condyle among male was 12.9 ± 2.13mm and 10.88±2.01mm respectively, while in females this value was 11.8± 1.67mm and 11.21± 1.75mm respectively. Average distance from the head of the mandible to the base of the mandible on right and left sides were64.22±5.77 mm and 64.05 ± 5.92 mm respectively. Similarly values for distance from the base of the mandible to mandibular notch were 46.32±7.21mm and46.24±8.49mm respectively and values for distance from the anterior border to the posterior border of the ramus of mandible were 30.48 ± 2.36mmand 30.31±2.32mm on right and left side respectively. Conclusion: Triangular shape of coronoid process was most common type seen in Jharkhand and Bihar population. This finding is similar to many other such studies. There was statistically significant difference between length of coronoid process and mandibular condyle of male and female. All these findings are of immense importance to anthropologists, maxillofacial reconstructive surgeons and forensic experts. Keywords: Morphology, Morphometry, Coronoid, Condyloid, sigmoid notch, Mandible.
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Booher, Douglas B., and Philipp O. Hoenle. "A new species group of Strumigenys (Hymenoptera, Formicidae) from Ecuador, with a description of its mandible morphology." ZooKeys 1036 (May 5, 2021): 1–19. http://dx.doi.org/10.3897/zookeys.1036.62034.
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Strumigenys is one of the most diverse ant genera in the world and arguably the most morphologically diverse, exhibiting an exceptional range of mandible shape and function. A new species, Strumigenys ayerstheysp. nov., discovered in the Chocó region of Ecuador is described. With two morphological characters, this species is shown to be a morphologically unique outlier among Strumigenys globally, having predominately smooth and shining cuticle surface sculpturing and long trap-jaw mandibles. Using µCT scans, we produced 3D images of the worker ant and static images to examine and compare mandible articular morphologies with most morphologically similar members of the mandibularis species group. Cuticular, pilosity, and articular mandible morphological differences supports placing the new species in its own new species group.
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Lestari, Sri, and Rini Widyaningrum. "Hubungan fraksi area trabekula anterior mandibula dengan kepadatan tulang lumbar spine untuk deteksi dini osteoporosis." Majalah Kedokteran Gigi Indonesia 3, no. 1 (October 31, 2017): 43. http://dx.doi.org/10.22146/majkedgiind.13207.
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The relationship of anterior mandible trabecular area with bone mass density of lumbar spine for early detection of osteoporosis. Bone mineral density is an indicator of osteoporosis, including the bone mineral density of lumbar spine. The decrease of lumbar spine bone mass density will cause an alteration in another site, including the mandibular. The aim of this research is to determine the predictor of lumbar spine bone mineral density using trabecular bone image of anterior mandible on periapical radiographs. The research was conducted by extracting the area fraction at mandible trabecular bone using digital periapical radiograph from 25 subjects. Canny edge detection was used in digital image processing for each radiograph. The regions of interest were selected from the image obtained by canny edge detection, so that the area fraction could be measured. A linier regression test was applied to determine a relationship between the area fractions of mandible trabecular bone with the bone mineral density of lumbar spine. The result of linear regression test showed that the area fraction of mandible trabecular bone had a moderate negative correlation with bone mass density of lumbar spine (α = 0.046; R = -0.403). The direction of the correlation was negative (b = -0.145). The area fraction of mandible trabecular bone on periapical radiographs could be used as the predictor for bone mass density of lumbar spine.ABSTRAKKepadatan tulang merupakan indikator osteoporosis, salah satu diantaranya adalah kepadatan tulang pada lumbar spine. Penurunan kepadatan tulang pada lumbar spine mempengaruhi kondisi tulang lain, termasuk tulang rahang bawah (mandibula). Tujuan penelitian ini adalah untuk menentukan prediktor densitas mineral tulang menggunakan citra radiograf periapikal tulang trabekula pada regio anterior rahang bawah. Penelitian dilakukan dengan ekstraksi fraksi area tulang trabekula mandibula yang tercitrakan pada radiograf periapikal digital dari 25 subjek. Pengolahan citra digital pada radiograf periapikal dilakukan dengan menggunakan metode deteksi tepi canny terhadap masing-masing citra radiograf. Region of Interest diseleksi dari citra hasil deteksi canny, sehingga dapat dilakukan pengukuran fraksi area. Uji regresi linier dilakukan untuk mengetahui hubungan antara nilai fraksi area trabekula mandibula dengan tingkat kepadatan tulang pada lumbar spine. Hasil uji regresi linier menunjukkan bahwa nilai fraksi area trabekula mandibula berkorelasi negatif dengan kepadatan tulang dengan kekuatan sedang (α = 0,046; R = -0,403). Adapun arah korelasi antara nilai fraksi area trabekula mandibula dengan kepadatan tulang adalah negatif (b = -0,145). Fraksi area tulang trabekula pada citra radiograf periapikal dapat digunakan sebagai prediktor kepadatan tulang pada lumbar spine.
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Neprokina, Anastasiya V., Elena D. Lutsay, and Marina A. Vinidictova. "Anatomical features of the human fetus mandible." Science and Innovations in Medicine 7, no. 1 (January 15, 2021): 4–8. http://dx.doi.org/10.35693/2500-1388-2022-7-1-4-8.
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Aim to obtain new data on the anatomy of the mandible of a human fetus aged 1923 weeks.
Material and methods. The object of the study was 40 mandibles of human fetuses of both sexes aged from 19 to 23 weeks. The morphological method (macromicroscopic preparation; the method of saw cuts according to N.I. Pirogov; production of serial histotopograms) and the method of ultrasound scanning by the device VOLUSONS 10, RAB 6 RS sensor in 2D mode and in the "Skeleton" program (3D mode) were used.
Results. In fetuses aged 1923 weeks the mandible represents a paired bone connected in the center by a symphysis. According to the shape of the body, it is possible to select wide and short, long and narrow mandibles in a ratio of 2 to 1, respectively 67% and 33%. The length of the alveolar arch is 52.4 5.6 mm (with a range of 45.360.2 mm), the angular width is 23.4 1.7 mm (with a range of 19.027.8 mm). The height of the branch at the cutting level was equal to 6.2 1.4 mm (with a range of 3.69.0 mm). On the anterior surface of the body, one chin opening is determined on both sides, at an average distance of 16.4 mm from the angle of the mandible and at a height of 2.2 mm. On the inner surface of the branch, the opening of the mandible is determined, located at a distance of 3.6 1.1 mm from the angle, 3.2 0.9 mm from the anterior edge of the branch, 4.1 1.2 mm from the posterior edge of the branch. In the second trimester of pregnancy, dental alveoli are determined in the mandibular dental arch of the fetus. Significant sex differences were found for the angle of the mandible (p 0.05). In girls, the angle was 141.1 10.1, in boys 129.5 9.4.
Conclusion. The mandible of the fetus at the age of 1923 weeks is formed and has fetal characteristics. During this period, no significant bilateral differences were revealed, sexual differences start to form.
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Suzuki, Kei, Hiroyuki Nakano, Kazuya Inoue, Yoichiro Nakajima, Sho Mizobuchi, Michi Omori, Nahoko Kato-Kogoe, Katsuaki Mishima, and Takaaki Ueno. "Examination of new parameters for sex determination of mandible using Japanese computer tomography data." Dentomaxillofacial Radiology 49, no. 5 (July 2020): 20190282. http://dx.doi.org/10.1259/dmfr.20190282.
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Objective: In the field of forensic science, sex discrimination of skeletons is an important identification item for personal identification. The individual sex discrimination method using skeletons includes a determination method using measurement values and a macroscopic form observation method. Both methods have advantage and disadvantage. In this study, we used the homologous model technique and principal component (PC) analysis to determine gender difference from morphology of the mandible. Methods and materials: 45 patients (23 males and 22 females) of CT imaging for tooth extraction from January 2018 to March 2019 at department of oral surgery, Osaka Medical College. The mean age was 43.1 ± 14.6. Patients with less than 14 remaining teeth were excluded because the number of remaining teeth may affect the shape of the mandible. 3D images were constructed, and 20 landmarks plotting on the 3D model surfaces. We generated template models of the mandible consisting of approximately 8434 polygons. The template model automatically fitted into the individually scanned point cloud of the mandible by minimising external and internal energy functions. As described above, the mandibles were constructed for each sample by using the Homologous Body Modeling software (HBM, Digital Human Technology, Inc.) and the mHBM-Rugle (Medic Engineering Corporation). The mandibles were analysed using the PCA. Results: The contribution of the most important PC was found to be 27.2%. 12 PCs explained over 75% of the total variance. That is, it was able to express 75% or more of the mandible expression with 12 PCs. A significant difference between male and female was observed in the first PCs (Wilcoxon test, p < 0.05). Visualising the result of the first PC showed that the mandibular branch of male was larger than that of female, and the mandible angle was overhanging outside. Conclusion: This method is a combination of the determination method using the previous measurement values and the determination using macroscopic observation, and is considered to be innovative method.
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Taylor, Nathan, Casey T. Clark, Nicole Misarti, and Lara Horstmann. "Determining sex of adult Pacific walruses from mandible measurements." Journal of Mammalogy 101, no. 4 (June 20, 2020): 941–50. http://dx.doi.org/10.1093/jmammal/gyaa051.
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Abstract Pacific walruses (Odobenus rosmarus divergens) play a vital role in Arctic marine ecosystems and the subsistence lifestyle of Alaska Native communities. Museum collections contain numerous archaeological and historic walrus specimens that have proven useful in a variety of studies; however, for many cases, the sex of these specimens is unknown. Sexes of adult (> 5 years determined by tooth aging) Atlantic walruses (Odobenus rosmarus rosmarus) have been accurately determined in previous studies using mandible measurements. We tested the validity of this approach for Pacific walruses, and used full fusion of the mandibular symphysis to define adults. Using high precision digital calipers (± 0.01 mm), four measurements were taken either on the left or right side of 91 walrus mandibles: 80 modern mandibles (70 known-sex specimens; 10 unknown-sex specimens) and 11 archaeological mandibles of unknown sex. We used linear discriminant function analysis (LDFA) to determine what measurements best distinguished Pacific walrus males from females. Minimum mandible thickness had the most predictive power, whereas mandible length, height, and depth, were less predictive. Posterior probabilities indicated that LDFA classified the known-sex Pacific walruses with 100% accuracy, and unknown sex with ≥ 90% probability. The ability to define the sex of unknown individuals accurately could greatly increase the sample size of future projects dealing with skeletal remains, and will improve future research efforts.
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Bhaskar, Ravi, Naveen Kumar, Anjana S, Varalakshmi Chandrasekharan, and Ashwini Aithal P. "Morphometric Evaluation of Mental Foramen of Dry Adult Human Mandibles of South Indian Population and Their Clinical Correlation." International Journal of Anatomy and Research 10, no. 3 (September 5, 2022): 8419–24. http://dx.doi.org/10.16965/ijar.2022.174.
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Introduction: Morphometric assessment of mental foramina (MF) of the mandible for its variable position is considered to be helpful for the surgeons and dentists for the localized surgical procedures and for the anesthetists to execute nerve block practices. Hence the objective of the present study is to establish the morphometric variability in the position of MF in terms of gender in the mandibles of Southern Indian origin with possible clinical implications. Methods: The shape, size, and location of MF were measured on both sides of the mandible (n=92). Location of MF was established by measuring the distance from MF to the [1] mental symphysis [2] alveolar crest, [3] the base of the mandible, and [4] posterior border of the ramus of the mandible. All the morphometric data were analyzed statistically with a significance level of p<0.05. Results: The higher incidence (58.7%) of rounded MF was recorded. There were no cases of MF anterior to the first pre-molar and below the 1st molar. Most of them (45.7%) were below the 2nd premolar. There was a significant association between gender and the position of the MF (p=0.011). But, no association between gender and side as well as the shape was noted. Significant associations were found between gender and the distance from mental foramen to the posterior border of the ramus and also to the alveolar crest. A significant association between the gender and the positions of the MF was noted. Conclusion: The variations observed from previous studies might be related to the feeding habits of different regions which may ultimately, affect the development of mandibles. Prior knowledge regarding the common positions of MF in local populations is helpful in effective nerve blocks and maxillofacial surgeries. KEY WORDS: Mental foramen, mental nerve block, distal implant, mandible.
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Baskin, Jonathan Z., Brandon M. White, Amit Vasanji, Thomas E. Love, and Steven J. Eppell. "Mandible Biomechanics and Continuously Erupting Teeth: A New Defect Model for Studying Load-Bearing Biomaterials." Biomedicines 9, no. 7 (June 25, 2021): 730. http://dx.doi.org/10.3390/biomedicines9070730.
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Animals with elodont dentition and unfused mandible symphyses are hypothesized to have symmetric incisor morphology. Since these animals maintain their teeth by gnawing, they may provide physiologic feedback on mechanical function when unilateral mandible defects are created that manifest as ipsilateral changes in tooth structure. This defect model would potentially generate important information on the functional/mechanical properties of implants. Rats’ and rabbits’ mandibles and teeth are analyzed with µCT at baseline and post-intervention (n = 8 for each). Baseline incisors were compared. In a unilateral mandible pilot study, defects—ranging from critical size defect to complete ramus osteotomies—were created to assess effect on dentition (rats, n = 7; rabbits, n = 6). Within 90% confidence intervals, animals showed no baseline left/right differences in their incisors. There are apparent dental changes associated with unilateral defect type and location. Thus, at baseline, animals exhibit statistically significant incisor symmetry and there is an apparent relationship between mandible defect and incisor growth. The baseline symmetry proven here sets the stage to study the degree to which hemi-mandible destabilizing procedures result in measurable & reproducible disruption of dental asymmetry. In a validated model, an implant designed to function under load that prevents incisor asymmetry would provide supporting evidence that the implant has clinically useful load-bearing function.
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Newlands, Shawn D., Sreedhar Samudrala, and W. Kevin Katzenmeyer. "Surgical Treatment of Gunshot Injuries to the Mandible." Otolaryngology–Head and Neck Surgery 129, no. 3 (September 2003): 239–44. http://dx.doi.org/10.1016/s0194-5998(03)00481-9.
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OBJECTIVES: Our goal was to review and identify risk factors for complications from treatment of mandible fractures due to gunshot wounds. STUDY DESIGN AND SETTING: We conducted a retrospective review of treatment outcomes in 90 patients with gunshot wounds to the mandible treated over a 10-year period at 2 tertiary care centers. RESULTS: Our series of 90 patients with mandibular injuries due to gunshot wounds included 68 patients who underwent surgical procedures on the mandible. There were 14 complications in this group. Complications were more common in patients whose mandibles were rigidly fixated; however, these patients' injuries were more severe. Complications were significantly increased in patients who lost a segment of mandible in the injury. CONCLUSIONS: Complications were related to severity of injury and independent of treatment modality. SIGNIFICANCE: The complication rate for patients with gunshot injuries can be very high, particularly if bone is missing. Stabilization of remaining mandibular segments with potentially multiple subsequent reconstructive procedures is often required to restore mandibular continuity in these patients.
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Rahmat, S. J., and I. A. Koretsky. "Mandibular Morphology of the Mid-Miocene Seal Devinophoca claytoni (Carnivora, Phocidae, Devinophocinae)." Vestnik Zoologii 52, no. 6 (December 1, 2018): 509–20. http://dx.doi.org/10.2478/vzoo-2018-0052.
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Abstract During several excavations in Slovakia at the base of the Malé Karpaty Mountains (near the junction of the Morava and Danube Rivers), two skulls and numerous mandibular, dental and postcranial bones of early mid-Miocene (16.3–12.8 Ma) seals were collected. Isolated mandibles and many individual teeth were found at this locality, with some teeth in situ corresponding morphologically with the mandible and skull of Devinophoca claytoni, and others perfectly associating to the mandible and skull of the recently described Devinophoca emryi. Based on this material, two species of the previously unknown phocid subfamily Devinophocinae Koretsky et Holec, 2002 have been described. However, the mandibular morphology of the type species Devinophoca claytoni has remained unknown. Here, we present a first description of the mandible of this species. Morphological assessments reveal that the D. claytoni mandible has posterior alveoli larger than anterior; flat mandibular body low in height; alveoli of p4 larger than m1; and a unique devinophocine combination of incisors (I3/1) that differs from those in the extant subfamilies Cystophorinae (I2/1), Monachinae (I2/2) and Phocinae (I3/2).
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S., Shashidhar, and Sridevi N. S. "Anthropometric Analysis of Mental Foramen in Dry Human Mandibles in Karnataka." National Journal of Clinical Anatomy 08, no. 04 (October 2019): 148–52. http://dx.doi.org/10.1055/s-0039-3400838.
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Abstract Background and Objectives The mental foramen which is located on the anterior surface of the mandible is a bilateral opening transmitting mental nerves and vessels that supply important structures around. However, it is reported that the location of mental foramen varies across different races and genders, the awareness of which is vital in surgical interventions, anesthetic applications, and various other invasive procedures. Hence, the objectives of the present study were to study the location, size, and shape of mental foramina in dry human mandibles and to study the incidence of accessory mental foramina in human mandibles. Materials and Methods One hundred eighty dried mandibles were observed for the location, size, and shape of mental foramen. Digital Vernier calipers were used to measure the distance of right and left mental foramen from various locations like alveolar crest, symphysis menti, lower border of mandible, and posterior border of the ramus of mandible. The data were analyzed using SPSS 20 software. The position and number of accessory mental foramen were determined. Results The various positions of mental foramina studied revealed the most common type to be type IV as per the Tebo and Telford classification. The average horizontal diameter was slightly higher than the average vertical diameter in majority of the bones. Accessory mental foramina were observed in 3 mandibles. Conclusion The mental foramen was most commonly situated along the longitudinal axis of second premolar tooth and the shape of the mental foramen was found to be oval in 95% of the bones studied.
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Hiratsuka, Ken, and Shigeo Osato. "Variations in corpus and ramus measurements based on gonial angles in adult complete dentate mandibles." European Journal of Anatomy 27, no. 4 (July 2023): 383–94. http://dx.doi.org/10.52083/awym4087.
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This study aimed to reveal differences in the mandibular corpus and ramus measurements, volume (VOM), and gross weight of the mandible (GWOM) between the low and high gonial angles (L-GA and H-GA, respectively) in adult mandibles, and to evaluate the correlations between GAs and the measurement variables. Twenty-nine dried adult human complete dentate mandibles (L-GA ≤ 120°: 13 mandibles; H-GA: 125° ≥ GA: 16 mandibles) were measured using a lateral radiograph image-processing system, digital Vernier calipers, and an electric balance. The total length of the mandible (TLOM), corpus length (mental foramen– gonion [MeF’-Go’], mental foramen–mandibular foramen [MeF’-MaF’], and mandibular foramen–gonion [MaF’-Go’]), inter-ramus (bicondylar, bicoronion, and bigonion) widths (BiCoW, BiCorW, and BiGoW), GA width (GAW), condylar perpendicular height (CPH), the VOM, and GWOM were measured. Data were assessed using the exact binomial test, Mann–Whitney U test and Pearson’s correlation coefficient test. The MeF’- Go’ and MaF’-Go’, three inter-ramus widths, GAW, CPH, VOM, and GWOM in the L-GA group were significantly larger than those in the H-GA group. Significant negative correlations were found between GA size and multiple variables other than TLOM and BiCorW. Therefore, GA size was closely related to the enlarged morphometric dimensions of both the GA and the mandibular ramus in the posterior region of the mandibular corpus, as well as the volume and weight of the mandible, but it was not related to TLOM. These results indicate that the evaluation of GA size is useful for strategic dental treatment.
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Goyal, Nisha, Maneesha Sharma, Rasalika Miglani, Anil Garg, and P. K. Gupta. "Clinical significance of accessory foramina in adult human mandible." International Journal of Research in Medical Sciences 5, no. 6 (May 27, 2017): 2449. http://dx.doi.org/10.18203/2320-6012.ijrms20172427.
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Background: The mandible is the strongest and largest bone of facial skeleton. It consists of one horseshoe-shaped body and a pair of rami. On external surface of body in the midline there is a faint ridge i.e. symphysis menti indicating the line of fusion of two halves of mandible during development. The aim of this study is to describe the position and incidence of accessory foramina on the inner surface of the body and rami of both sides of mandible to provide simple important reliable surgical landmarks.Methods: The present study was conducted on 100 dried adult human mandibles. Bones which had deformities, asymmetries, external pathological changes and fractures were excluded from the present study.Results: In 97% cases at least one accessory foramen was observed on inner surface of mandible. The accessory lingual foramen was found to be constant finding with incidence of 81%. Frequency of infraspinous or sublingual foramen was 58%, of lateral foramen was 50% and that of accessory mandibular foramen was 39%.Conclusions: The anatomical knowledge about the common location and incidence of accessory foramina in mandible are important for surgeons and anaesthetists performing surgeries in the area around mandible. These accessory foramina transmit neurovascular bundles which provide accessory innervations to the roots of teeth. Thus proper knowledge of accessory foramina are important in relation to achieving complete inferior alveolar nerve block and for avoiding injury to neurovascular bundle passing through them.
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P.S. Guastaldi, Fernando. "A review of biomechanical studies for mandibular angle fracture internal fixation." Dentistry and Oral Maxillofacial Surgery 4, no. 1 (September 30, 2021): 01–14. http://dx.doi.org/10.31579/2643-6612/020.
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Mandible fractures correspond to 19-40% of all facial fractures. Among all mandible fractures, 12-30% are fractures of the mandibular angle. These fractures are mainly caused by sports activities, interpersonal violence and car accidents. The presence of the third molar and the thin transverse bone area seem to be responsible for the frequent involvement of the mandibular angle in facial fractures. Before the advent of antibiotics, a high frequency of infection was always associated after an open reduction in mandibular angle fractures. Wired osteosynthesis and maxillomandibular fixation (MMF) were traditional methods for fixing mandibular angle fractures. The limitation of both methods has influenced the development of new approaches for the treatment of mandibular angle fractures. Currently, osteosynthesis of mandibular angle fractures with plates and screws has become an effective treatment option. Several forms are described in the literature as: fixation of bone segments with a miniplate on the upper edge of the mandible, fixation with two miniplates, lag screw or by a single rigid plate on the lower edge of the mandible. The purpose of this study was to summarize the main characteristics of biomechanical studies such as the type of mandible source used, the plating techniques employed, the plate material, and the loading protocols used to evaluate the stability of the fixation methods. The Medline (PubMed) database was searched combining relevant terms and pertinent articles in English were included. Articles had to meet the following inclusion criteria: be in vitro biomechanical studies evaluating fixation methods for mandibular angle fractures. A total of 27 articles fulfilled the inclusion criteria. Synthetic mandibles (n=12), animal mandibles (n=9), and human cadaveric mandibles (n=5) were used as the sample source to perform the biomechanical analysis. One article used both synthetic and human cadaveric mandibles. Also, a variety of fixation techniques was described such as mini-plates, lag-screws, reconstruction plates, and three-dimensional plates. The materials of the bone plates used were: stainless steel, commercially pure titanium, titanium alloy or bioresorbable. However, there was inconsistency in reporting the materials and not all studies clearly stated the material of the bone plates. For the biomechanical analysis, there was a high variation among all studies regarding the loading protocols used. The same side of fixation, the anterior part of the mandible (central incisors) or the contralateral side were reported as the dentate regions in which the force was applied. For more than 2 decades, in vitro biomechanical studies have been used to help researchers and clinicians in the field of Oral and Maxillofacial Surgery to properly evaluate and compare the different devices and techniques available for the treatment of mandibular angle fractures. Also, biomechanical studies are important to answer questions on fatigue performance and fracture strength on the gross level.
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Gruntmejer, Kamil, Adam Bodzioch, and Dorota Konietzko-Meier. "Mandible histology in Metoposaurus krasiejowensis (Temnospondyli, Stereospondyli) from the Upper Triassic of Poland." PeerJ 9 (September 30, 2021): e12218. http://dx.doi.org/10.7717/peerj.12218.
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Recent studies that have systematically augmented our knowledge of dermal bones of the Late Triassic temnospondyl amphibian Metoposaurus krasiejowensis have mostly focused on shoulder girdle elements and the skull. So far, histological data on the mandible are still scant. For the present study, two mandibles have been examined, using 50 standard thin sections. Dermal bones of the mandible reveal a uniform diploë structure, with the external cortex consisting of moderately vascularised, parallel-fibred bone, as well as a distinct alternation of thick zones and thinner annuli. Dense bundles of well-mineralised Sharpey’s fibres are seen in the external cortex over the entire length of the mandible. The trabecular middle region is highly porous and well vascularised, showing small primary vascular canals and more numerous secondary osteons; irregular erosion spaces occur in large numbers as well. The thin and poorly vascular internal cortex consists of parallel-fibred bone. The articular is not a dermal bone in origin, having been formed of a thin layer of avascular cortex and a very extensive, trabecular middle region. In contrast to the dermal bones of the mandible, the articular developed from a cartilaginous precursor, as evidenced by numerous remains of calcified cartilage in the central parts of the bone. Histological variability is extremely high along the mandible, its anterior part being characterised by high compactness and biomechanically good resistance in contrast to the highly porous posterior parts. Distinct variations of bone thickness and degree of bone porosity in specific areas of the mandible, may be due to local differences in biomechanics during feeding. The microstructure of the mandible corroborates a previous study of the active and ambush predation strategy in metoposaurids.
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Felice, Pietro, Lorenzo Bonifazi, Maryia Karaban, Cesare Berti, Gerardo Pellegrino, and Carlo Barausse. "Dynamic Navigated “Sandwich” Technique: A Novel Surgical Approach for Safe Osteotomies in the Rehabilitation of an Atrophic Posterior Mandible: A Case Report." Methods and Protocols 4, no. 2 (May 16, 2021): 34. http://dx.doi.org/10.3390/mps4020034.
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A 56-year-old female patient with vertical atrophy of the right posterior mandible was treated adopting an interpositional bone block approach using a cancellous heterologous bone block. Osteotomies of the patient’s mandible were performed with the help of dynamic computer-assisted surgery using virtual anatomical patient information obtained from a cone beam computed tomography (CBCT). The use of the dynamic computer-assisted surgery allowed authors to perform the horizontal osteotomy line as planned preoperatively on the CBCT virtual reconstruction, trying to minimize the risks of the inlay technique. No neurological complications were observed after surgery. The inlay technique could benefit from the aid of dynamic navigation technologies in posterior atrophic mandibles, increasing the reproducibility of the technique. A likely safer method for performing osteotomies with the “sandwich” technique in the posterior atrophic mandible is reported.
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van der Wel, Hylke, Bingjiang Qiu, Fred K. L. Spijkervet, Johan Jansma, Rutger H. Schepers, and Joep Kraeima. "Morphological Variation of the Mandible in the Orthognathic Population—A Morphological Study Using Statistical Shape Modelling." Journal of Personalized Medicine 13, no. 5 (May 19, 2023): 854. http://dx.doi.org/10.3390/jpm13050854.
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The aim of this study was to investigate the value of 3D Statistical Shape Modelling for orthognathic surgery planning. The goal was to objectify shape variations in the orthognathic population and differences between male and female patients by means of a statistical shape modelling method. Pre-operative CBCT scans of patients for whom 3D Virtual Surgical Plans (3D VSP) were developed at the University Medical Center Groningen between 2019 and 2020 were included. Automatic segmentation algorithms were used to create 3D models of the mandibles, and the statistical shape model was built through principal component analysis. Unpaired t-tests were performed to compare the principal components of the male and female models. A total of 194 patients (130 females and 64 males) were included. The mandibular shape could be visually described by the first five principal components: (1) The height of the mandibular ramus and condyles, (2) the variation in the gonial angle of the mandible, (3) the width of the ramus and the anterior/posterior projection of the chin, (4) the lateral projection of the mandible’s angle, and (5) the lateral slope of the ramus and the inter-condylar distance. The statistical test showed significant differences between male and female mandibular shapes in 10 principal components. This study demonstrates the feasibility of using statistical shape modelling to inform physicians about mandible shape variations and relevant differences between male and female mandibles. The information obtained from this study could be used to quantify masculine and feminine mandibular shape aspects and to improve surgical planning for mandibular shape manipulations.
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Langlois, Caroline de Oliveira, Maria Carméli Correia Sampaio, Alexandre Emidio Ribeiro Silva, Nilza Pereira da Costa, and Maria Ivete Bolzan Rockenbach. "Accuracy of linear measurements before and after digitizing periapical and panoramic radiography images." Brazilian Dental Journal 22, no. 5 (2011): 404–9. http://dx.doi.org/10.1590/s0103-64402011000500010.
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The aim of this study was to evaluate the accuracy of linear measurements made on conventional and digitized periapical and panoramic radiographic images of dry human hemi-mandibles. Images from the posterior region of 22 dry human hemi-mandibles were obtained by conventional panoramic and periapical radiography technique. Using a digital caliper, 3 vertical measurements were marked directly on the dry hemi-mandibles (reference measurements) as well as on the tracing from the conventional radiographic images of the specimens made onto acetate paper sheet: Distance 1: between the upper limit of the alveolar ridge and the lower limit at the mandible base; Distance 2: between the upper limit of the alveolar ridge and the upper limit of the mandibular canal; Distance 3: between the lower limit of the mandibular canal and the lower limit of the mandible base. Next, the radiographs were digitized and the three measurements were made on the digital images using UTHSCSA Image Tool software. Data were analyzed statistically by one-way ANOVA (α=0.05). There was no statistically significant differences (p>0.05) between periapical and panoramic radiographs or between the measurements recorded using the digital caliper and UTHSCSA software compared with dry mandible specimens for Distances 1 (p=0.783), 2 (p=0.986) and 3 (p=0.129). In conclusion, the radiographic techniques evaluated in this study are reliable for vertical bone measurements on selected areas and the UTHSCA Image Tool software is an appropriate measurement method.
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Farkas, Leslie G., Jeffrey C. Posnick, and Tania M. Hreczko. "Growth Patterns of the Face: A Morphometric Study." Cleft Palate-Craniofacial Journal 29, no. 4 (July 1992): 308–14. http://dx.doi.org/10.1597/1545-1569_1992_029_0308_gpotfa_2.3.co_2.
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Age-related growth changes in the face and the relationships between its parts were calculated by using three vertical, two horizontal, and two projective surface measurements from 1,594 healthy North American Caucasians between 1 and 18 years of age. By 1 year, the width of the mandible was highly developed (80.2%) while its height reached only 66.6% of the eventual adult size. The mandible's height and width showed significant development between 1 and 5 years, while the face height, upper face height, face width, and the two face depth measurements exhibited continuous gradual growth after 5 years of age. In general, the face matured between 12 and 15 years in males and 2 years earlier in females. At 12 years, the upper face height, the mandible height, and the width of the face reached their mature size in females. At 15 years, the face height, mandible height, face width, and the depth of the mandible reached maturity in males.
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Echarri, Sebastian, Marcos D. Ercoli, M. Amelia Chemisquy, Guillermo Turazzini, and Francisco J. Prevosti. "Mandible morphology and diet of the South American extinct metatherian predators (Mammalia, Metatheria, Sparassodonta)." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 106, no. 4 (December 2015): 277–88. http://dx.doi.org/10.1017/s1755691016000190.
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ABSTRACTSparassodonta is a diverse group of extinct metatherian predators that include forms with diets ranging from omnivores to hypercarnivores, including potential bone-crushers and sabre-tooth specialised species. Most of the previous dietary studies on the group were based on qualitative approaches or dental morphometric indexes and/or bite force estimations. In this study, we explore the evolution of mandible shape and diet of Sparassodonta in a comparative phylogenetic framework, using geometric morphometric tools and allometric and discriminant analyses. We analysed the mandible shape of 142 extant species of marsupials and placental carnivores, and 15 fossil sparassodont species. We found that the relationship between shape and size of the mandible is strongly structured by phylogeny, where the more derived borhyaenoids tend to possess stronger and larger mandibles. Derived borhyaenoid sparassodonts and basal borhyaenoids were classified as hypercarnivores (with short and robust mandibular body). Hathliacynid were classified as mesocarnivores or as hypercarnivores, but with lower probabilities and less specialised morphologies (with a long and slender mandible). Although dental morphology suggests that most of the species of Sparassodonta would have been hypercarnivores, the robustness of the mandible seems to be informative regarding the prey size and degree of specialisation. The relationship between mandibular size and shape, and talonid/trigonid relative size, is strongly influenced by the phylogenetic legacy, suggesting that ecological factors could have influenced the evolution of the sparassodonts.
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Shroff, Neeta Gautam, Shamama Shaikh, Gautam A. Shroff, Vaishali Mandhana, and Sana Khan. "Morphometric analysis of adult human mandible and their ratios." Indian Journal of Clinical Anatomy and Physiology 10, no. 3 (October 15, 2023): 153–56. http://dx.doi.org/10.18231/j.ijcap.2023.034.
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Mandible is the strongest bone in the face region required for the process of mastication. The inferior alveolar nerve travels inside the bone in the mandibular canal to supply the lower teeth. The measurement of various parameters of mandible allows the proper localisation of nerve for anaesthetic block. Also, the ratios between factors assists during surgeries. A cross-sectional observational study was conducted on 97 dry adult human mandibles. Height of symphysis menti, ramus breadth and height, and distance of mandibular foramen from mandibular notch and base of mandible of both sides are measured. Ratios between ramus height and breadth and distances of mandibular foramen from above mentioned landmarks were computed. The mean height of symphysis menti was found to be 25.52 ± 4.32 mm. The mean values of height of ramus on right side was 46.18 ± 4.43 mm and on left was 46.57 ± 4.24 mm. The mean breadth of ramus was 32.29 ± 3.57 mm (right side) and 32.59 ± 3.75 mm (left side). It was found that mandibular foramen was closer to the mandibular notch than to the base of mandible on both sides. The ratios between the right and left side showed no significant differences.Inferior alveolar nerve block is required in various dental procedures for which mandibular foramen localisation is must. Dimensions of mandible help in surgical restructuring. Similarly, it aids in understanding the evolution of the bone.
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GASTAUER, MARKUS, LUCIO A. O. CAMPOS, and DIETER WITTMANN. "Handling sticky Resin by Stingless Bees: Adhesive Properties of Surface Structures." Anais da Academia Brasileira de Ciências 85, no. 3 (September 2013): 1189–96. http://dx.doi.org/10.1590/s0001-37652013000300018.
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Many Stingless Bees (Hymenoptera: Meliponini) like Tetragonisca angustula collect resin to defend their nests against intruders like ants or Robber Bees. Small portions of resin are attached to intruders bodies and extremities causing their immobilization. It has been observed that resin is removed easily from the bee's mandible but adheres strongly to the intruder's cuticle. We tested the hypothesis that resin sticks lesser to the mandibles of Stingless Bees than to the surface of intruders due to special surface structures or adhesive properties of these structures. The surface structures of the mandible of T. angustula and the trochanter of Camponotus sericeiventris were studied by scanning electron microscopy. To measure adhesion properties, selected surfaces were fixed on a fine glass pin and withdrawn from a glass tip covered with resin. The deformation of the glass pin indicates adhesion forces operating between the resin and the selective surface. The absolute value of the forces is computed from the glass pin's stiffness. It has been shown that resin sticks more to the smooth mandible of the bee than to the structured trochanter of the ant. A new hypothesis to be tested says that the bees might lubricate their mandibles with nectar or honey to reduce the resin's adhesion temporarily.
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Huang, Heng-Li, Ming-Tzu Tsai, Shih-Guang Yang, Kuo-Chih Su, Yen-Wen Shen, and Jui-Ting Hsu. "Mandible Integrity and Material Properties of the Periodontal Ligament during Orthodontic Tooth Movement: A Finite-Element Study." Applied Sciences 10, no. 8 (April 24, 2020): 2980. http://dx.doi.org/10.3390/app10082980.
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We used the finite-element method (FEM) to investigate the effects of jawbone model integrity and the material properties of the periodontal ligament (PDL) on orthodontic tooth movement. Medical imaging software and computer-aided design software were used to create finite-element models of a partial and complete mandibles based on dental cone beam computed tomography images of the human skull. Additionally, we exerted an orthodontic force on the canine crown in the direction of an orthodontic miniscrew under a lower molar root to compare the von Mises strain on the canine PDL in three models: a partial mandible model under orthodontic force (Model 1), a complete mandible model under orthodontic force (Model 2), and a complete mandible model under orthodontic force with clench occlusion in the intercuspal position (ICP; Model 3). Additionally, in the complete mandible model under orthodontic force with ICP occlusion, we analyzed the effects of a PDL with a low (Model 4), moderate (Model 5), and high (Model 6) linear elastic modulus and a PDL a bilinear elastic modulus (Model 7). The simulation results for mandible integrity indicated that the maximum von Mises strains on the canine PDL for Models 1, 2, and 3 were 0.461, 0.394, and 1.811, respectively. Moreover, for the models with different PDL material properties, the maximum von Mises strains on the canine PDLs for Models 4, 5, 6, and 7 were 6.047, 2.594, 0.887, and 1.811, respectively. When the FEM was used to evaluate tooth movement caused by orthodontic force, the transformation of a complete mandible model into a partial mandible model or alteration of the elastic modulus of the PDL influenced the biomechanical responses of the PDL. Additionally, the incorporation of daily ICP occlusion resulted in a larger effect.
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Martinez-Maza, Cayetana, Antonio Rosas, Samuel García-Vargas, Almudena Estalrrich, and Marco de la Rasilla. "Bone remodelling in Neanderthal mandibles from the El Sidrón site (Asturias, Spain)." Biology Letters 7, no. 4 (February 9, 2011): 593–96. http://dx.doi.org/10.1098/rsbl.2010.1188.
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Skull morphology results from the bone remodelling mechanism that underlies the specific bone growth dynamics. Histological study of the bone surface from Neanderthal mandible specimens of El Sidrón (Spain) provides information about the distribution of the remodelling fields (bone remodelling patterns or BRP) indicative of the bone growth directions. In comparison with other primate species, BRP shows that Neanderthal mandibles from the El Sidrón (Spain) sample present a specific BRP. The interpretation of this map allows inferences concerning the growth directions that explain specific morphological traits of the Neanderthal mandible, such as its quadrangular shape and the posterior location of the mental foramen.