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1.
Nat Commun ; 12(1): 3420, 2021 06 08.
Artículo en Inglés | MEDLINE | ID: mdl-34103535

RESUMEN

Theory shows how sexual selection can exaggerate male traits beyond naturally selected optima and also how natural selection can ultimately halt trait elaboration. Empirical evidence supports this theory, but to our knowledge, there have been no experimental evolution studies directly testing this logic, and little examination of possible associated effects on female fitness. Here we use experimental evolution of replicate populations of broad-horned flour beetles to test for effects of sex-specific predation on an exaggerated sexually selected male trait (the mandibles), while also testing for effects on female lifetime reproductive success. We find that populations subjected to male-specific predation evolve smaller sexually selected mandibles and this indirectly increases female fitness, seemingly through intersexual genetic correlations we document. Predation solely on females has no effects. Our findings support fundamental theory, but also reveal unforseen outcomes-the indirect effect on females-when natural selection targets sex-limited sexually selected characters.


Asunto(s)
Escarabajos/genética , Aptitud Genética , Carácter Cuantitativo Heredable , Selección Genética , Caracteres Sexuales , Animales , Evolución Biológica , Tamaño Corporal , Cruzamiento , Femenino , Variación Genética , Masculino , Mandíbula/anatomía & histología , Tamaño de los Órganos , Fenotipo , Conducta Predatoria
2.
Mol Med Rep ; 23(4)2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33604680

RESUMEN

MicroRNA­21 (miR­21) is a small non­coding RNA that is differentially expressed during tooth development, particularly during amelogenesis. Although orthodontic tooth movement and the innate immune response are impaired, miR­21 knockout mice demonstrate no obvious skeletal phenotype. However, the consequence of miR­21 knockout on tooth phenotype and corresponding alveolar bone is unknown. The current study utilized landmark­based geometric morphometrics to identify anatomical dissimilarities of the three lower and upper molars, and the corresponding alveolar bone, in miR­21 knockout and wild­type control mice. The anatomical structures were visualized by microcomputer tomography. A total of 36 and 38 landmarks were placed on mandibular and maxillary molars, respectively. For the alveolar bone, 16 landmarks were selected on both anatomical sites. General Procrustes analysis revealed significantly smaller molars and dimensions of the alveolar bone in the mandible of the miR­21 knockout mice when compared with wild­type controls (P=0.03 and P=0.04, respectively). The overall dimension of the mandible was reduced by the lack of miR­21 (P=0.02). In the maxilla, the dimension of the alveolar bone was significant (P=0.02); however, this was not observed in the molars (P=0.36). Based on principal component analysis, no changes in shape for any of the anatomical sites were observed. Dental and skeletal jaw length were calculated and no prognathism was identified. However, the fluctuating asymmetry of the molars in the mandible and the maxilla was reduced in the miR­21 knockout mice by 38 and 27%, respectively. Taken together, the results of the present study revealed that the molars in the mandible and the dimension of the respective alveolar bone were smaller in miR­21 mice compared with wild­type littermates, suggesting that miR­21 influences tooth development.


Asunto(s)
Tamaño Corporal/genética , Mandíbula/anatomía & histología , MicroARNs/genética , Diente/anatomía & histología , Animales , Humanos , Mandíbula/crecimiento & desarrollo , Maxilar/anatomía & histología , Maxilar/crecimiento & desarrollo , Ratones , Ratones Noqueados , Diente Molar/anatomía & histología , Diente Molar/crecimiento & desarrollo , Diente/crecimiento & desarrollo
3.
Br J Oral Maxillofac Surg ; 59(2): 179-183, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33483156

RESUMEN

The aim of this study was to determine the course of marginal mandibular nerve (MMN) in relation to the inferior border of the mandible from the gonion until its terminal insertion to the depressor anguli oris, relating the position to a palpable anatomical landmark with emphasis on the depth of the nerve in relation to platysma and the deep cervical fascia. Twelve fresh adult cadavers were dissected and the mandibular base was contoured using needles with 5mm gaps, starting from the mandibular angle to the muscular termination point of the nerve bilaterally. The distance between the MMN and the mandibular base and total length of the nerve was measured bilaterally. The highest levels of MMN were measured 6.9mm and 6.5mm above, and the lowest levels were measured 4mm and 3mm below the mandibular base on right and left sides, respectively. The mean (SD) total length of the nerve until the muscular termination point was calculated 33.57 (3.41) mm on the right and 33.51 (4.88) mm on the left side. Previous publications that we had read all fell short of defining the schematic pathway of the nerve, as the described landmarks were of a combination of bone and soft tissue, which are not always clinically reliable. We have overcome this difficulty by standardising the inferior border of the mandible as a point in order to trace the marginal mandibular branch pathway. It originates along the gonion and ends at the second premolar tooth area.


Asunto(s)
Nervio Facial , Mandíbula , Adulto , Cadáver , Nervio Facial/anatomía & histología , Cabeza , Humanos , Mandíbula/anatomía & histología , Nervio Mandibular/anatomía & histología
4.
J Fish Biol ; 98(5): 1371-1384, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33440014

RESUMEN

Environmental disasters affecting Brazilian rivers have been frequent recently, especially involving mining activities. Two recent dam-rupture events suddenly released millions of cubic meters of iron tailings downstream into two major Brazilian watersheds. These events generated major losses to the environment and human life. Additionally, the biodiversity in both watersheds was still incompletely known. Two new species of the armoured catfish genus Hypostomus were discovered in the Rio Paraopeba and surrounding rivers of the Rio São Francisco Basin. The species share some main characteristics including a depressed body, large dark spots on a clearer background and the absence of keels on flanks. However, while one species (Hypostomus freirei sp. n.) has a large mandibular ramus and numerous slender teeth, the other (Hypostomus guajupia sp. n.) has a shorter mandibular ramus and few robust teeth. The discovery of these two new mid-sized fish species emphasizes the presumption that the effects of major environmental disasters cannot be fully estimated as local biodiversity is not completely known. This discovery in a recently devastated area also shows that tough environmental laws for the protection, supervision and mitigation of major impacts are urgently needed in developing countries.


Asunto(s)
Biodiversidad , Bagres/anatomía & histología , Bagres/clasificación , Animales , Brasil , Desastres , Mandíbula/anatomía & histología , Minería , Ríos , Especificidad de la Especie , Diente/anatomía & histología
5.
Medicine (Baltimore) ; 99(43): e22778, 2020 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-33120788

RESUMEN

BACKGROUND: To analyze the sagittal positions of the mandibular prominence and maxillary central incisors in adult Chinese Han men to establish their aesthetic profile characteristics. METHODS: Seventy-four Chinese Han men aged 18 to 40 years underwent cone beam computed tomography for detecting the distances between Glabella and Subnasale, Subnasale and Menthon of soft tissue, Condyle and Gonion, Pogonion and Pogonion's Anterior Limit Line, Facial Axis point of maxillary central incisor and the Goal Anterior Limit Line as well as the angle of the Occlusal Plane. Dolphin Imaging and Photoshop software packages were used to generate silhouette profiles. Thirteen orthodontists assessed the silhouette profiles and assigned visual analog scale scores. Scores >70 were assigned to the aesthetic (group 1), scores of 60to 70 to the general (group 2), scores of 50 to 60 to the acceptable (group 3), and scores of <50 to the unaesthetic profile (group 4). RESULTS: A total of 15 men were assigned to group 1, 35 to group 2, 14 to group 3, and 10 to group 4. There were no significant differences in the variables examined between groups 1, 2, and 3, but comparing group 1 with group 4, Pogonion and Pogonion's Anterior Limit Line (1.16 ±â€Š2.61 mm vs -1.44 ±â€Š2.92 mm, P = .046) and Facial Axis-Goal Anterior Limit Line (-0.61 ±â€Š2.54 mm vs 1.70 ±â€Š2.62 mm, P = .038) there were significant differences. CONCLUSION: Compared with the unaesthetic profile group, the sagittal positions of the maxillary central incisors were slightly posterior, and the chin was slightly anterior in adult Chinese Han men with an aesthetic profile.


Asunto(s)
Grupos Étnicos , Incisivo/anatomía & histología , Incisivo/diagnóstico por imagen , Maxilar/anatomía & histología , Maxilar/diagnóstico por imagen , Adolescente , Adulto , Cefalometría/métodos , Mentón/anatomía & histología , Mentón/diagnóstico por imagen , China , Tomografía Computarizada de Haz Cónico/métodos , Humanos , Masculino , Mandíbula/anatomía & histología , Mandíbula/diagnóstico por imagen , Estudios Prospectivos , Valores de Referencia , Adulto Joven
6.
Leg Med (Tokyo) ; 47: 101770, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32795932

RESUMEN

BACKGROUND: A missing mandible is a common problem in facial identification cases requiring forensic facial approximation or reconstruction. The Sassouni and Sassouni-Plus methods which are currently used to predict the missing mandible from the cranium produce low levels of accuracy. AIMS: This study proposes a new method for the estimation of the overall dimensions of the mandible based upon linear cranial measurements, the proposed method has the potential to be utilised in the facial reconstruction of a range of adult skulls with dentition. SAMPLE AND METHOD: 21 measurements were taken from a sample of 90 skulls, 44 male, 43 female and three juvenile, originating from 9 different geographical areas. Ordinary least-squares regression, hierarchical cluster analysis and analysis of variance (ANOVA) were used to investigate trends in the data and to produce equations for the estimation of condylar height, corpus length and anterior height. CONCLUSION: When tested the equations produced an overall mean error of 0.09 mm with a standard deviation of ±4.84. The proposed method offers an improvement upon the currently used methods. It can be used to estimate the overall mandibular dimensions with a good level of accuracy.


Asunto(s)
Restos Mortales/anatomía & histología , Cefalometría/métodos , Cara/anatomía & histología , Antropología Forense/métodos , Mandíbula/anatomía & histología , Adolescente , Adulto , Anciano , Niño , Grupos de Población Continentales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Cráneo/anatomía & histología , Adulto Joven
7.
BMC Evol Biol ; 20(1): 95, 2020 07 31.
Artículo en Inglés | MEDLINE | ID: mdl-32736512

RESUMEN

BACKGROUND: Adaptive radiations are characterized by extreme and/or iterative phenotypic divergence; however, such variation does not accumulate evenly across an organism. Instead, it is often partitioned into sub-units, or modules, which can differentially respond to selection. While it is recognized that changing the pattern of modularity or the strength of covariation (integration) can influence the range or rate of morphological evolution, the relationship between shape variation and covariation remains unclear. For example, it is possible that rapid phenotypic change requires concomitant changes to the underlying covariance structure. Alternatively, repeated shifts between phenotypic states may be facilitated by a conserved covariance structure. Distinguishing between these scenarios will contribute to a better understanding of the factors that shape biodiversity. Here, we explore these questions using a diverse Lake Malawi cichlid species complex, Tropheops, that appears to partition habitat by depth. RESULTS: We construct a phylogeny of Tropheops populations and use 3D geometric morphometrics to assess the shape of four bones involved in feeding (mandible, pharyngeal jaw, maxilla, pre-maxilla) in populations that inhabit deep versus shallow habitats. We next test numerous modularity hypotheses to understand whether fish at different depths are characterized by conserved or divergent patterns of modularity. We further examine rates of morphological evolution and disparity between habitats and among modules. Finally, we raise a single Tropheops species in environments mimicking deep or shallow habitats to discover whether plasticity can replicate the pattern of morphology, disparity, or modularity observed in natural populations. CONCLUSIONS: Our data support the hypothesis that conserved patterns of modularity permit the evolution of divergent morphologies and may facilitate the repeated transitions between habitats. In addition, we find the lab-reared populations replicate many trends in the natural populations, which suggests that plasticity may be an important force in initiating depth transitions, priming the feeding apparatus for evolutionary change.


Asunto(s)
Cíclidos/anatomía & histología , Ecosistema , Conducta Alimentaria , Animales , Maxilares/anatomía & histología , Lagos , Malaui , Mandíbula/anatomía & histología , Modelos Biológicos , Faringe/anatomía & histología , Filogenia , Agua
8.
Int. j. morphol ; 38(4): 924-932, Aug. 2020. tab, graf
Artículo en Español | LILACS | ID: biblio-1124878

RESUMEN

El canal mandibular es una estructura de especial interés considerando que es vital su preservación durante actos clínicos. Por encontrarse al interior del hueso requiere un estudio in vivo mediante el uso rayos X, involucrando técnicas entre las que destaca la TC Cone Beam (TCCB). El objetivo de este trabajo es comparar la biometría del canal mandibular humano obtenida en la disección anatómica con la morfometría de las imágenes generadas en TCCB. A partir de cortes coronales realizados en los sectores anterior, medio y posterior del canal mandibular en mandíbulas secas, y mediante imágenes generadas en la TCCB, se obtuvieron 216 mediciones en cada una de técnicas aplicadas. Las mediciones lineales del canal mandibular se efectuaron utilizando marcadores radiopacos que fueron dispuestos en relación a las paredes vecinas que corresponden a las corticales alveolar/residual, basal, interna y externa. Se midió el diámetro vertical y transversal del canal, junto con las distancias entre la cortical alveolar/residual y basal, y entre la cortical interna y externa. Se obtuvieron los valores promedio de cada una de las mediciones lineales, tanto de la biometría en la mandíbula seca como de la morfometría realizada en la TCCB. Luego se determinó las diferencias estadísticas de cada medición (L1-L6 y D1-D2) entre ambas técnicas, utilizando la prueba de correlación de Pearson, donde se obtuvo una correlación positiva muy alta (p›0,987). Adicionalmente se determinó que las mediciones no se ven afectadas por el sector del canal analizado (p›0,987). En las mediciones realizadas L1-L6 y D1-D2, no se encontraron diferencias significativas entre la biometría con respecto a las medidas de morfometría hechas en las imágenes de la TCCB. Las medidas L4 y L5 son las que ofrecen menor diferencias porcentuales con otras investigaciones, debido a una menor absorción de las corticales involucradas.


The mandibular canal is a structure of special interest, considering that its preservation during clinical procedures is vital. Given its location inside the bone, in vivo studies including X-rays and Cone Beam CT (CBCT) analysis are among the techniques required for an evaluation. The aim of this paper is to compare biometrics of the human mandibular canal from an anatomic dissection, with the morphometry of images obtained with CBCT. In this study, 216 measurements were obtained from cross sections carried out in the anterior, middle and posterior sectors of the mandibular canal in dry jaws, through CBCT images. Linear measurements of the mandibular canal were carried out using radiopaque markers that were arranged with respect to the outlying walls that correspond to the alveolar/residual, basal, internal and external corticals. The vertical and transverse diameters of the canal was measured, along with the distances between the alveolar/residual and basal cortex, and between the internal and external corticals. The average values of each of the linear measurements were obtained, both of the biometrics in the dry jaw and the morphometry performed in the CBCT. Then the statistical differences of each measurement (L1-L6 and D1-D2) between both techniques were determined, using the Pearson correlation test, where a very high positive correlation was obtained (p ›0.987). Additionally, it was determined that measurements are not affected by the sector of the analyzed channel (p ›0.987). The measurements made L1-L6 and D1-D2, no significant differences were found between the biometrics with respect to the morphometry measurements made in the CBCT images. Measures L4 and L5 are those that offer the lowest percentage differences with other research, due to lower absorption of the corticals involved.


Asunto(s)
Humanos , Mandíbula/anatomía & histología , Mandíbula/diagnóstico por imagen , Disección , Tomografía Computarizada de Haz Cónico
9.
Int. j. morphol ; 38(4): 899-902, Aug. 2020. graf
Artículo en Español | LILACS | ID: biblio-1124873

RESUMEN

La correcta identificación del canal mandibular es esencial cuando se pretende realizar procedimientos quirúrgicos del sector posterior o incluso odontología clínica. La tomografía computarizada de haz cónico (CBCT) utiliza diferentes planos para la evaluación de este. Para conocer las variaciones anatómicas del canal mandibular se lleva a cabo un estudio en 100 adultos mayores de 30 años, donde la ubicación, la forma y la orientación se estudia mediante la tomografía computarizada de haz cónico. Así, el principal objetivo de nuestro estudio es conocer la variabilidad y tipo de presentación del canal bífido en el Canal mandibular en pacientes dentados o parcialmente edéntulos adultos mayores de 30 años.


The correct identification of the mandibular canal is essential when trying to perform surgical procedures in the posterior sector or even clinical dentistry. Computed tomography (CBCT) uses different planes for the evaluation of this. In order to know the anatomical variations of the mandibular canal, a study is carried out in 100 adults over 30 years of age, where the location, shape and orientation is studied by cone beam computed tomography. The main objective of our study is to know the variability and type of presentation of the bifid canal in the mandibular duct in dentate or partially edentulous adult patients over 30 years.


Asunto(s)
Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Mandíbula/anatomía & histología , Mandíbula/diagnóstico por imagen , Estudios Transversales , Estudios Retrospectivos , Factores de Edad , Tomografía Computarizada de Haz Cónico , Variación Anatómica
10.
Head Face Med ; 16(1): 13, 2020 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-32513223

RESUMEN

BACKGROUND: The bone thickness of the human mandibular ramus is an important parameter in mandibular surgeries. The aim of this study was to systematically measure the bicortical bone thickness, the ramus dimensions and the position of the lingula. The measurements were tested on significant correlations to the patients' parameters. METHODS: Based on CBCT scans 150 rami were reconstructed as 3D polygon surfaces. An anatomical grid was adapted to the ramus surface to mark the bone thickness measurement points and to achieve comparability between the measurements on different mandibles. The bone thickness, ramus height, ramus width and the gonion angle were measured. A cluster analysis was performed with these parameters to identify clinically relevant groups with anatomical similarities. RESULTS: The median distribution of the bone thickness was calculated and visualized in a pseudo-colour map. The mean ramus height was 44.78 mm, the mean width was 31.31 mm and the mean gonion angle was 124.8°. The average distance from the lingula to the dorsal tangent was 53% of the total width and its distance to the caudal tangent was 65% of the total height. Significant correlations between the bone thickness and the ramus proportions could be identified. Age and sex had no significant influence on the mean bone thickness. The measured rami could be divided into two groups by cluster analysis. CONCLUSION: The dimensions of the human mandibular ramus can be determined from 3D reconstructed surface models from CBCT scans. Measurements could be made comparable by applying an anatomically oriented grid. A cluster analysis allowed the differentiation of two groups with different bone thickness distributions and geometries, which can be used for the optimization of osteosynthesis systems and their precision of adaptation to different ramus morphologies.


Asunto(s)
Mandíbula , Procedimientos Quirúrgicos Ortognáticos , Tomografía Computarizada de Haz Cónico Espiral , Diente , Proteínas Adaptadoras Transductoras de Señales , Humanos , Mandíbula/anatomía & histología , Mandíbula/diagnóstico por imagen
11.
Int. j. morphol ; 38(3): 714-719, June 2020. tab, graf
Artículo en Inglés | LILACS | ID: biblio-1098310

RESUMEN

The morphological variations of the mental foramen (MF) and mandibular foramen (MBF) have been studied for several years, and the prevalence and morphometric characteristics of double and triple foramina have been reported. The objective of this study was to establish the prevalence of variations in the MF and MBF, and to carry out a morphometric analysis of a Chilean population using digital panoramic radiographs. The study included 927 radiographs; the observed prevalence of double MF was 2.58 %, while the prevalence of double MBF was 1.51 %. No cases of triple foramina were found. In men, double MF was found more frequently in the left hemiarch (64.28 % of cases), while in women it was more frequent in the right hemiarch (80 %). Double MBF was found more frequently in the right hemiarch in women (80 % of cases), while the distribution between left and right in men was even. The mean area, width and height of the double MF were 5.46 mm2, 2.77 mm and 2.57 mm respectively. The means of the same morphometric measurements in double MBF were 6.37 mm2, 2.27 mm and 3.19 mm respectively. In both foramina, statistically significant differences were only found between the height of the foramen and the age of the subjects, with the observation that the greater the subject's age, the smaller the height. Dental surgeons must take these anatomical variants into consideration in clinical and surgical actions; timely diagnosis by radiograph is important to avoid possible complications.


Las variaciones morfológicas del foramen mental (FM) y mandibular (FMB) han sido estudiadas durante varios años, reportándose su prevalencia y las características morfométricas de forámenes dobles y triples. El objetivo de este estudio fue establecer la prevalencia de variaciones de los FM y FMB y realizar un análisis morfométrico a través de radiografías panorámicas digitales de una muestra de población chilena. En el estudio se incluyeron 927 radiografías y se observó una prevalencia de FM doble de 2,58 %, mientras que la prevalencia de FMB doble fue de 1,51 %. No se encontraron casos de forámenes triples. En hombres, el FM doble se encontró mayoritariamente en la hemiarcada izquierda (64,28 % de los casos), mientras que en mujeres fue en la hemiarcada derecha (80% de los casos). Para el caso de los FMB dobles, en mujeres se presentó mayoritariamente en la hemiarcada derecha (80 % de los casos), mientras que en hombres fue equitativo en ambos lados. El promedio del área, ancho y alto de los FM dobles fue de 5,46 mm2, 2,77 mm y 2,57 mm, respectivamente. Asimismo, los promedios de estas medidas morfométricas para el FMB doble fueron 6,37 mm2, 2,27 mm y 3,19 mm, respectivamente. Para ambos forámenes sólo se encontraron diferencias estadísticamente significativas entre el alto y la edad de los sujetos, observando que, a mayor edad menor era el alto del foramen. Los cirujanos dentistas deben tener en consideración estas variantes anatómicas para la realización de distintas acciones clínicas y quirúrgicas, su diagnóstico radiográfico oportuno es importante para prevenir posibles complicaciones.


Asunto(s)
Humanos , Masculino , Femenino , Adolescente , Adulto , Persona de Mediana Edad , Anciano , Anciano de 80 o más Años , Adulto Joven , Variación Anatómica , Foramen Mental/anatomía & histología , Foramen Mental/diagnóstico por imagen , Mandíbula/anatomía & histología , Mandíbula/diagnóstico por imagen , Radiografía Panorámica , Prevalencia , Estudios Transversales , Distribución por Edad y Sexo
12.
J Morphol ; 281(6): 662-675, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32356928

RESUMEN

The Polynemidae is a family of primarily marine fishes with eight genera and 42 extant species. Many aspects of their morphology are largely unknown, with few reports about their osteology and barely any information on their myology. This paper describes and illustrates in detail all facial and branchial muscles of representative species of polynemids. Our analysis demonstrates the existence of several remarkable and previously unknown specializations in the polynemid musculature. The aponeurotic and completely independent origin of the pars promalaris of the adductor mandibulae is apparently unique among percomorphs. The differentiation of this section into lateral and medial subsections; the total separation of the promalaris from the retromalaris; the differentiation of the pars primordialis of the levator arcus palatini into external and internal subsections are also uncommon features of polynemids that are shared by sciaenids, thus supporting the hypothesis of a closer relationship between these families.


Asunto(s)
Branquias/anatomía & histología , Músculos/anatomía & histología , Perciformes/anatomía & histología , Animales , Cara/anatomía & histología , Cabeza/anatomía & histología , Mandíbula/anatomía & histología
13.
Plast Reconstr Surg ; 146(3): 622-632, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32459733

RESUMEN

BACKGROUND: Facial allotransplantation including the temporomandibular joints may improve the functional outcomes in face transplant candidates who have lost or damaged this joint. METHODS: Linear and angular measurements were taken in 100 dry skulls and mandibles and in 100 three-dimensionally-reconstructed facial computed tomographic scans to determine the variability of the temporomandibular joint, glenoid fossa, and mandible. A vascular study was performed in six fresh cadaveric heads, followed by harvest of the face allograft in three heads. Next, four heads were used for mock transplantation (two donors and two recipients). The full facial allograft included four different segments: a Le Fort III, a mandibular tooth-bearing, and two condyle and temporomandibular joint-bearing segments. Statistical analysis was performed using SAS software. RESULTS: In only one-third of the skulls, the condylar shape was symmetric between right and left sides. There was a wide variability in the condylar coronal (range, 14.3 to 23.62 mm) and sagittal dimensions (range, 5.64 to 10.96 mm), medial intercondylar distance (range, 66.55 to 89.91 mm), and intercondylar angles (range, 85.27 to 166.94 degrees). This high variability persisted after stratification by sex, ethnicity, and age. The temporomandibular joint was harvested based on the branches of the superficial temporal and maxillary arteries. The design of the allograft allowed fixation of the two condyle and temporomandibular joint-bearing segments to the recipient skull base, preserving the articular disk-condyle-fossa relationship, and differences were adjusted at the bilateral sagittal split osteotomy sites. CONCLUSION: Procurement and transplantation of a temporomandibular joint-containing total face allograft is technically feasible in a cadaveric model.


Asunto(s)
Trasplante Facial/métodos , Mandíbula/trasplante , Osteotomía Le Fort/métodos , Hueso Temporal/trasplante , Articulación Temporomandibular/cirugía , Adulto , Anciano , Aloinjertos , Cadáver , Femenino , Humanos , Masculino , Mandíbula/anatomía & histología , Persona de Mediana Edad , Hueso Temporal/anatomía & histología , Articulación Temporomandibular/anatomía & histología , Adulto Joven
14.
Med. oral patol. oral cir. bucal (Internet) ; 25(3): e337-e345, mayo 2020. ilus, tab, graf
Artículo en Inglés | IBECS | ID: ibc-196319

RESUMEN

BACKGROUND: This study evaluated the epidemiological and morphological features of the mandibular incisive canal (MIC) using cone beam computed tomography (CBCT) in a significant sample of subjects in Brazil. MATERIAL AND METHODS: This retrospective, multicenter study assessed 847 CBCT scans performed at four oral imaging centers. The sample comprised CBCT images acquired from dentate individuals who presented at least from tooth 35 to tooth 45 in the anterior mandible region. Data regarding patient sex and age, and MIC linear measurements (length and diameter in mm), anatomical distances (to the alveolar, buccal and lingual cortexes, inferior border of the mandible, and adjacent teeth apexes), and location were obtained. RESULTS: The MIC was more prevalent in women (76.3% [p < 0.001]) between the fourth and sixth decades of life (p < 0.001). It was present bilaterally (p < 0.001) and exhibited a mean length of 7.7 mm (standard deviation [SD]=3.7 mm). Spearman correlation and logistic regression analysis revealed collinearity between age and linear measurements (p < 0.05). The mean distances varied from the initial to the final portion of the MIC, respectively, in relation to the buccal cortex (mean = 2.6 mm, SD = 1.27; mean=3.96 mm; SD =1 .43), to lingual cortex (mean=5.13 mm; SD=1.7; mean = 4.61 mm, SD = 1.65), and to the inferior mandibular border (mean = 9.32 mm, SD = 1.92; mean=8.76 mm, SD = 2.07 mm). The difference in the proximity of the MIC to the apex of the inferior lateral incisor was statistically significant (p < 0.05). CONCLUSIONS: Results of this study revealed a high prevalence of MIC with a bilateral pattern in women who were between the fourth and sixth decades of life. Both the distance between the MIC and the lingual cortex of the mandibular alveolar bone, and the diameter of the MIC, decreased as its trajectory assumed a more anterior position


No disponible


Asunto(s)
Humanos , Masculino , Femenino , Adolescente , Adulto Joven , Adulto , Persona de Mediana Edad , Anciano , Mandíbula/diagnóstico por imagen , Tomografía Computarizada de Haz Cónico/métodos , Mandíbula/anatomía & histología , Estudios Retrospectivos , Odontometría , Radiografía Panorámica , Estadísticas no Paramétricas , Análisis de Varianza , Factores Sexuales , Factores de Edad
15.
Eur. j. anat ; 24(3): 229-234, mayo 2020. tab, ilus
Artículo en Inglés | IBECS | ID: ibc-191472

RESUMEN

The incidence of a coronoid foramen in a live human subject is rare and hence the scarcity of the literature. The knowledge of any such anatomi-cal variation is important, as surgical procedures on the mandible are regularly performed by dental as well as oral and maxillofacial surgeons. The current script details anomalous morphology of an isolated coronoid foramen in the mandible of a 16-year-old female Saudi patient, which is a first ever documented case along with the presence of two separate accessory mandibular canals encoun-tered during routine dental investigations. A high spatial resolution three-dimensional cone beam computed tomography (CBCT) was used as a di-agnostic investigative method so as to allow an accurate three-dimensional analysis of mandibular coronoid foramen and accessory mandibular canal variations. These variations were documented and a detailed review of literature done. The script fo-cuses on the variations themselves, and the clini-cal implications of the presence of such variations. A thorough understanding of anatomical variants in the mandible and their neurovascular contents al-ways determines the success of any procedural anesthesia, the prevention of surgical misadven-ture and the etiology of pathologic processes


No disponible


Asunto(s)
Humanos , Femenino , Adolescente , Mandíbula/anatomía & histología , Mandíbula/diagnóstico por imagen , Variación Anatómica , Tomografía Computarizada de Haz Cónico/métodos , Radiografía Panorámica
16.
Sci Rep ; 10(1): 5842, 2020 04 03.
Artículo en Inglés | MEDLINE | ID: mdl-32245989

RESUMEN

Accurate localisation of mandibular canals in lower jaws is important in dental implantology, in which the implant position and dimensions are currently determined manually from 3D CT images by medical experts to avoid damaging the mandibular nerve inside the canal. Here we present a deep learning system for automatic localisation of the mandibular canals by applying a fully convolutional neural network segmentation on clinically diverse dataset of 637 cone beam CT volumes, with mandibular canals being coarsely annotated by radiologists, and using a dataset of 15 volumes with accurate voxel-level mandibular canal annotations for model evaluation. We show that our deep learning model, trained on the coarsely annotated volumes, localises mandibular canals of the voxel-level annotated set, highly accurately with the mean curve distance and average symmetric surface distance being 0.56 mm and 0.45 mm, respectively. These unparalleled accurate results highlight that deep learning integrated into dental implantology workflow could significantly reduce manual labour in mandibular canal annotations.


Asunto(s)
Tomografía Computarizada de Haz Cónico , Aprendizaje Profundo , Mandíbula/diagnóstico por imagen , Tomografía Computarizada de Haz Cónico/métodos , Humanos , Imagenología Tridimensional , Mandíbula/anatomía & histología , Mandíbula/cirugía
17.
Plast Reconstr Surg ; 145(5): 963e-974e, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32332545

RESUMEN

BACKGROUND: The aim of this study was to evaluate the effects of the use of computer-aided design and manufacturing cutting and drilling guides with prebent titanium plates for the correction of skeletal class III malocclusion. METHODS: In this prospective, randomized, controlled clinical trial, 46 patients with skeletal class III malocclusion were randomly assigned into two groups. The patients underwent bimaxillary surgery with computer-aided design and manufacturing cutting and drilling guides with prebent titanium plates (experimental group) or computer-aided design and manufacturing splints (control group). Preoperative and postoperative imaging data were collected and then analyzed using Mimics Research 19.0, Geomagic Studio, and IBM SPSS Version 21.0. RESULTS: Deformity evaluation and posttreatment assessment were performed for all patients. The experimental group had fewer postoperative complications. Comparison of the linear and angular differences to facial reference planes revealed more accurate repositioning of the mandible and condyles in the experimental group, although the position of several landmarks still requires small adjustments. CONCLUSION: Computer-aided design and manufacturing cutting and drilling guides with prebent titanium plates effectively corrected skeletal class III malocclusion, providing positional control of segments with reasonable surgical accuracy. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, II.


Asunto(s)
Diseño Asistido por Computadora , Maloclusión de Angle Clase III/cirugía , Procedimientos Quirúrgicos Ortognáticos/instrumentación , Osteotomía Le Fort/instrumentación , Cirugía Asistida por Computador/instrumentación , Adulto , Puntos Anatómicos de Referencia , Placas Óseas , Cefalometría/métodos , Femenino , Humanos , Imagenología Tridimensional , Masculino , Mandíbula/anatomía & histología , Mandíbula/diagnóstico por imagen , Mandíbula/cirugía , Maxilar/anatomía & histología , Maxilar/diagnóstico por imagen , Maxilar/cirugía , Procedimientos Quirúrgicos Ortognáticos/métodos , Osteotomía Le Fort/métodos , Estudios Prospectivos , Férulas (Fijadores) , Cirugía Asistida por Computador/métodos , Titanio , Tomografía Computarizada Espiral , Resultado del Tratamiento , Adulto Joven
18.
Sci Rep ; 10(1): 6793, 2020 04 22.
Artículo en Inglés | MEDLINE | ID: mdl-32322020

RESUMEN

An on-going debate concerning the dietary adaptations of archaic hominins and early Homo has been fuelled by contradictory inferences obtained using different methodologies. This work presents an extensive comparative sample of 30 extant primate species that was assembled to perform a morpho-functional comparison of these taxa with 12 models corresponding to eight fossil hominin species. Finite Element Analysis and Geometric Morphometrics were employed to analyse chewing biomechanics and mandible morphology to, firstly, establish the variation of this clade, secondly, relate stress and shape variables, and finally, to classify fossil individuals into broad ingesta related hardness categories using a support vector machine algorithm. Our results suggest that some hominins previously assigned as hard food consumers (e.g. the members of the Paranthropus clade) in fact seem to rely more strongly on soft foods, which is consistent with most recent studies using either microwear or stable isotope analyses. By analysing morphometric and stress results in the context of the comparative framework, we conclude that in the hominin clade there were probably no hard-food specialists. Nonetheless, the biomechanical ability to comminute harder items, if required as fallback option, adds to their strategy of increased flexibility.


Asunto(s)
Adaptación Fisiológica/fisiología , Dieta , Alimentos , Fósiles , Mandíbula/anatomía & histología , Masticación/fisiología , Animales , Evolución Biológica , Análisis de Elementos Finitos , Hominidae , Maxilares/anatomía & histología , Maxilares/fisiología , Mandíbula/fisiología , Primates/anatomía & histología , Primates/clasificación , Primates/fisiología , Cráneo/anatomía & histología , Cráneo/fisiología , Máquina de Vectores de Soporte
19.
J Appl Oral Sci ; 28: e20190399, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32348443

RESUMEN

Objectives To evaluate the acoustic properties of the /s/ sound in individuals with different occlusion types and to investigate relationships between these properties and cephalometric measurements. Methodology Sixty patients were divided into three groups based on malocclusion. Group 1 included 20 patients (mean age: 14.85±2.01 years) with Class I skeletal and dental relationships. Group 2 included 20 patients (mean age: 13.49±1.78 years) with Class II skeletal and dental relationships. Group 3 included 20 patients (mean age: 12.46±2.62 years) with Class III skeletal and dental relationships. Cephalometric tracings were obtained from cephalometric radiographs. All included patients were native speakers of Turkish. The /s/ sound was selected for center of gravity analysis. Correlations between cephalometric values and acoustic parameters were also investigated. Results The center of gravity of the /s/ sound had the lowest value in Group 2 (p<0.05). For the /s/ sound in Group 3, moderate positive correlations were found between center of gravity and Sella-Nasion to Gonion-Gnathion angle (p<0.05, r=0.444) Lower incisor to Nasion-B point (p<0.023, r=0.505), and Lower incisor to Nasion-B point angle (p<0.034; r=0.476). No correlation was found in other cephalometric measurements. Conclusions The /s/ sound was affected by malocclusion due to the changing place of articulation. Therefore, referral to an orthodontist for malocclusion treatment especially patients with class III in the early period is suggested for producing acoustically ideal sound.


Asunto(s)
Cefalometría , Maloclusión/fisiopatología , Acústica del Lenguaje , Trastornos del Habla/fisiopatología , Adolescente , Niño , Femenino , Humanos , Masculino , Maloclusión/complicaciones , Maloclusión/diagnóstico por imagen , Mandíbula/anatomía & histología , Mandíbula/fisiopatología , Maxilar/anatomía & histología , Maxilar/fisiopatología , Estudios Prospectivos , Radiografía , Valores de Referencia , Trastornos del Habla/diagnóstico por imagen , Trastornos del Habla/etiología , Estadísticas no Paramétricas , Lengua/anatomía & histología , Lengua/fisiopatología , Turquia
20.
Niger J Clin Pract ; 23(4): 534-538, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32246661

RESUMEN

Objectives: To study the prevalence of middle mesial and middle distal canals in permanent mandibular molars in Egyptian subpopulation using micro-computed tomography. Materials and Methods: Two hundred and forty extracted mandibular permanent molars of Egyptian patients were scanned using micro-computed tomography, then the images were reconstructed to allow for the detection of the middle mesial (MM) and middle distal (MD) canals of the molars examined. The path of each extra canal was studied to determine the configuration of each canal. Data were analyzed statistically using the Chi-square test with a level of significance set at P< 0.05. Results: The evaluation of three-dimensional (3D) images of this study showed that no significant difference was found between the percentage of MM (27.5%) and MD canals (22.5%) (P = 0.2064); however, there was a significant difference between the percentage of teeth having both extra canals (10%) and teeth having only one of these canals (P < 0.05). The confluent configuration (71%) was significantly higher than the other configurations (P < 0.05). Conclusion: A higher percentage of MM canal was detected followed by the MD canal. The least significant was both canals occurring within the same molar. The percentage of the confluent configuration was the highest. The apt knowledge of the variations of the root canal system anatomy and the respect of the discrepancies associated with diverse demographic areas will ensure the proper management of each tooth with endodontic involvement and its long-term success.


Asunto(s)
Diente Molar/anatomía & histología , Tratamiento del Conducto Radicular , Raíz del Diente/anatomía & histología , Estudios Transversales , Egipto/epidemiología , Humanos , Mandíbula/anatomía & histología , Tratamiento del Conducto Radicular/efectos adversos , Tratamiento del Conducto Radicular/estadística & datos numéricos
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