497 research outputs found

    CAMBIAMENTI TRIDIMENSIONALI DEL MASCELLARE SUPERIOREDOPO ESPANSIONE CON LEAF EXPANDER® IN UN CAMPIONEDI PAZIENTI IN ETA¿ EVOLUTIVA.VALUTAZIONE MEDIANTE SOVRAPPOSIZIONE DI MODELLI DIGITALI E DI CTBC

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    Scopo del lavoro: valutare le modificazioni trasversali delle arcate ottenuti con un\u2019espansione lenta, con forze leggere ed alto controllo del movimento, su un campione di pazienti in crescita, con insufficienza trasversale del mascellare. Materiali e Metodi: sono stati inclusi nello studio n\ub0 10 pazienti (n\ub0 3 maschi, n\ub0 7 femmine) con un\u2019et\ue0 media di 7 anni 5 mesi +/- 7 mesi, trattati con espansione mascellare lenta per la correzione di crossbite posteriore monolaterale (con shift mandibolare), mediante il dispositivo denominato Leaf Expander (L.E.), ancorato sui secondi molari decidui. Su questo campione di n\ub010 pazienti sono stati eseguiti due diversi Studi Pilota. - Studio Pilota I In tutti i pazienti (n\ub010) sono stati realizzati modelli digitali delle arcate dentarie prima dell\u2019inizio del trattamento (T1) e a fine terapia, al momento della rimozione dell\u2019espansore L.E. (T2). I modelli sono stati analizzati rilevando n\ub05 parametri lineari: 1) distanza intermolare sup. (molari permanenti) 2) distanza intermolare sup. (molari decidui) 3) distanza intercanina superiore 4) distanza intermolare inferiore (molari permanenti) 5) distanza intercanina inferiore - Studio Pilota II In n\ub0 5 pazienti, con deficit di spazio a carico dei canini superiori, \ue8 stata effettuata una tomografia computerizzata cone beam (CBCT) prima dell\u2019inizio del trattamento (T1), seguita da una CBCT al momento della rimozione del L.E. (T2). Sono state eseguite misurazioni e sovrapposizioni al fine di valutare n\ub0 3 parametri, i pi\uf9 significativi secondo la letteratura: 1) ampiezza nasale 2) ampiezza mascellare a livello dei II molari decidui 3) ampiezza mascellare a livello di primi molari permanenti Risultati: In tutti i pazienti si \ue8 realizzata la correzione del crossbite posteriore, con 4 mesi di trattamento in media. Tutti i parametri oggetto di valutazione, dentali e scheletrici, relativi all\u2019arcata superiore, sono aumentati significativamente durante la fase di espansione lenta mascellare. Il percorso eruttivo e la prognosi dei canini inclusi risultano migliorati. Per quanto riguarda l\u2019arcata mandibolare abbiamo rilevato la riduzione del diametro intermolare 6-6 e l\u2019incremento del diametro intercanino. Conclusioni: i risultati dei due Studi Pilota convalidano l\u2019efficacia dell\u2019espansore lento Leaf Expander, nel trattamento delle insufficienze trasversali del mascellare, nel giovane paziente, con azione sia dentoalveolare sia scheletrica.Aim of the researche: The purpose of this study was to evaluate and compare the dental and bone effects of slow maxillary expansion, with low forces and hight movement control, in a sample of young patients with unilateral transversal maxillary deficiency, with mandibular shift. Materials and method: have been included in the study 10 patients (n\ub0 3 male, n\ub0 7 female) with an average age of 7.5 yrs +/- 7, treated with a slow maxillary expansion by Leaf Expander appliance . - Pilot Study I: for all ten patients, the digital models have been made at the beginning of the therapy (T1), at the end of expansion (T2). Five parameters have been measured with the cast analysis: 1) the distance between the first upper permanent molars 2) the distance between the upper second deciduous molars 3) the distance between the upper canine cusps 4) the distance between the lowers molars 5) the distance of the lower canine cusps. - Pilot Study II: for only 5 patients, with loss of space for upper cusps, a cone beam computed tomography (CBCT) have been performed at the beginning of the therapy (T1) and after expansion (L.E. remotion) (T2). Misurations and superimpositions have been performed to evaluate the three parameters, most relevant on basis of literature: 1) nasal width 2) basal bone 3) intermolar diameter at II deciduous molars Results: In all the patients the complete correction of posterior crossbite has been achieved in 4 monts, on average. Significant increases in the dental and skeletal transversal diameters were obtained with slow maxillary expansion. Increases were also obtained about anterior mandibular arch (+ 1mm). Conclusions: the Pilot Studys performed confirm the soundness of Leaf Expander appliance in the transversal deficiency correction with a both dental-alveolar and skelectal action in the treatment of young patients

    Three-dimensional evaluation of rapid maxillary expansion anchored to primary molars: Direct effects on maxillary arch and spontaneous mandibular response

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    Aim The purpose of this study was to evaluate the effects of rapid maxillary expansion (RME) on maxillary and mandibular arch in the mixed dentition. Methods Forty-four consecutive patients with transverse maxillary deficiency were recruited. Test group: 21 patients (10 male, 11 female; 7.4 \ub1 1.2 years) who underwent RME (Haas type) therapy banded on the primary second molars. Control group: 17 patients (10 male, 7 female; 7.3 \ub1 1.1 years old) who did not receive any orthodontic treatment. Dental casts obtained pre-treatment and after appliance removal (11 months) were processed by means of a three-dimensional scanner (3Shape D250 laser, DK). Digital landmarks were traced using the VAM software (Canfield Scientific Inc., Fairfield-NJ, USA). Arch Length, interdental width and torque differences were measured before and after the removal of the appliance. The t-test (P < 0.05) for paired data was applied to evaluate the measurements values before and after treatment. The linear regression model was employed to assess the correlations between treatment effects. Results The efficacy of the RME was confirmed both on maxillary and mandibular arch. Mandibular intermolar width (+2.02 mm) together with primary intermolar (+1.39 mm), intercanine width (+0.95mm) and torque variations significantly increased. The untreated control group showed no significant statistical differences between T0 and T1. The linear regression between maxillary and mandibular data showed correlations between the torque of the teeth 16/46 and 65/85 (P < 0.05). Conclusions RME anchored on primary molars is an effective treatment option to correct tranverse maxillary deficiencies. All the measurements increased significantly confirming the indirect effect of RME on the mandibular arch

    A Domain Decomposition Approach to Finite Volume Solutions of the Euler Equations on Triangular Meshes

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    we report on our recent efforts on the formulation and the evaluation of a domain decomposition algorithm for the parallel solution of two-dimension- al compressible inviscid flows. The starting point is a flow solver for the Euler equations which is based on a combined finite element/finite volume formulation on unstructured triangular meshes for the spatial discretiz- ation. Time integration of the resulting semi-discrete equations is obtained using a linearized backward Euler implicit scheme. As a result, each pseudo time step requires the solution of a sparse linear system for the flow variables. In this study, a non-overlapping domain decomposition algorithm is used for advancing the solution at each implicit time step. First, we formulate an additive Schwarz algorithm using appropriate matching conditions at the subdomain interfaces. In accordance with the hyperbolic nature of the Euler equations, these transmission conditions are Dirichlet conditions for the characteristic variables corresponding to incoming waves. Then, we introduce interface operators that allow to express the domain decomposition algorithm as a Richardson type iteration on the interface unknowns. Algebraically speaking, the Schwarz algorithm is equivalent to a Jacobi iteration applied to a linear system whose matrix has a block structure. A substructuring technique can be applied to this matrix in order to obtain a fully implicit scheme in terms of interface unknowns. In our approach, the interface unknowns are numerical (normal) fluxes

    A Non-Overlapping Domain Decomposition Method for Solving the Navier-Stokes Equations on Unstructured Triangular Meshes

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    we report on our recent efforts on the formulation and the evaluation of a non-overlapping domain decomposition method for the parallel solution of two-dimensional compressible viscous flows. This work extends a previous study [11] which was concerned with the design of a domain decomposition solver for the Euler equations discretized on unstructured triangular meshes. As in [11], the method relies on the formulation of an additive Schwarz type algorithm where the interface conditions express the continuity of the normal flux components. The starting point is a flow solver for the Navier-Stokes equations which is based on a combined finite element/finite volume formulation on unstructured triangular meshes for the spatial approxima- tion. Time integration of the resulting semi-discrete equations is performed by using a linearized backward Euler implicite scheme. As a result, each pseudo time step requires the solution of a sparse linear system for the flow variables. In this study, a non-overlapping domain decomposition algorithm is used for advancing the solution at each implicit time step. Algebraically speaking, the Schwarz algorithm is equivalent to a Jacobi iteration applied to a linear system whose matrix has a block structure. A substructuring technique can be applied to this matrix in order to obtain a fully implicit scheme in terms of interface unknowns. In our approach, the interface unknowns are numerical fluxes

    Out of the forest: past and present range expansion of a parthenogenetic weevil pest, or how to colonize the world successfully

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    Previous research revealed complex diversification patterns in the parthenogenetic weevil Naupactus cervinus. To understand the origin of clonal diversity and successful spreading of this weevil, we investigated its geographic origin and possible dispersal routes and whether parthenogens can persist in habitats under unsuitable environmental conditions. This study is based on samples taken throughout a broad area of the species’ range. We used both mitochondrial and nuclear markers and applied phylogenetic and network analyses to infer possible relationships between haplotypes. Bayesian phylogeographic analyses and ecological niche modeling were used to investigate the processes that shaped genetic diversity and enabled the colonization of new geographic areas. Southeastern Brazil emerges as the original distribution area of N. cervinus. We detected two range expansions, one along natural corridors during the Pleistocene and the other in countries outside South America during recent times. Isolation due to climate shifts during the early Pleistocene led to diversification in two divergent clades, which probably survived in different refugia of the Paranaense Forest and the Paraná River delta. The origin of the clonal diversity was probably a complex process including mutational diversification, hybridization, and secondary colonization. The establishment of N. cervinus in areas outside its native range may indicate adaptation to drier and cooler conditions. Parthenogenesis would be advantageous for the colonization of new environments by preventing the breakup of successful gene combinations. As in other insect pests, the present distribution of N. cervinus results from both its evolutionary history and its recent history related to human activities.Facultad de Ciencias Naturales y Muse

    Effects On Palatal Surface Area In Mixed Dentition Patients Treated With Leaf Expander And Rapid Palatal Expander, Compared To Untreated Subjects: A Randomised Clinical Trial

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    Aim: To evaluate palatal surface effects induced by LE and RPE, alongside spontaneous changes in an untreated group, and to compare differences in canine and molar inclination among the three groups. Materials and Methods: This randomised clinical trial aimed to compare digital models pre- and post-treatment over 12 months in patients receiving tooth-borne Leaf Expander® (LE) and tooth-borne Hyrax-type maxillary expander (RPE) treatments, alongside untreated patients. Analysis included 24 LE patients (13 males, 11 females, mean age 8.5±1.5), 22 RPE patients (10 males, 12 females, mean age 7.9±1.6), and 17 untreated subjects (7 males, 10 females, mean age 8.1±1.2). Inclusion criteria comprised indications for maxillary expansion treatment, mixed dentition, CVMS ≤ 3, erupted first molars, and good oral hygiene. Digital models were obtained using an intraoral scanner pre- and post-treatment. Palatal surface, segmented into anterior, median, and posterior zones, and canine/molar inclination were measured at T0-T1 using VAM software as the primary and secondary endpoint. Statistical analyses involved paired-sample T-tests for intra-group comparisons and ANOVA tests with Bonferroni correction for inter-group comparisons. Results: Total surface increment for LE was 155.4 mm2 (±49.92mm2); for RPE, it was 187.7 mm2 (±58.06 mm2); and for the control group, it was 55.35 mm2 (±18.69mm2), significant in all three groups. Statistically significant differences were observed in the anterior, median, and posterior zones, as well as in the total surface increment, between the LE and control groups, and between the RPE and control groups. No significant difference was found between the LE and RPE groups in surface increments. The RPE group exhibited a significant increase in vestibular inclination for molars and canines post-therapy. Conclusions: No significant difference in palatal surface increment was found between the two experimental groups (LE and RPE); both demonstrated a significant increase in palatal surface. The greatest increment occurred in the median palate zone for both experimental groups. The increment in the untreated control group was not significant. Furthermore, the RPE group showed a greater inclination of permanent molars compared to those treated with LE, indicating that expansion with lighter and continuous forces may lead to fewer dental side effects

    Phylogenetic analysis of the Pantomorus-Naupactus complex (Coleoptera: Curculionidae: Entiminae) from North and Central America

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    We undertook the first cladistic analysis of the Pantomorus-Naupactus complex (Coleoptera: Curculionidae) from North and Central America, based on 35 species and 61 morphological characters, plus 1151 bp of the mtDNA COI and Cyt b genes. The morphological and the combined matrices analyzed with TNT yielded a single most parsimonious cladogram that allows recognition of two main lineages within the Pantomorus-Naupactus complex in North and Central America. One is represented by the species formerly placed in Phacepholis and the Pantomorus species group II sensu Sharp, ranging along the Pacific coast of Central America and Mexico and reaching the Great Plains of North America in the United States, yet not occurring in South America. The other lineage is represented by the species of Naupactus and Pantomorus: species group I, with closer relationships to the South American species of these genera. The Pantomorus group I includes the type species of the genus P. albosignatus Boheman whereas the Pantomorus group II includes the type species of Athetetes Pascoe, 1886 (A. globicollis Pascoe). Based on the results of our phylogenetic analysis, we recommend retaining the name Pantomorus Schoenherr for most species of the Pantomorus group I, except P. stupidus (Boheman) and P. femoratus Sharp which should be transferred to Naupactus Dejean. Moreover, we enlarge the previous concept of Phacepholis to include most species of the Pantomorus group II, and we establish the synonymy of Athetetes Pascoe, 1886 with Phacepholis Horn, 1876, being the latter the valid name, by priority.We undertook the first cladistic analysis of the Pantomorus-Naupactus complex (Coleoptera: Curculionidae) from North and Central America, based on 35 species and 61 morphological characters, plus 1151 bp of the mtDNA COI and Cyt b genes. The morphological and the combined matrices analyzed with TNT yielded a single most parsimonious cladogram that allows recognition of two main lineages within the Pantomorus-Naupactus complex in North and Central America. One is represented by the species formerly placed in Phacepholis and the Pantomorus species group II sensu Sharp, ranging along the Pacific coast of Central America and Mexico and reaching the Great Plains of North America in the United States, yet not occurring in South America. The other lineage is represented by the species of Naupactus and Pantomorus: species group I, with closer relationships to the South American species of these genera. The Pantomorus group I includes the type species of the genus P. albosignatus Boheman whereas the Pantomorus group II includes the type species of Athetetes Pascoe, 1886 (A. globicollis Pascoe). Based on the results of our phylogenetic analysis, we recommend retaining the name Pantomorus Schoenherr for most species of the Pantomorus group I, except P. stupidus (Boheman) and P. femoratus Sharp which should be transferred to Naupactus Dejean. Moreover, we enlarge the previous concept of Phacepholis to include most species of the Pantomorus group II, and we establish the synonymy of Athetetes Pascoe, 1886 with Phacepholis Horn, 1876, being the latter the valid name, by priority.Fil: Rosas, María V.. Universidad Nacional Autónoma de México; MéxicoFil: Morrone, Juan José. Universidad Nacional Autónoma de México; MéxicoFil: del Rio, Maria Guadalupe. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Lanteri, Analia Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentin

    A CBCT based analysis of the correlation between volumetric morphology of the frontal sinuses and the facial growth pattern in caucasian subjects. A cross-sectional study

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    open7noBackground: The aim of this study was to evaluate the relationship between frontal sinus shape and facial growth pattern. Methods: The three-dimensional examination was carried out by means of 80 CBCT scans selected from a sample of 1247 records of patients treated, for different reason, at the Department of Biomedical Surgical and Dental Sciences at University of Milan, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico Milan. The sample (age ranges between 12 and 40 years) was divided according to gender and age in four groups (12-17, 18-20, 21-30, 31-40). Left and right frontal sinus volume (VOL), surface (SUP) and linear maximum width (XMAX), depth (ZMAX) and height (YMAX) were calculated using Mimics Research 17.0 (Materialise N.V., Leuven, Belgium). Cephalometric analysis has been performed for all subjects to categorize the patients depending on their facial growth pattern. Univariate and multivariate regression analysis were performed to investigate any association of frontal sinuses measurements (height, width, depth, volume and surface) and cephalometric variables. P value < 0.05 was considered statistically significant. Results: A total of 160 frontal sinuses were measures in 80 patients: 40 men and 40 women, average age of 23.5 ±14.6. Globally the frontal sinuses had the following average dimensions: volumes of 9055.8 ± 6505 mm3 and surfaces of 3820.3 ± 2125 mm2. The statistical analysis showed that frontal sinus volume was statistically significant (p=0.003) greater for male (11,425 mm3) than female (6597.5 mm3). Similarly, the surface showed to be greater in men than in women (p=0.005). No correlation between age and frontal sinuses characteristics has been found. A statistically significant (p<0.05) increase of frontal sinus depth, surface and volume was correlated with SNB angle. In addition, frontal sinus volume increased in subjects with greater anterior skeletal dimension values and with a superior length of the cranial base. Furthermore, a decrease of ANB has been found related to an increase in frontal sinus volume (p=0.04). Conclusions: The present study showed a correlation between frontal sinuses dimensions and craniofacial aspects, despite the inter-individual variability of their morphology. The results suggested that young adults in whom the frontal sinuses have reached their maximum size, while vertical growth continues, a larger frontal sinus may be associated with future vertical growth.openAbate A.; Gaffuri F.; Lanteri V.; Fama A.; Ugolini A.; Mannina L.; Maspero C.Abate, A.; Gaffuri, F.; Lanteri, V.; Fama, A.; Ugolini, A.; Mannina, L.; Maspero, C

    Correlation between dental vestibular-palatal inclination and alveolar bone remodeling after orthodontic treatment: A CBCT analysis

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    The aim of this study was to evaluate the correlation between dental vestibular-palatal inclination changes and the cortical bone remodeling after fixed orthodontic treatment using cone beam computed tomography (CBCT). Twenty-two patients with Angle Class I malocclusion, permanent dentition, and mild to moderate dental crowding were included in the present three-dimensional (3D) analysis. Bone dimensions were evaluated by CBCT scans obtained before and after orthodontic treatment, whereas the torque values were calculated by means of digital models using the 3D VistaDent software. A paired t-test was used to compare the changes between the pretreatment and post-treatment measurements. The correlations between variables were analyzed with linear regression analysis. A significant correlation between torque variations and bone thickness changes was observed for the apical buccal level of the anterior side (P < 0.05). Limited and not significant alveolar bone resorption for the apical thickness of anterior teeth occurred at \ub15 degrees of torque variation, while for tooth inclination exceeding +5 or-5 degrees, the bone remodeling was more evident. The present study demonstrated that anterior region was the most affected area by bone remodeling and that torque variation was highly related to apical bone thickness adaptation for maxillary and mandibular incisors and maxillary canines
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