Comparative photoelastic analysis of the dental and skeletal anchorage used in the surgically assisted rapid maxillary expansion

Orientadores: Luciana Asprino, Marcio de MoraesTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: A expansão rápida de maxila cirurgicamente assistida é um método eficiente no tratamento da deficiência transversa da maxila em paciente adultos. O objetivo deste estudo mecânico qualitativo foi avaliar por meio de modelos fotoelásticos de um crânio humano a simulação da expansão rápida de maxila cirurgicamente assistida, comparando três tipos de ancoragem, analisando a distribuição de forças, com e sem disjunção ptérigomaxilar. As ancoragens utilizadas foram: um expansor Hyrax com ancoragem em primeiros pré?molares e primeiros molares; um expansor chamado de Hyrax modificado, com bandas em primeiros pré?molares e primeiros molares unidos a um fio ortodôntico retangular que se estendia de caninos a segundo molar; e ancoragem óssea do distrator de Rotterdam. A análise fotoelástica qualitativa foi realizada utilizando?se polariscópio plano. Os três expansores apresentaram distribuição de tensões homogêneas pelas réplicas de crânio através dos pilares caninos, pilares zigomáticos e processos pterigóideos, se estendendo para regiões mais altas do crânio; O expansor Hyrax modificado apresentou melhor distribuição das tensões nos dentes e adjacências, com menor concentração nessa região que o expansor Hyrax. A ancoragem promovida pelo distrator de Rotterdam apresentou melhor distribuição das tensões com menor concentração nos dentes e adjacências do que os expansores Hyrax e Hyrax modificado. Após a simulação das osteotomias, ocorreu marcante diminuição de forças para as regiões superiores das réplicas de crânio. Em conclusão: A ancoragem promovida pelo expansor Hyrax modificado apresentou melhor distribuição das tensões com menor concentração das mesmas nos dentes e adjacências do que o expansor Hyrax; A ancoragem promovida pelo expansor Rotterdam apresentou melhor distribuição das tensões com menor concentração das mesmas nos dentes e adjacências do que os expansores Hyrax e Hyrax modificado; A realização da disjunção ptérigomaxilar resultou em diminuição da concentração de tensões pelo crânio independente da ancoragem avaliadaAbstract: The Surgically Assisted Rapid Maxillary Expansion (SARME) is an efficient method to treat the transverse maxillary deficiency. The aim of this mechanical and qualitative study was to evaluate the distribution of stress throughout the skull, of three different expanders used in the surgically assisted rapid maxillary expansion (SARME), using comparative photoelastic analysis simulating SARME with and without pterygoidmaxillary disjunction. The skull analogs were constructed in two halves, to allow the creation of nasal cavity and maxillary sinuses, which were subsequently bonded. It was used three different expanders in the tests. The first was a standard Hyrax-type appliance, with anchorage at first bicuspids and first molars. The second was a modified Hyrax-type appliance, with anchorage at first bicuspids and first molars that was united by means of a passively adapted rectangular orthodontic wire splinting together cuspid, bicuspid first and second molars. The third was the bone-borne Rotterdam expander. The photoelastic analysis was done immerging the skull replicas in a tank of mineral oil and using a plane polariscope. All three expanders generated similar anterior and posterior fringe patterns along the canine and zygomatic buttress and pterigoid processes. The modified hyrax showed a wider distribution of the tension through the teeth, with a decrease intensity of the fringe patterns when compared with the Hyrax expander. The Rotterdam distractor did not showed tension lines at and around the teeth, resulting in better force distribution than the two others expanders. The simulation of the osteotomies of the SARME decreased the amount of fringe patterns throughout the skull analogs. In conclusion, the three anchorage evaluated did not influence the final distribution of tension throughout the skull; there were variation in the fringe patterns generated by different anchorages; the modified Hyrax-type appliance indicates less load over teeth than the conventional Hyrx-type; the Rotterdam distractor does not load teeth, keeping the patterns of force distribution in the skull analog; the pterigomaxillary disjunction makes the SARME easier and predictable, independently of the anchorage usedDoutoradoCirurgia e Traumatologia Buco-Maxilo-FaciaisDoutor em Clínica Odontológic

Photoelastic evaluation of the surgically assisted rapid maxilary expansion using different othodontic anchorages

Orientadores: Luciana Asprino, Marcio de MoraesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O objetivo deste estudo foi avaliar por meio de modelos fotoelásticos de um crânio humano a expansão da maxila cirurgicamente assistida, comparando diferentes aparelhos e ancoragens ortodônticas para expansão e sua distribuição de forças, com e sem disjunção ptérigomaxilar. Foram utilizados nos testes seis aparelhos diferentes. Três Hyrax, um com ancoragem em primeiros pré-molares e primeiros molares (H1), um com ancoragem em caninos e primeiros molares (H2) e um com ancoragem em caninos e segundos molares (H3) e três aparelhos Haas (A1, A2, A3) com as três ancoragens citadas acima. Estes aparelhos foram submetidos a um teste de carga previamente a análise fotoelástica. Os testes de carga mostraram que todos os aparelhos avaliados produziram forças ortopédicas (> 500 gramas). A análise fotoelástica revelou que os aparelhos Haas apresentam distribuição de tensões mais homogêneas pela maxila; Os aparelhos com ancoragem em primeiros pré-molares e primeiros molares geram maior concentração de tensões na região posterior da maxila; A separação dos processos pterigóideos, em todos os seis crânios avaliados, mostrou diminuição das tensões com menor concentração das tensões por todo o esqueleto facial. Em conclusão, os aparelhos Haas apresentaram melhor distribuição das tensões com menor concentração das mesmas nos dentes e adjacências do que o aparelho Hyrax; as variações de ancoragem ortodôntica não apresentaram diferenças significativas; e todos os pilares de resistência, inclusive os processos pterigóideos, devem ser separados da maxila para evitar efeitos indesejáveis de acúmulo de tensões no restante das estruturas do crânio.Abstract: The aim of this study was to evaluate how variations in the design of the orthodontic appliances and their anchorages would influence the distribution of forces along the cranial bones through a photoelastic skull model during the surgically assisted maxillary expansion with and without pterygoid splitting. It was used six different expanders in the tests. Three of them were Hyrax aplliances, with anchorage at first bicuspids and first molars (H1), canines and first molars (H2) and canines and second molars (H3). The three Haas appliances had the same anchorage patterns described above (A1, A2, A3). The three Haas appliances were submitted to a load peak test to evaluate the forces in the orthopedic range (> 500 grams). The photoelastic analysis revealed that Haas expanders generated similar anterior and posterior fringe patterns, while anchorage at first bicuspids and first molars created stress at the posterior region of the maxilla. The splitting of the pterygoid plates lowered the tension necessary for SARME. In conclusion, Haas expanders showed better distribution of tension lines in the maxilla, without higher concentration of tension in and around the teeth; variation on the anchorage does not influence the final result and release of all anatomic resistance, including pterygoid plates splitting facilitates the expansion movement.MestradoCirurgia e Traumatologia Buco-Maxilo-FaciaisMestre em Clínica Odontológic

Analysis of 185 maxillofacial fractures in the state of Santa Catarina, Brazil

A retrospective study was performed to assess maxillofacial fractures in patients treated at a public hospital from 2002 to 2006. The data collected included age, gender, etiology, type of injury, treatment modalities and period of treatment. Causes were grouped into seven categories: road traffic collisions, sports accidents, occupational accidents, gunshot fractures, falls, violence and other causes. The analyses involved descriptive statistics, the Chi-squared Test and the Fisher Exact Test. Records from 132 patients sustaining 185 maxillofacial fractures were evaluated. The mandible (54.6%) was the most commonly fractured bone in the facial skeleton, followed by the zygoma (27.6%). The mean age of the patients was 37.7 years, and the male:female ratio was 4.3:1. Most fractures occurred in adults with ages ranging from 18 to 39 years. A significant statistical relation was found between the age and the etiology of the trauma (p < 0.05), and between the number of fractured sites and the age of the patient (p < 0.05). Considering the age groups, accidents were the most frequent cause of maxillofacial fractures in the age group between 18 to 39 years, and interpersonal violence was the most frequent cause of maxillofacial fractures in the age group between 40 to 59 years. Treatment was performed on the same day as the diagnosis in 44.7% of the patients. Open surgery with internal stable fixation was indicated for most of the patients. Facial fractures occurred primarily among men under 30 years of age, and the most common sites of fractures in the face were the mandible and the zygomatic complex. Traffic road collisions were the main etiologic factor associated with maxillofacial trauma

A Comparison Of Motorcycle And Bicycle Accidents In Oral And Maxillofacial Trauma.

The aim of this study was to present a large series of motorcycle- and bicycle-related traumas to the face in an attempt to identify the injury pattern in motorcyclists and bicyclists. Data were collected from patients during a 10-year period (1999 through 2009), which included demographic data, diagnosis of facial fractures, use of protective devices, dentoalveolar trauma, and facial soft tissue injuries. There were 556 patients with bicycle accidents and 367 with motorcycle accidents. Men were involved in 79% (436) of bicycles accidents and 82% (299) of motorcycle accidents. Young male patients were more frequent in bicycle and motorcycle accidents. Two hundred fifty bicyclists showed 311 maxillofacial fractures. Two hundred twenty-one motorcyclists showed 338 maxillofacial fractures. Motorcycle accidents caused multiple fractures in more patients. Seventy-six percent of motorcyclists were using helmets at the time of the accidents, whereas 6% of cyclists were using helmets. Motorcyclists showed a larger number of lacerations, whereas bicyclists showed a larger number of abrasions. Avulsion was the most common dentoalveolar injury for these accident types. Hospital stays were 3.8 days for motorcyclists and 1.3 days for bicyclists. The high-impact collisions typically observed in motorcycle accidents is directly related to larger percentages of soft tissue lacerations and facial fractures. The low-impact trauma that is observed in bicycle accidents is more commonly associated with soft tissue abrasion, hematoma, and dentoalveolar fractures. This stresses the need for compulsory legislation for helmet use with face-guards for cyclists and motorcyclists. It is important to take measures to alert the public regarding the severity of injuries likely to occur in bicycle- and motorcycle-related accidents and ways to prevent them.70577-8

Existem válvulas na veia femoral em ratas Wistar?

Resumo As veias femorais de 30 ratas da linhagem Wistar foram estudadas por método histológico com objetivo de investigar a presença de válvulas. Na análise histológica não foram identificadas projeções do endotélio ou recessos valvares que poderiam sugerir a presença de válvulas venosas nessa espécie de animal

Ballistic Performance of Mallow and Jute Natural Fabrics Reinforced Epoxy Composites in Multilayered Armor

<div><p>Natural fiber reinforced polymer composites have recently been investigated as a component of multilayered armor system (MAS). These composites were found to present advantages when replacing conventional high strength synthetic aramid fabric laminate composite (KevlarTM, with same thickness, as MAS second layer. Continuous and loose natural fibers were up to now mostly used to reinforce these ballistic composites. Only two natural fabrics reinforced polymer composite were so far used with same purpose. Therefore, this work investigated the possibility of substituting KevlarTM for three other natural fabrics, based on mallow and jute fibers, as reinforcement of epoxy composites. Fabrics made of either pure mallow, or 70%mallow/30% jute or 50%mallow/50% jute fibers were separately mixed with epoxy to produce laminate composite plates. These plates were set as second layer of Al2O3/Nb2O5 front ceramic MAS, that were ballistic tested against relatively high energy 7.62 mm ammunition. Indentation depth values caused by the bullet penetration in clay witness, simulating human body behind the MAS, were always found to be below the safety standard limit. These indentation values were similar to those obtained in MAS with KevlarTM as second layer. However, significant economical advantages favor the investigated natural fabric composites over the synthetic Kevlar.</p></div

Treatment of condylar fractures with an intraoral approach using an angulated screwdriver: Results of a multicentre study

Background This multicentre study aimed to investigate long-term radiographic and functional results following the treatment of condylar fractures using an angulated screwdriver system and open rigid internal fixation with an intraoral surgical approach. Methods Twenty-nine patients with a total of 32 condylar fractures were evaluated. The patients were investigated prospectively based on the following variables: age, sex, aetiology, side, location and classification of the fracture, degree of displacement, associated fractures, surgical approach, oral health status, type of osteosynthesis plate, duration of surgery, mouth-opening, complications, and duration of follow-up. Results The fractures were classified as subcondylar (n = 25) or condylar neck (n = 7). Mean patient age was 36.38 ± 16.60 years. The median duration of postoperative follow-up was 24.39 ± 13.94 months. No joint noise, weakness of the facial nerve, joint pain, or muscle pain was observed. An additional retromandibular approach was necessary to enable the treatment of one subcondylar fracture with medial displacement. Conclusion Subcondylar or condylar neck fractures with medial or lateral displacement can be treated using an intraoral approach with satisfactory results with the advantages of the absence of visible scarring, the avoidance of facial nerve injury, and the ability to obtain rapid access to the fracture