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Ciocanel, Despina E. "Atlantoaxial instability : biomechanical evaluation of T-Plate versus transarticular screw fixation." Connect to full-text via OhioLINK ETD Center, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=mco1116798081.
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Thesis (M.S.)--Medical College of Ohio, 2005.<br>"In partial fulfillment of the requirements for the degree of Master of Science in Biomedical Sciences." Major advisor: Nabil Ebraheim. Includes abstract. Document formatted into pages: iii, 57 p. Title from title page of PDF document. Bibliography: pages 35-42,49-56.
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Desai, Krishna P. "A Biomechanical Comparison of Locking Compression Plate Constructs with Plugs/Screws in Osteoporotic Bone Model." Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1271706065.
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Mayo, Andrew. "A biomechanical study of top screw pullout in anterior scoliosis correction constructs." Thesis, Queensland University of Technology, 2007. https://eprints.qut.edu.au/17152/1/Andrew_Elton_Mayo_Thesis.pdf.
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Top screw pullout is a significant problem in anterior scoliosis correction, with rates of 5-15% reported in the literature. The Mater Misericordiae Hospital in Brisbane currently has a series of 125 patients with scoliosis treated by thoracoscopic anterior fusion, instrumentation and correction between April 2000 and August 2007. In this series 11 top screws are known to have pulled out (a rate of 8.8%), with six occurring in the first week, and all within 6 weeks, suggesting that the problem is one of excessive static force rather than fatigue.
This thesis describes a biomechanical investigation into the mechanics of vertebral body screw pullout in anterior scoliosis surgical constructs. Previous biomechanical studies of vertebral body screws have evaluated their resistance to either straight pullout or cephalo-caudad compression forces, however the aim of this study was to assess screw resistance to more realistic loading conditions, namely pullout of initially angled screws, and pullout where the motion path is an arc rather than a straight axial pullout, as would be expected in a single rod anterior construct.
The first series of experiments involved straight and angled pullout tests using synthetic bone. In the angled tests, both locked and free-to-pivot configurations were tested. The second series of experiments tested the effect of cephalo-caudad pre-compression (the actual deformity correction step performed during surgery) on subsequent axial pullout strength. A third series of experiments performed arc pullouts using synthetic bone, and the final series of experiments tested the pullout resistance of a newly proposed screw position configuration against the standard screw positioning using ovine lumbar vertebrae.
Synthetic bone testing revealed that for initially angled pullout, resistance is greatest as the screw angle approaches 0 (ie a direct axial pullout). Cephalo-caudad pre-compression reduced subsequent pullout strength for cases where a staple was not used under the screw head, but if a staple was used the pre-compression did not decrease pullout force significantly. Arc pullout resistance was greatest when the screw was angled at 10 cephalad, and the mean pullout strength for the proposed screw configuration using ovine lumbar vertebrae (1864N) was almost double that of the standard screw positioning (993N).
The clinical implication of this study is that top screw pullout resistance can be maximised by placing the top screw as close as possible to the top endplate and the bottom screw as close as possible to the bottom endplate, although this will have detrimental effects on the pullout of the second screw should the top screw pull out. Screw angulation is a less important factor but any angulation should be in a cephalad direction and around 10º in magnitude. The experimental results also suggest that the use of a staple may play a role in preventing cephalo-caudad pre-compression forces from reducing screw resistance to subsequent pullout forces.
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Mayo, Andrew. "A biomechanical study of top screw pullout in anterior scoliosis correction constructs." Queensland University of Technology, 2007. http://eprints.qut.edu.au/17152/.
Full textAbstract:
Top screw pullout is a significant problem in anterior scoliosis correction, with rates of 5-15% reported in the literature. The Mater Misericordiae Hospital in Brisbane currently has a series of 125 patients with scoliosis treated by thoracoscopic anterior fusion, instrumentation and correction between April 2000 and August 2007. In this series 11 top screws are known to have pulled out (a rate of 8.8%), with six occurring in the first week, and all within 6 weeks, suggesting that the problem is one of excessive static force rather than fatigue.
This thesis describes a biomechanical investigation into the mechanics of vertebral body screw pullout in anterior scoliosis surgical constructs. Previous biomechanical studies of vertebral body screws have evaluated their resistance to either straight pullout or cephalo-caudad compression forces, however the aim of this study was to assess screw resistance to more realistic loading conditions, namely pullout of initially angled screws, and pullout where the motion path is an arc rather than a straight axial pullout, as would be expected in a single rod anterior construct.
The first series of experiments involved straight and angled pullout tests using synthetic bone. In the angled tests, both locked and free-to-pivot configurations were tested. The second series of experiments tested the effect of cephalo-caudad pre-compression (the actual deformity correction step performed during surgery) on subsequent axial pullout strength. A third series of experiments performed arc pullouts using synthetic bone, and the final series of experiments tested the pullout resistance of a newly proposed screw position configuration against the standard screw positioning using ovine lumbar vertebrae.
Synthetic bone testing revealed that for initially angled pullout, resistance is greatest as the screw angle approaches 0 (ie a direct axial pullout). Cephalo-caudad pre-compression reduced subsequent pullout strength for cases where a staple was not used under the screw head, but if a staple was used the pre-compression did not decrease pullout force significantly. Arc pullout resistance was greatest when the screw was angled at 10 cephalad, and the mean pullout strength for the proposed screw configuration using ovine lumbar vertebrae (1864N) was almost double that of the standard screw positioning (993N).
The clinical implication of this study is that top screw pullout resistance can be maximised by placing the top screw as close as possible to the top endplate and the bottom screw as close as possible to the bottom endplate, although this will have detrimental effects on the pullout of the second screw should the top screw pull out. Screw angulation is a less important factor but any angulation should be in a cephalad direction and around 10º in magnitude. The experimental results also suggest that the use of a staple may play a role in preventing cephalo-caudad pre-compression forces from reducing screw resistance to subsequent pullout forces.
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Dudko, O. G. "Biomechanical evaluation of mechanical strength of metal and PLA/PGA screws used for internal fixation of long bone fractures." Thesis, БДМУ, 2021. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/18649.
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Mannanal, Subash Kuriakose. "Biomechanical Evaluation of Hybrid Locked Plating for Humeral Shaft Fracture Fixation." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1259180169.
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Rosa, Rodrigo César. "Influência do preparo do orifício piloto e da freqüencia de colocação do implante no seu torque de inserção e resistência ao arrancamento." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/17/17142/tde-07012008-132540/.
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O objetivo do estudo foi avaliar a influência do diâmetro do orifício piloto e a freqüência da colocação dos implantes no torque de inserção e na resistência ao arrancamento. Foram utilizados parafusos de 5, 6 e 7mm do sistema USS de fixação vertebral, os quais foram inseridos nos corpos de prova de madeira, poliuretana, polietileno e osso bovino. Para inserção dos implantes foram confeccionados com broca orifícios piloto com diâmetros menor, igual e maior que o diâmetro interno do parafuso. O torque de inserção dos parafusos avaliado nos corpos de prova de madeira foi mensurado por meio de torquímetro com capacidade de 5Nm, e nos demais corpos de prova foi utilizado torquímetro de 2Nm. Os ensaios mecânicos de arrancamento dos parafusos foram realizados utilizando máquina universal de ensaio Emic? e Software Tesc 3.13 para análise dos resultados, utilizando células de carga com capacidade de 2000 N e 20000 N, selecionadas de acordo com a resistência mecânica de cada corpo de prova, e com velocidade de aplicação de força de 2 mm/min. Os valores do torque de inserção dos parafusos de 5, 6 e 7mm de diâmetro externo, nos diferentes materiais, apresentaram maiores valores de torque na primeira inserção, com exceção dos corpos de prova de poliuretana com orifício piloto de 5,5mm. O diâmetro do orifício piloto em relação ao diâmetro interno do parafuso apresentou influência no torque de inserção dos implantes, nos diferentes corpos de prova, observando maior torque de inserção nos corpos de prova com orifício piloto menor que o diâmetro interno do parafuso e menor torque de inserção nos corpos de prova com diâmetro do orifício piloto maior que o diâmetro interno do parafuso. A força máxima de arrancamento nos parafusos de 5, 6 e 7mm de diâmetro externo, inseridos nos diferentes corpos de prova, apresentaram maiores valores na primeira inserção nos diferentes diâmetros de orifício piloto. O diâmetro do orifício piloto em relação ao diâmetro interno do parafuso apresentou influência na força máxima de arrancamento dos implantes, nos diferentes corpos de prova, observando maior força de arrancamento nos corpos de prova com orifício piloto menor que o diâmetro interno do parafuso e menor força de arrancamento nos corpos de prova com diâmetro do orifício piloto maior que o diâmetro interno do parafuso. Podemos concluir que a freqüência de colocação dos implantes influencia na qualidade da ancoragem. A realização de menor freqüência de colocação dos implantes proporciona uma melhor fixação. A perfuração do orifício piloto com instrumental de menor diâmetro, em relação ao diâmetro interno do parafuso, tende a apresentar melhor fixação do parafuso que a perfuração com diâmetro maior.<br>The aim of the study was to evaluate the influence of the diameter of the pilot hole and the frequency of screw placement on pullout out resistance and insertion torque of the pedicle screw. Pedicle screws of 5, 6 and 7mm of the USS system for vertebral fixation were inserted into wood, polyurethane, polyethylene and bovine bone. The pilot hole for screw insertion was drilled with small, equal and wider than the internal diameter of the screw. The insertion torque was measured in the wood test bodies used a torquímetro with capacity of 5Nm, and other test bodies was used a torquimetro of 2Nm. Mechanical pullout assays were performed using a universal testing machine rehearsals of screws pullout were accomplished using universal machine Emic® and Software Tesc 3.13 for analysis of the results. Load cells were using with capacity of 2000 N and 20000 N, selected in agreement with the mechanical resistance of each test bodies. A constant displacement rate of 2mm/min was applied until failure. The values of the insertion torque of the screws of 5, 6 and 7mm of external diameter, in the different materials, they presented highest insertion torque in the first insert, in the different materials, except for the polyurethane test bodies with pilot hole of 5,5mm. The diameter of the pilot hole in relation to the internal diameter of the screw exerts an influence in the torque of insert of the implants. We observed highest insert torque in the test bodies with smaller pilot hole than the internal diameter of the screw and smaller insert torque in the proof bodies with diameter of the wider pilot hole than the internal diameter of the screw. The pullout resistance of the screws of 5, 6 and 7mm of external diameter performed highest values in the first screw insert, in the different diameters of pilot hole and test bodies. The diameter of the pilot hole in relation to the internal diameter of the screw exerts an influence in the pullout resistance of the implants. The highest pullout resistance was observed in the test bodies with smaller pilot hole than the internal diameter of the screw. The smaller pullout resistance was observed in the test bodies with diameter of the larger pilot hole than the internal diameter of the screw. We can conclude that the frequency of placement of the implants influences in the quality of the anchorage. The accomplishment of smaller frequency of placement of the implants provides a better fixation. The perforation of the pilot hole with instrumental of smaller diameter, in relation to the internal diameter of the screw, tends to present better fixation of the screw than the perforation with larger diameter.
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Garcia, Bonilla Alvaro Antonio. "Ex-vivo Equine Medial Tibial Plateau Contact Pressure with an Intact Medial Femoral Condyle, with a Medial Femoral Condylar Defect, and After Placement of a Transcondylar Screw through the Condylar Defect." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397472874.
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Malan, Freddie. "An in vitro biomechanical comparison between intramedullary pinning and the use of plates in the dachshund tibia." Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/24914.
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The dachshund, a chondrodystrophic dog breed, presents a unique challenge in the treatment of tibial fractures by having short and curvaceous tibiae, leading to high implant failure risk. In this study, intramedullary pins with full cerclage wires as an option in the treatment of oblique diaphyseal tibial fractures was studied in vitro. This fixation technique was biomechanically compared with the current gold standard in internal stabilization, namely bone plates and screws. Twenty tibiae recovered from adult dachshund cadavers were randomly allocated into two groups of ten bones each. Oblique fractures running in a proximo-cranial-disto-caudal direction in the middle third of the tibial diaphysis were simulated by osteotomy and each bone repaired by using one of the following methods: <ul> <li> Pre-bent intramedullary pin, filling 40% to 60% of the medullary cavity at its narrowest point, inserted normograde and combined with a set of three full cerclage wires (group 1).</li> <li> Lag screw at the osteotomy site, combined with a six hole 2.7 mm contoured dynamic compression plate and cortical screws in neutral mode (group 2).</li> </ul> Each test specimen was subjected to a two point single cycle axial compression test by applying a standardized, increasing compression load to the point of fixation failure or bone collapse. A stress-strain graph for each test specimen was drawn from the raw data. Radiographs and digital photographs were made pre-osteotomy, post-osteotomy, post-repair and post-test, and modes of failure noted for each test specimen. Stress (applied load) and strain (deformation) at yield, ultimate strength, and at failure were determined for each test specimen from the stress-strain graphs and the mean values statistically compared between the groups using the ANCOVA method. Significance levels of p < 0.05 were used, while p < 0.1 and p < 0.01 were also indicated. In group 1, 50% specimens failed due to unraveling or slippage with displacement of the cerclage wires, 30% due to bone fracture at a cerclage wire, and 20% due to bone fracture elsewhere. In group 2, 80% specimens failed due to bone fracture at one or more of the screw holes, whereas 20% failed due to bone fracture not directly associated with implants. No bone plate or screw underwent plastic (permanent) deformation, whereas 80% of the intramedullary pins and 30% of the cerclage wires underwent plastic deformation. Mean stress at the yield point in groups 1 and 2 were 0.323 MPa and 0.403 MPa respectively, at the point of ultimate strength 0.383 MPa and 0.431 MPa respectively, and at the failure point 0.345 MPa and 0.403 MPa respectively. Mean strain at the yield point in groups 1 and 2 were 0.296% and 0.362% respectively, at the point of ultimate strength 0.412% and 0.472% respectively, and at the failure point 0.713% and 0.838% respectively. Clinically, there was an indication that plates and screws were more resistant to deformation by the loads applied than intramedullary pins and cerclage wires. However, statistically, there were no significant differences in stress at yield (p = 0.299), ultimate strength (p = 0.275), or failure (p = 0.137) between the two groups. Similarly, there were no significant differences in strain at yield (p = 0.684), ultimate strength (p = 0.778), or failure (p = 0.505) between the two groups. Main limitations of the study were the relatively small number of specimens tested, the smoothness of the osteotomy cuts which limited interdigitation between the fragments, and that only three of the five recognized loads acting on bones in vivo, were tested in vitro. In conclusion, this study did not show enough evidence to prove a significant difference between the two methods of fixation. Therefore, it is suggested that intramedullary pins and full cerclage wires be used as an acceptable alternative to bone plates and screws in the treatment of oblique mid-diaphyseal tibial fractures in chondrodystrophic dog breeds.<br>Die dachshund, ‘n chondrodistrofiese honderas, bied ‘n unieke uitdaging in die behandeling van frakture van die tibia, deurdat hulle tibias kort en krom is, wat lei tot ‘n hoë risiko van inplantaat mislukking. In hierdie studie is intramedullêre penne met vol sirkeldrade as ‘n keuse in die behandeling van skuins frakture van die tibiale skag in vitro bestudeer. Hierdie tegniek van herstel is vergelyk met die huidige goue standaard in interne stabilisering, naamlik beenplate en skroewe. Twintig tibias wat van volwasse dachshund kadawers herwin is, is lukraak aan twee groepe van tien bene elk toegewys. Skuins frakture in ‘n proksimo-kranio-disto-koudale rigting in die middelste derde van die tibiale skag is nageboots deur ‘n osteotomie, waarna elke been herstel is deur die gebruik van een van die volgende metodes: <ul> <li> Vooraf gebuigde intramedullêre pen, wat 40% tot 60% van die murgholte by die dunste punt vul, normograad geplaas en gekombineer met ‘n stel van drie vol sirkeldrade (groep 1).</li> <li> Trekskroef by die osteotomie area, gekombineer met ‘n ses-gat 2.7 mm gekontoerde dinamiese drukplaat en kortikale skroewe geplaas op neutrale wyse (groep 2).</li> </ul> Elke toetsmonster is onderwerp aan ‘n twee-punt enkel siklus aksiale druktoets deur die toepassing van ‘n gestandardiseerde, verhogende druklading tot by die punt van fiksasie breuk of kollaps van die been. ‘n Druk-spanning grafiek vir elke toetsmonster is vanaf die rou data saamgestel. X-straalfoto’s en digitale foto’s van elke been is pre-osteotomie, post-osteotomie, post-herstel and post-toets geneem en die maniere van faal vir elke toetsmonster aangeteken. Druk (toegepaste lading) en spanning (vervorming) by meegee (“yield”), treksterkte (“ultimate strength”) en faal (“failure”) is vir elke toetsmonster bepaal vanaf die druk-spanning grafieke en die gemiddelde waardes statisties vergelyk tussen die groepe deur gebruik te maak van die ANCOVA metode. Beduidenis vlakke van p < 0.05 is gebruik, terwyl p < 0.1 en p < 0.01 ook aangedui is. In groep 1 het 50% toetsmonsters gefaal as gevolg van losgaan of gly van die sirkeldrade met verplasing, 30% as gevolg van beenfrakture by ‘n sirkeldraad, en 20% as gevolg van beenfrakture elders. In groep 2 het 80% toetsmonsters gefaal as gevolg van beenfrakture by een of meer skroefgate, terwyl 20% gefaal het as gevolg van beenfrakture wat nie direk met die inplantate geassosieer is nie. Geen beenplaat of skroef het plastiese (permanente) vervorming ondergaan nie, terwyl 80% van die IM penne en 30% van die sirkeldrade plastiese vervorming ondergaan het. Gemiddelde druk by die meegeepunt in groepe 1 en 2 was 0.323 MPa en 0.403 MPa onderskeidelik, by die punt van treksterkte 0.383 MPa en 0.431 MPa onderskeidelik, en by die faalpunt 0.345 MPa en 0.403 MPa onderskeidelik. Gemiddelde spanning by die meegeepunt in groepe 1 en 2 was 0.296% en 0.362% onderskeidelik, by die punt van treksterkte 0.412% en 0.472% onderskeidelik, en by die faalpunt 0.713% en 0.838% onderskeidelik. Klinies was daar ‘n indikasie dat plate en skroewe meer weerstandbiedend was teen vervorming deur die toegepaste ladings as intramedullêre penne en sirkeldrade. Statisties was die druk wat die toetsmonster laat meegee (p = 0.299), en die druk by die treksterkte- (p = 0.275) en faalpunte (p = 0.137) egter nie beduidend verskillend tussen die twee groepe nie. Net so was die spanning by die meegee- (p = 0.684), treksterkte- (p = 0.778) en faalpunte (p = 0.505) nie beduidend verskillend tussen die twee groepe nie. Hoof beperkings van die studie was die relatief klein getal monsters wat getoets is, die gladheid van die osteotomie-snitte wat interdigitasie tussen die fragmente beperk het, en dat slegs drie van die vyf erkende ladings wat op bene in vivo inwerk, in vitro getoets kon word. Laastens het hierdie studie nie genoeg getuienis opgelewer om ‘n beduidende verskil te bewys trussen die twee metodes van herstel nie. Derhalwe word voorgestel dat IM-penne en vol sirkeldrade gebruik word as aanvarbare alternatief tot beenplate en skroewe in die behandeling van skuins midskag tibia frakture in chondrodistrofiese honderasse.<br>Dissertation (MSc)--University of Pretoria, 2012.<br>Companion Animal Clinical Studies<br>unrestricted
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Sasaki, Sandra Umeda. "Estudo comparativo entre dois métodos de tratamento da lesão do ligamento cruzado posterior por avulsão óssea na tíbia : amarrilho artroscópico e fixação com parafuso por via posterior aberta." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/5/5140/tde-19042007-115606/.
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Atualmente, os bons resultados na lesão do ligamento cruzado posterior por avulsão óssea na tíbia associam-se ao tratamento cirúrgico e precoce. A técnica convencional é a fixação com parafuso pela via de acesso posterior do joelho, com abordagem direta das estruturas vasculares e nervosas da região. Neste estudo experimental em 20 joelhos de cadáveres, buscamos apresentar uma alternativa com amarrilho por via artroscópica, comparando-o com a técnica convencional, através da inspeção direta e de testes biomecânicos. Houve falha na fixação de apenas um exemplar de cada método e medidas de deslocamento tibial posterior (p=0,23) e rigidez média (p=0,28) sem diferenças significativas entre as duas técnicas. Concluímos ser o amarrilho artroscópico viável e uma alternativa no tratamento desta lesão.<br>Nowadays, good results on the management of posterior cruciate ligament bony avulsion of the tibia are associated with early surgical repair. The usual method of treatment is the open posterior approach with screw fixation, wich requires popliteal neurovascular bundle direct manipulation. This study presents a new arthroscopic suture and compares it with the conventional technique, using biomechanical tests and direct inspection in cadaveric specimens (20 knees). On both methods there was a fixation fail in one knee. The analisys of tibial posterior displacement (p=0,23) and stiffness (p=0,20) were similar for the two methods. The Arthroscopic suture presented is an effective reattachment method for this fracture pattern.
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Patel, Vinit A. "Biomechanical Evaluation Of Locked and Non-locked Constructs Under Axial And Torsion Loading." Wright State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=wright1228776190.
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Raikar, Sajal Vijay. "Cement Augmentation Enhanced Pullout Strength Of Fatigue Loaded Bone Screws." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1226240822.
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Gilbert, Stephen Gregory. "Bending fatigue of cancellous bone screws used in anterior spine surgery." Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/6491.
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Bending fatigue has been noted in early clinical results of anterior spinal fixation using standard 6.5mm outside diameter (3.2mm inside diameter) cancellous bone screws. Fractography was used to qualify and quantify the failure mode. Fracture mechanics was used to determine the load level from the fractographic findings. These results were used in a test program to reproduce the fatigue failures seen in-vivo. The validity of the experimental model was investigated by varying test coupon parameters, testing the modified specimens and comparing the results to those predicted.
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Rozema, Frederik Reinder. "Resorbable poly(L-lactide) bone plates and screws tests and applications /." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 1991. http://irs.ub.rug.nl/ppn/29129460X.
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Newman, Kyle D. "3D Modeling and Finite Element Analysis of Femur After Removing Surgical Screws." OpenSIUC, 2016. https://opensiuc.lib.siu.edu/theses/2025.
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Often bone fractures are joined by inserting metal plates and screws to hold the fragmented bone under compression. However, after the fractured bone is healed removing the screws leaves holes in the bone which takes months to fill up and heal completely. The goal of this research is to investigate those voids specifically in a finite element model of a femur. The holes were found to experience high stress that can easily lead to crack propagations during everyday activities. Finite element models of femurs were modeled after two common fracture fixation systems, specifically just after the plates, rods and screws are removed. To observe the stress levels bones are likely to experience, common mechanical tests that are relevant to or associated with common daily activities were performed. While the 3-point bending tests did not yield significant results, the compression and torsion tests produced high stress areas near the screw holes. In certain cases, the von Mises’ stress reached 3.66 x 106 N/mm2. Our finite element modeling seeks to establish groundwork for future explorations on the holes created by fracture fixation hardware. In the future, this work will lead to redesigning of fixation systems with reduced stress concentration around the holes. Therefore, the initiation of new cracks around these holes will be limited during everyday activity.
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Tams, Jan. "Suitability of polylactide bone plates and screws for fixation of mandibular fractures." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 1998. http://irs.ub.rug.nl/ppn/292801297.
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Estes, Bradley T. "A biomechanical analysis of the plates and screws implanted in posterior cervical spine plating via the lateral mass." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/19481.
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Battula, Suneel Ranga Sai. "Experimental and Numerical Evaluation of the Pullout Strength of Self-tapping Bone Screws in Normal and Osteoporotic Bone." University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1194988102.
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Choi, Yi-king. "Computer visualization techniques in surgical planning for pedicle screw insertion /." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk:8888/cgi-bin/hkuto%5Ftoc%5Fpdf?B22956475.
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Cavalieri-Pereira, Lucas 1982. "Resistência de três tipos de fixação utilizados no tratamento das fraturas do ângulo mandibular." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/287857.
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Orientadores: Alexandre Elias Trivellato, Marcio de Moraes<br>Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-08-21T07:03:24Z (GMT). No. of bitstreams: 1
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Previous issue date: 2012<br>Resumo: Fraturas do ângulo mandibular são muito freqüentes dentre as fraturas mandibulares e um das formas de tratamento é a utilização de fixação interna com placas e parafusos. Neste estudo o objetivo foi avaliar comparativamente a resistência de três tipos de fixação em réplicas de mandíbula de poliuretano, empregando-se a técnica de Champy. Foram utilizadas 63 mandíbulas dentadas, submetidas aa seccionamento simulando uma fratura linear e favorável de ângulo mandibular esquerdo. As fixações foram realizadas com placas retas do sistema 2,0 mm, dispostas da seguinte forma: uma placa com quatro furos, uma com cinco furos e uma com quatro furos e extensão (ponte). A estabilização e fixação foram realizadas com adaptação da placa e quatro parafusos de 6,0 mm de comprimento, sobre a linha oblíqua da mandíbula. Foram elaborados 9 grupos, com 7 mandíbulas cada um, sendo 3 grupos fixados com placa de 5 furos, 3 com placa reta de 4 furos com extensão e 3 com placa reta de 4 furos. Cada conjunto foi submetido ao teste de carregamento linear com aplicação de carga no sentido súpero-inferior em três pontos distintos da mandíbula, de modo não simultâneo (região de molar ipsilateral à secção, incisivos centrais e molar contralateral) em máquina de ensaio universal EMIC DL 2000. Foram mensurados valores de carga no deslocamento de 1 mm, 2 mm e final e anotado o deslocamento final. Os resultados obtidos foram submetidos à análise estatística, utilizando a análise de variância (ANOVA), seguido do teste de Tukey, nível de significância de 5%. Nos valores de cargas obtidos, tanto quando aplicada no molar ipsilateral ao seccionamento, no molar contralateral ao seccionamento e entre incisivos centrais, foi verificada diferença estatística somente no momento do deslocamento final, na qual a placa com 5 furos e com 4 com extensão foi superior a placa com quatro furos. Não houve diferença entre placa com 5 furos e com 4 com extensão<br>Abstract: Mandibular angle fractures are very frequent among the mandibular fractures and a form of treatment is the use of internal fixation with plates and screws. In this study, the objective was to evaluate the resistance of three types of fixation in mandibular replicas of polyurethane, using the technique of Champy. Sixty three toothed mandibles were used, subject to sectioning simulating a linear and favorable fracture of left mandibular angle. The fixations were performed with straight plates system 2.0 mm, prepared as follows: one plate with 4-holes, one with 5-holes and one 4-holes and extension (bridge). Stabilization and adjustment were performed with locking plate and four screws of 6.0 mm in length, about the oblique line of the mandible. Nine groups were elaborated, with 7 each, which 3 groups being fixed with 5-holes plates, 3 groups with 4-holes plates with extension and 3 groups with 4-holes plates. Each set was submitted for loading test with load application towards in three distinct points of the mandible, so do not simultaneously (molar region on the side ipsilateral of section, the central incisors and contralateral molar) in universal testing machine EMIC DL 2000. Load values were measured at offset 1 mm, 2 mm and final and was noted the final dislocation. The results were submitted to statistical analysis, using analysis of variance (ANOVA) followed by Tukey test, a significance level of 5%. The values obtained, when loads were applied in the ipsilateral molar, contralateral molar and incisors, was verified statistically only at the final dislocation, in which the 5-holes plates and 4-holes with extension was more resistant than 4-holes plates. There was no difference between plate with 5-holes and 4-holes with extension<br>Doutorado<br>Cirurgia e Traumatologia Buco-Maxilo-Faciais<br>Doutor em Clínica Odontológica
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Bagnall, Anne-Marie. "Effects of osteoporosis and drugs on bone biomechanics." Thesis, Queen Mary, University of London, 1996. http://qmro.qmul.ac.uk/xmlui/handle/123456789/1512.
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16 New Zealand White (NZW) rabbits were ovariectomised (OVX) and 20 left intact as age-matched controls. 4 controls were killed at time 0, then 4 from each group at 1,3,6 and 12 months post-OVX. Serum oestradiol and body weight were recorded. Post-mortem of the OVX animals confirmed that all ovarian tissue had been removed. Femoral and humeral diaphyses were tested in 4-point bending, metatarsals in torsion and cancellous bone from the femora and humeri in compression. Oestradiol levels were not altered by OVX and there were no significant reductions in strength, stiffness or density of cancellous or cortical bone 12 months post-OVX, except that OVX femoral strength was significantly lower than control strength (p < 0.05). In conclusion, the species was not a suitable model for post-menopausal osteoporosis. Due to the failure of the rabbit model, it was necessary to revert to the rat model of post-menopausal osteoporosis. Two mechanical tests were used to investigate the efficacy of an anti-resorptive therapy (Oestradiol-3-benzoate) and an anabolic therapy (Parathyroid Hormone). An indentation test examined the properties of cancellous bone material, while the femoral neck bending test examined the properties of the bone as an organ by reproducing the in vivo events leading to a shear fracture of the hip. Biomechanical variables were related to Bone Mineral Density, a measure of bone mass currently in use in clinical practice, by scanning the bones using peripheral quantitative computed tomography (pQCT) before mechanical testing took place. It was found that cancellous bone density and indentation strength decreased and cortical bone density increased 6 weeks post-OVX: high levels of oestradiol-3- benzoate prevented these changes . Total bone mineral density was strongly correlated with indentation strength (r=0.92). Parathyroid hormone did not restore cancellous bone density of OVX to sham levels but restored biomechanical strength.
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Newcombe, Lindsay Kathleen. "Biomechanics of limb prostheses directly attached to bone." Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/1443994/.
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The technique of attaching a limb directly to the skeleton has clear benefits, when compared with socket-attachment, for the many amputees who encounter skin problems. A potential risk of attaching a limb to the skeleton is the wound where the implant breaches the skin. At the Centre for Biomedical Engineering in the Institute of Orthopaedics and Musculoskeletal Science at UCL, a method has been devised which enhances epithelial attachment to the implant, resisting infection, and this has been used to develop a system for attaching a limb to the skeleton: Intraosseous Transcutaneous Amputation Prosthesis, or ITAP. In a transfemoral prosthesis, protection of bone from external loading is anticipated and in this thesis a fail-safe component is designed to prevent fracture. It has adjustable activation levels and has been tested to the appropriate International Standards. In order to determine loads that are to be allowed and prevented, normal loading of the femur during ordinary activities is researched failure modes of femoral bone are investigated. Finite element analysis is employed to investigate the stress distribution throughout the femur with the attachment of a prosthetic leg. A cylindrical model is used to assess the effect of varying geometry and material properties of the bone and implant. An anatomical model, derived from a CT scan, is used to analyse the effect of stump length. There are three risk groups that the amputee can be allocated depending on the level of amputation, the size of the bone, and the amount of bone contact with the implant. At the beginning of rehabilitation the fail-safe is set low to protect the poorer bone and bone-implant interface. The settings are gradually increased during rehabilitation to 60Nm, 80Nm or 100Nm in bending and 10Nm, 15Nm and 25Nm in torsion for high, medium and low risk amputees respectively.
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Tuchman, Marni. "COMPARISON OF INSERTION ANGULATIONS MEASURED VIA BONE-TO-IMPLANT CONTACT OF MINI-SCREWS USING MICRO-CT." Master's thesis, Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/520294.
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Oral Biology<br>M.S.<br>Bone-to-implant contact of orthodontic mini-screws has been determined via Micro-CT to be a strong predictor of primary stability. Various insertion angulations, including both 900 and 500, have been reported as ideal for providing optimum primary stability. The aim of this investigation was to determine if a statistically significant difference exists in the bone-to-implant contact of mini-screws placed with an insertion angulation of 900 compared to those placed at 500 as determined via Micro-CT. Ten self-drilling, self-tapping orthodontic mini-screws (Aarhus,1.5mmx6mm) (n=5) were inserted into the posterior ramus of an adult pig mandible, an analog to an adult human mandible. A custom stent with ten holes, five at 900 and five at 500, was fitted to the bone surface to control insertion angulation. The bone was cut to 1.5x1.5x1cm segments and scanned using SkyScan 1127 with ideal specifications (8mm pixel size, medium camera, 80Kv, 100mA, 10W, 1800 rotation, and 0.5Al+0.25Cu filter). The raw scans were reconstructed using NReconV1.6.10 and these datasets were then reoriented using DataviewerV1.5.2 along the Z-axis to standardize the peri-implant bone for analysis. A custom task-list was used with CT-AnalyzerV1.14.41 to determine the percent of bone-to-implant contact per mini-screw. A Mann-Whitney U test indicated that the bone-to-implant contact was not statistically significantly different for the mini-screws placed at 900 (Mdn= 72.34) compared to the mini-screws placed at 500 (Mdn= 53.25), U=5, p=.1443. Therefore, the results do not significantly differ at p<.05. There is no statistically significant difference in the bone-to-implant contact between the Aarhus 1.5mmx6mm orthodontic mini-screws placed at 900 compared to those placed at 500 as measured by Micro-CT. This may lead to the conclusion that there is no significant difference in the primary stability of Aarhus mini-screws placed at 900 and 500.<br>Temple University--Theses
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Epshteyn, Leonid. "OPTIMAL SPECIFICATIONS FOR MEASURING BONE-TO-IMPLANT CONTACT OF MINI-SCREWS USING MICRO-CT." Master's thesis, Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/395373.
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Oral Biology<br>M.S.<br>The use of mini-screws (MSs) as temporary anchorage devices (TADs) is becoming more common in orthodontic treatment. With the increased use of TADs and the numerous manufactures producing them, research is needed to aid orthodontists in their selection of MSs. One of the major advantages of using mini-screw implants is that they can be loaded immediately and do not require osseoitegration.1 For this to be successful, the mini-screw needs to have adequate primary stability to retain itself in the bone. The mini-screw bone system relies on the stability of the mini-screw, the stability of the bone, and the stability of their interface.19,20 In the literature, this stability if usually quantified by measuring the pullout force, insertion torque and bone-to-implant contact.25,26 To date, much of the research has demonstrated that the geometric configuration of the mini-screw plays a significant role in its primary stability. Features such as pitch (length between threads), thread body design, screw length and diameter factor into primary stability.5,21,23 In order to observe the bone-to-implant contact traditionally, researchers had to perform histologic section. This method is destructive to the sample and does not allow it to be used for other analyses such as pullout force. With micro-CT technology, it is now possible to study the bone-to-implant relationship without destroying the sample and with great accuracy.6 Currently, it is unclear as to the optimal scanning specification to choose when using a micro-CT to measure bone-to-implant contact. The optimal scan is one, which provides the most accurate measurement within the least amount of time. The highest quality scans increase both time and costs of acquisition, while lower quality scans have the potential of introducing inaccuracies. This study aims to determine the optimal specifications needed to scan a mini-screw in bone using a SkyScan 1172 micro-CT, to measure the bone-to-implant contact. A total of three orthodontic mini-screws from Aarhus (American Orthodontics, Sheboygan, Wisc), 1.4 mm in diameter and 8 mm long were inserted into an adult pig mandible. All three mini-screws were inserted into the lingual area in the molar region. Each mini-screw was inserted until all the threads were buried into the bone. After placement, the blocks of bone containing the individual mini-screw were cut out and shaped to facilitate scanning by micro-CT. Each sample was be positioned and scanned individually using micro-CT (SkyScan 1172; SkyScan, Aartselaar, Belgium) under 5 different specifications, see table 1. SkyScan software was used to process the scans and calculate qualitative and quantitative data. For each sample bone-to-implant contact was measured. The software measured the TS, which is the area of the mini-screws surface and the IS, which is where the bone interfaces with the mini-screws. The IS/TSx100 was determined to be the percentage of the mini-screws surface that is in contact with bone or the bone-to-implant contact. Qualitative and quantitative analyses were performed to determine statically significant differences between the various bone-to-implant contact measurements of the samples. BIC varied greatly between the scanning specifications and samples, from 0% to 70.35%. Quantitative and qualitative analysis was performed to compare the differences in BIC(%) values between the 5 specifications. Two of the three samples displayed an accuracy of greater than 95% for specification 3, thus providing latitude in adjustment/reduction of scanning times with minimal variance in data accuracy for BIC(%). The results show for measuring BIC(%), scanning specifications can be modified/optimized to reduce scanning time while maintaining acceptable accuracy when scanning of large sample sizes are needed. It is recommended that for studies where absolute BIC(%) is needed, specification 5 is recommended since it will provide the most accurate measurement. For studies that are comparing changes in BIC(%), specification 3 is recommended as it will provide an acceptable level of accuracy in a reasonable amount time. However, due to limited sample size, more data is needed.<br>Temple University--Theses
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Chow, Lop-keung Raymond. "Clinical morbidity of resorbable plates and screws for internal fixation in orthognathic surgery." Click to view the E-thesis via HKUTO, 2003. http://sunzi.lib.hku.hk/hkuto/record/B31954285.
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Chow, Lop-keung Raymond, and 周立強. "Clinical morbidity of resorbable plates and screws for internal fixation in orthognathic surgery." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31954285.
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Brasileiro, Bernardo Ferreira. "Avaliação biomecanica in vitro de tecnicas de fixação rigida metalica para osteotomia sagital do ramo mandibular em movimentos de avanço e recuo." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289676.
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Orientador: Luis Augusto Passeri<br>Tese doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-08-09T20:14:50Z (GMT). No. of bitstreams: 1
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Previous issue date: 2007<br>Resumo: Um melhor entendimento biomecânico da fixação interna rígida (FIR) na osteotomia sagital dos ramos mandibulares (OSRM) pode ser baseado em pesquisas com o intuito de investigar sua função in vitro antes da aplicação clínica. Assim, este trabalho teve como objetivo avaliar comparativamente a resistência de três diferentes técnicas de FIR em réplicas de hemimandíbulas humanas de poliuretano simulando a OSRM para movimentos de 5 mm em avanço e recuo. As técnicas de FIR incluíram uma miniplaca ponte com 4 furos e 4 parafusos monocorticais (grupo miniplaca), uma miniplaca com 4 furos e 4 parafusos monocorticais mais um parafuso bicortical posicional (grupo híbrido) e 3 parafusos bicortical posicionais em configuração em ¿L¿ invertido (grupo ¿L¿ invertido). Os parafusos e as miniplacas utilizados eram de titânio e pertencentes ao sistema de 2,0 mm. Estes foram avaliados quanto à padronização dimensional por meio do coeficiente de variação, que evidenciou alta semelhança macroscópica. As hemimandíbulas foram submetidas a testes de carregamento linear vertical e lateral por uma unidade de testes mecânicos Instron 4411 para registro da carga de pico aos deslocamentos de 1 mm, 3 mm, 5 mm e 10 mm. Médias e desvio padrão foram avaliados aplicando-se a Análise de Variância e o teste de Tukey em nível de significância de 5%. O grupo miniplaca apresentou menores valores de carga de pico ao deslocamento (p<0,01) quando comparada com as outras técnicas de fixação considerando-se igual tipo de movimento e direção de carga. O grupo ¿L¿ invertido foi ainda superior em resistência (p<0,01) ao grupo híbrido em movimento de avanço e com aplicação de carga verticalmente. Concluiu-se que a utilização da técnica de FIR para a OSRM baseada em 3 parafusos bicorticais em ¿L¿ invertido foi a mais estável, e que a colocação de um parafuso bicortical pode otimizar significativamente a resistência da fixação com miniplacas e parafusos monocorticais<br>Abstract: A better understanding of the biomechanics of sagittal split ramus osteotomy (SSRO) rigid internal fixation (RIF) can be based on research aiming to evaluate its function in vitro before clinical application. Thus, the goal of this investigation was to evaluate comparatively the resistance of three different RIF techniques applied to polyurethane synthetic hemi-mandible replicas simulating the SSRO for 5 mm advancement and setback. RIF techniques included a 4-hole miniplate and 4 monocortical screws (miniplate group), a 4-hole plate and 4 monocortical screws with one additional bicortical positional screw (hybrid group), and 3 bicortical positional screws in a traditional inverted-L pattern (inverted-L group). Screws and miniplates were made of titanium and from 2.0 mm system. These were analyzed according to dimensional standardization by a coefficient of
variation, which revealed high macroscopic similarity. The hemi-mandibles were submitted lateral and vertical loading tests in an Instron 4411 mechanical testing unit for recording of peak loading at 1 mm, 3 mm, 5 mm and 10 mm of displacement. Means and standard deviation were analyzed using Analysis of Variance and Tukey test with a 5% level of significance. Miniplate group showed lower load peak scores (p<.01) when compared to the others fixation techniques regarding equal type of movement and force direction. Inverted-L group demonstrated higher resistance (p<.01) than hybrid group during advancement and with application of vertical load. It was concluded the RIF technique for SSRO based on 3 bicortical screws in the inverted-L pattern was the most stable, and the installation of a bicortical screw may significantly optimize the resistance of the miniplate and monocortical screws fixation<br>Doutorado<br>Cirurgia e Traumatologia Buco-Maxilo-Faciais<br>Doutor em Clínica Odontológica
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Iamashita, Heric Yukio. "Estudo biomecanico de tres tecnicas diferentes de fixações metalicas utilizadas em osteotomia sagital do ramo mandibular." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/290201.
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Orientadores: Valfrido Antonio Pereira Filho, Luis Augusto Passeri<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-08-13T11:01:55Z (GMT). No. of bitstreams: 1
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Previous issue date: 2009<br>Resumo: Estudos têm proposto diversas técnicas e métodos de fixação interna rígida (FIR) no sentido de se obter maior estabilidade dos segmentos ósseos e mínimo deslocamento condilar após osteotomia sagital do ramo mandibular (OSRM). Desta forma, o presente estudo teve por objetivo avaliar por meio de ensaio mecânico de compressão em hemimandíbulas sintéticas, três diferentes tipos de fixações utilizadas na OSRM em movimento de avanço de 5 mm. Foram utilizadas 30 hemimandíbulas, divididas em 3 grupos com 10 hemimandíbulas em cada. O grupo 1 foi fixado com três parafusos posicionais de 15 mm do sistema 2,0 mm dispostos bicorticalmente na posição de L invertido e com angulação de inserção de 90°; no Grupo 2 a fixação foi realizada com placa de 4 furos do sistema 2,0 mm e 4 parafusos monocorticais de 6 mm de comprimento disposto sobre a região do canal mandibular, e o Grupo 3 a fixação consistiu de uma placa sagital ajustável do sistema 2,0 mm e 8 parafusos de 6,0 mm de comprimento também localizada sobre o canal mandibular. Sendo avaliados quanto à padronização, o sistema de fixação demonstrou semelhança dimensional. As hemimandíbulas foram submetidas a cargas compressivas verticais, por meio de ponta de aplicação de carga em máquina de ensaio universal MTS®, na velocidade de 1 mm/min com deslocamento máximo de 10 mm. Médias e desvios padrão foram obtidos e submetidos à análise de variância a um fator e teste HSD de Tukey com nível de significância de 5%. O Grupo 1 apresentou maiores valores
de resistência à força de carga compressiva (p<0,001) sendo superior aos demais grupos. O Grupo 3 demonstrou a menor resistência às forças (p<0,001). Concluiuse que o uso de parafusos bicorticais posicionais em L invertido promove a maior capacidade de resistência às cargas compressivas, sendo que as placas sagitais ajustáveis apresentam-se cerca de 60% menos resistentes do que o Grupo 1.<br>Abstract: Studies have considered many techniques and methods of rigid internal fixation (RIF) leads to obtain greater stability to the bone segments and minimum displacement of the condyles after performed the sagittal split ramus osteotomy (SSRO). In this way, the purpose of this study was to evaluate by means of mechanical compression testing model with synthetic hemimandibles, three different fixation types used in the SSRO in movement of advance of 5 mm. Thirty hemimandibles, divided in 3 groups with 10 hemimandibles in each group. Group 1 was fixed with three 15 mm positional screws (2.0 mm diameter) bicortically in an inverted-L pattern and with insertion angle of 90°; in Group 2 the fixation was carried through with four-hole straight plate and four 6 mm monocortical screws made located on the region of the mandibular canal, and Group 3 the fixation is consisted of an adjustable sagittal plate and eight 6 mm screws also placed on the mandibular canal. Evaluated for dimensional standardization, the fixation system had demonstrated dimensional similarity. Hemimandibles had been exposed to the vertical compressive loads, by means of tip of load application in a MTS® mechanical testing unit, in the speed of 1 mm/min with maximum displacement of 10 mm. Averages and standard deviations had been obtained and submitted to the analysis of variance to a factor and have tested for HSD of Tukey test with a 5% level of significance. Group 1 presented greaters values of resistance to the compressive loads (p< 0.001) showed superior to the other groups. Group 3 demonstrated the lesser resistance to the loading forces (p< 0.001). It was concluded that the use of positional bicortical screws in inverted-L pattern promotes the higher capacities of resistance to compressive loads, moreover, the adjustable sagittal plates are presented about less resistant 60% that the Group 1.<br>Mestrado<br>Cirurgia e Traumatologia Buco-Maxilo-Faciais<br>Mestre em Clínica Odontológica
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Choi, Yi-king, and 蔡綺瓊. "Computer visualization techniques in surgical planning for pedicle screw insertion." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31224234.
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Warnock, Sarah M. "Cortical Bone Mechanics Technology (CBMT) and Dual X-Ray Absorptiometry (DXA) Sensitivity to Bone Collagen Degradation in Human Ulna Bone." Ohio University Honors Tutorial College / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1556305540256918.
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Hillard, Peter John. "Aspects of the biomechanics of Ilizarov external fixation." Thesis, University of Bristol, 1999. http://hdl.handle.net/1983/9934ff7c-a0fc-4eb4-a2ab-323c07024660.
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The original Ilizarov frame is a form of circular external fixation in which bone fragments are supported by tensioned fine wires; the wires give the frame a nonlinear axial stiffness which is one of its key qualities. However, as the wires deform plastically in response to loads imposed by functional weight bearing, the stiffness of frame gradually decreases with time. To circumvent this problem the modified Ilizarov frame was conceived in which half pins rather than wires are used for bone support. As fractures managed with Ilizarov fixation tend to unite with little radiographic evidence, monitoring the progression of fracture healing is difficult. The study described in this dissertation had three primary objectives. The first was to investigate the significance of the plastic deformation which occurs in the tensioned fine wires to the long term performance of the original frame. The second was to investigate the biomechanics of the modified frame. The third objective was to conduct a in-vivo feasibility study on the use of fracture axial stiffness measurements as method of monitoring the progression of fracture healing. Plastic deformation of the wires in the original frame readily occurs at moderate load levels because stress concentrations arise at the wire-clamp and wire-bone interfaces. The reduction in frame stiffness is typically 20-30%; re-tensioning only temporarily restores the original frame stiffness. In contrast to the original frame, the modified frame displays a linear stiffness and, as the half pins act as cantilevers, shearing of the bone ends can occur under axial loading. The in-vivo study showed that the technique of relative stiffness measurement, which has been successfully applied to uniaxial fixators, is not directly applicable to Ilizarov fixation. However, it was noted that the standardd eviation of repeatm easurementsd ecreasedw ith the progressiono f healing. It is suggestedt hat this may arise as a result of decreasedm icromovement at the fracture site and might provide a means of monitoring fracture healing itself
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Felfel, Reda. "Manufacture and characterisation of bioresorbable fibre reinforced composite rods and screws for bone fracture fixation applications." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/14379/.
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Bioresorbable implants are an attractive alternative to metallic bone fixation devices and offer potential to eliminate some of the clinical challenges with the latter. This work explores the manufacturing of fully bioresorbable fibre-reinforced composite rods and screws for such applications. Poly lactic acid (PLA) and phosphate glass fibres (PGF) were combined to provide mechanical reinforcement and biocompatibility characteristics. Aligned and randomly reinforced PLA/PGF composites were prepared by compression moulding prior to thermomechanical deformation into rod and screw forms. In vitro degradation and mechanical properties retention were investigated in phosphate buffered saline (PBS) at 37°C. The composite rods and screws exceeded published data for bioresorbable implants in their virgin state and were towards the upper range of cortical bone properties. The properties reduced rapidly in an aqueous medium and this was attributed to matrix plasticisation and fibre/matrix disbonding. The degraded samples maintained strength and stiffness close to the lower limits of the cortical bone. Water uptake and mass loss for composites exceeded equivalent values for PLA alone due to water wicking at the fibre/matrix interface. Ion release tests correlated linearly with mass loss profiles confirming that the dominant degradation mechanism was fibre dissolution. The PLA/PGF composites also exhibited good biocompatibility to human osteosarcoma and human mesenchymal stem cells.
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Kemper, Andrew Robb. "The Biomechanics of Thoracic Skeletal Response." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/37635.
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The National Highway Traffic Safety Administration (NHTSA) reported that in 2008 there were a total of 37,261 automotive related fatalities, 26,689 of which were vehicle occupants. It has been reported that in automotive collisions chest injuries rank second only to head injuries in overall number of fatalities and serious injuries. In frontal collisions, chest injuries constitute 37.6% of all AIS 3+ injuries, 46.3% of all AIS 4+ injuries, and 43.3% of all AIS 5+ injuries. In side impact collisions, it has been reported that thoracic injuries are the most common type of serious injury (AISâ ¥3) to vehicle occupants in both near side and far side crashes which do not involve a rollover. In addition, rib fractures are the most frequent type of thoracic injury observed in both frontal and side impact automotive collisions.
Anthropomorphic test devices (ATDs), i.e. crash test dummies, and finite element models (FEMs) have proved to be integral tools in the assessment and mitigation of thoracic injury risk. However, the validation of both of these tools is contingent on the availability of relevant biomechanical data. In order to develop and validate FEMs and ATDs with improved thoracic injury risk assessment capabilities, it is necessary to generate biomechanical data currently not presented in the literature. Therefore, the purpose of this dissertation is to present novel material, structural, and global thoracic skeletal response data as well as quantify thoracic injury timing in both frontal belt loading and side impact tests using cadaveric specimens.<br>Ph. D.
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Caruthers, William A. "Bisphosphonates and Bone Microdamage." UKnowledge, 2012. http://uknowledge.uky.edu/cbme_etds/4.
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Osteoporosis is a significant healthcare issue due to the increasing elderly population. Bisphosphonates are used to treat osteoporosis by reducing the rate of resorption, increasing bone mineral density (BMD) and thereby reducing fracture risk. Long-term bisphosphonate treatment, however, has been associated with low-energy fractures. Bone microdamage may provide a partial explanation for one of the mechanisms responsible for these fractures since it has been shown to reduce bone toughness, fracture resistance, and bone strength. The goal of this study was to quantify the changes in bone microdamage parameters with the duration of bisphosphonate treatment. This study selected, stained, and histomorphometrically analyzed 40 iliac crest bone biopsies from controls and female patients with osteoporosis treated with bisphosphonates for varying durations (up to 12 years). All subjects were matched for age and low turnover. The results showed that microcrack density and microcrack surface density were significantly greater in patients who took bisphosphonates for at least 5 years compared to those who took bisphosphonates for less than 5 years or not at all. These results reveal novel, clinically relevant information linking microdamage accumulation to long-term bisphosphonate treatment without influences from age or turnover.
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Kluppel, Leandro Eduardo. "Utilização de parafusos absorviveis para fização de enxertos osseos autogenos : estudo histologico em coelhos." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288687.
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Orientador: Renato Mazzonetto<br>Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-08-12T19:06:05Z (GMT). No. of bitstreams: 1
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Previous issue date: 2008<br>Resumo: O objetivo do presente estudo in vivo foi avaliar histologicamente, de forma comparativa, o emprego de parafusos absorvíveis baseados no polímero poli(L-co-D,L ácido lático) 70:30 sintetizado por um laboratório nacional, para fixação de enxertos ósseos autógenos em tíbias de coelhos. Como controle foram utilizados parafusos à base de liga de titânio (Ti-6Al-4V/Grau V) de mesmas dimensões. Para tanto, foram selecionados 15 coelhos adultos, albinos, da raça Nova Zelândia, machos, com idade aproximada de 6 meses e peso variando entre 3,8 e 4,5 kg no momento do procedimento cirúrgico. De cada animal foram removidos 2 enxertos ósseos em espessura total da calota craniana, sendo um deles fixado à tíbia com parafuso absorvível e o outro com parafuso metálico. Os animais foram divididos em 3 grupos, de acordo com os períodos de sacrifício: 3, 8 e 16 semanas pós-operatórias. Após o processamento histológico, as lâminas foram coradas com hematoxilina e eosina e submetidas à análise histológica descritiva em microscopia óptica. Como resultado encontrou-se que o sistema de fixação baseado em polímero apresentou um comportamento histológico bastante semelhante ao sistema metálico. Em ambos os grupos o enxerto encontrava-se incorporado, ocorrendo neoformação óssea em sua interface com o leito receptor. Em nenhum dos grupos foi evidenciado processo inflamatório indesejável ou reação a corpo estranho. Baseando-se nos achados histológicos para o modelo experimental e metodologia empregada, pode-se concluir que o sistema de fixação baseado no polímero poli(L-co-D,L ácido lático) 70:30 é efetivo para a fixação de enxertos ósseos autógenos, com resultados comparáveis ao
materiais à base de liga de titânio.<br>Abstract: The aim of the present in vivo study was to evaluate histologically, by comparative means, the use of resorbable screws based on poli(L-co-D,L lactide) 70:30, manufactured by a brazillian laboratory, used for fixation of autogenous bone grafts in rabbit tibiae. As a control, titanium (Ti-6Al-4V Grade V) screws were used. For this purpose, fifteen white New Zeland male rabbits, with age of 6 months and weight between 3.8 - 4.5 Kg were used. Of each animal, 2 total thickness bone grafts were removed from the cranial vault and one of them was stabilized with resorbable screw while the other was stabilized with the metallic one. Animals were divided in 3 groups, according to the sacrifice period: 3, 8 and 16 week postoperatively. After histological processing, cuts were corated with hematoxilin and eosin and submited to descriptive histological analysis under light microscopy. As a result it was found that the fixation system based on polimer showed a histological behavior similar to the metallic system. For both groups bone graft was incorporated, with the presence of bone neoformation between this and the receptor site. In none of the groups undesirable inflammatory process or foreign body reaction was observed. Based on histological findings and respecting this experimental model it is possible to conclude that that the internal fixation system based on the poli(L-co-D,L lactide) 70:30 polymer is effective for fixation of autogenous bone grafts, offering results that are comparable the titanium fixation systems.<br>Doutorado<br>Cirurgia e Traumatologia Buco-Maxilo-Faciais<br>Doutor em Clínica Odontológica
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Assis, Adriano Freitas de 1977. "Análise mecânica e fotoelástica de sistemas de fixação interna estável utilizados para o tratamento de fraturas subcondilares da mandíbula." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/287892.
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Orientador: Márcio de Moraes<br>Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-08-19T14:44:31Z (GMT). No. of bitstreams: 1
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Previous issue date: 2012<br>Resumo: As fraturas do côndilo mandibular apresentam-se como as injúrias mais comuns ao complexo maxilo-mandibular, contudo ainda existe controvérsia quanto ao seu tratamento. O objetivo neste estudo foi avaliar comparativamente, in vitro, por meio de testes mecânicos e fotoelásticos a fixação de fraturas condilares com diferentes sistemas. Para os testes mecânicos foram utilizadas 60 hemimandíbulas de poliuretano, que foram divididas em 12 grupos com 5 hemimandíbulas cada, sendo dois grupos controle com hemimandíbulas íntegras e mais dois grupos de cada tipo de fixação: duas placas retas do sistema 2,0mm, uma placa trapezoidal do sistema 2,0mm, uma placa trapezoidal com extensão do sistema 2,0mm, uma placa trapezoidal do sistema 1,5mm e uma placa trapezoidal com extensão do sistema 1,5mm. Foram realizados testes de carregamento linear no sentido ântero-posterior e médio-lateral. As médias foram comparados pelo teste de Tukey. As diferenças foram consideradas estatisticamente significantes para p ? 0,05. Para os testes fotoelásticos, foi utilizada uma amostra de 10 hemimandíbulas de resina fotoelástica, sendo duas para cada grupo, na mesma distribuição dos testes mecânicos, submetidas ao carregamento linear nos mesmos sentidos para análise do comportamento e distribuição das tensões. Os resultados indicaram que a fixação com duas placas apresenta maior resistência no sentido ântero-posterior e a fixação com uma placa trapezoidal com extensão apresenta maior resistência no sentido médio-lateral. A análise fotoelástica demonstrou que as tensões são melhores distribuídas nas fixações com placas trapezoidais. De acordo com os resultados foi possível concluir que a extensão posterior das placas trapezoidais aumentou a resistência do sistema de fixação e que a utilização de placa trapezoidal com ou sem extensão posterior foi favorável à distribuição de tensão de maneira mais uniforme<br>Abstract: Fractures of the mandibular condyle are presented as the most common injuries to the maxillo-mandibular complex, however there is still great controversy regarding treatment. The aim of this study was to assess comparatively, in vitro, by mechanical and photoelastic testing, fixation for condylar fractures with different systems. For the mechanical tests 60 polyurethane mandible models were used. They were divided into 12 groups of 5 mandibles, two control groups with intact mandibles and two groups of each type of fixation: two 2.0mm straight plates, a 2.0mm trapezoidal plate, a 2.0mm trapezoidal plate with extension, a 1.5mm trapezoidal plate and a 1.5mm trapezoidal plate with extension. Linear loading tests were carried out in anterior-posterior and medial-lateral directions. Mean and standard deviations were compared by Tukey test. Differences were considered statistically significant at p ? 0.05. For the photoelastic tests, 10 photoelastic mandibles were used, 2 for each group, in the same distribution as the mechanical tests, submitted to linear loading in the same directions to analyze the behavior and distribution of tensile strain lines. The results indicated that the fixation with two plates presented a higher resistance in the anteroposterior direction and fixation with a plate with trapezoidal extension is more resistant towards mediolateral. The photoelastic analysis showed that the strain lines were best distributed when trapezoidal plates were used. According to the results we concluded that the posterior extension of the trapezoidal plates increased the strength of the fixation system, and the use of trapezoidal plate with or without posterior extension was favorable to a more balanced stress distribution<br>Doutorado<br>Cirurgia e Traumatologia Buco-Maxilo-Faciais<br>Doutor em Clínica Odontológica
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Bouyge, Frederic L. "A multiscale model of cancellous bone." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/18206.
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TANAKA, Eiichi, Sota YAMAMOTO, Yoichi AOKI, Takahiro OKADA, and Hiroshi YAMADA. "Formulation of a Mathematical Model for Mechanical Bone Remodeling Process." The Japan Society of Mechanical Engineers, 2000. http://hdl.handle.net/2237/9117.
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Ramesh, Pravin K. "Fabrication and testing of micro-cantilevers in bovine cortical bone." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1316482714.
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Rubin, Pascal. "Hip joint replacement biomechanics and morphometric aspects of the bone-implant system /." Lausanne : EPFL, 1992. http://library.epfl.ch/theses/?nr=1066.
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Yuan, Yuyu. "The differential effects of two critical osteoclastogenesis stimulating factors on bone biomechanics." Connect to this title online, 2009. http://etd.lib.clemson.edu/documents/1252424964/.
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Gerber, Joel M. "Biomechanical Evaluation of Facet Bone Dowels in the Lumbar Spine." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1438959810.
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Mhatre, Devdatt. "Biomechanical Evaluation of Vertebral Augmentation to Compare Biocure Cement with PMMA." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1309390838.
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Martin, Madge Audrey Marie. "Bone remodelling and mechanomics: Bridging organ, tissue, and cell scales to understand bone structure and function." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/203101/1/Madge%20Audrey%20Marie%20Martin%20Thesis.pdf.
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The structure and chemical composition of our bones change over the course of life through a multi-physical process called bone remodeling. In particular, one cells living in the pores of bone tissue sense variations in their environment. In this context, we focus on mechanomics, the description of the action of mechanics on biological tissues.
We explore several approaches to mechanistic modeling of bone remodeling: one addresses the question at the cellular level, the other at the organ level. We finally propose a unifying theory combining biochemical and mechanical aspects. Finally, we introduce a clinical application to adolescent idiopathic scoliosis.
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Kerner, Jan. "Patient specific computer modelling of bone changes around orthopaedic implants." Thesis, Imperial College London, 1999. http://hdl.handle.net/10044/1/7912.
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KUMMARI, SEETHA RAMUDU. "Experimental and Computational Evaluation of Microscopic Tissue Damage and Remodeling Cavities in Trabecular Bone." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1300920008.
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Rodrigues, Danillo Costa 1981. "Análise mecânica e fotoelástica de quatro diferentes métodos de fixação em fraturas de corpo mandibular." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288760.
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Orientador: Roger William Fernandes Moreira<br>Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-08-24T15:32:49Z (GMT). No. of bitstreams: 1
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Previous issue date: 2014<br>Resumo: O propósito do presente estudo foi avaliar comparativamente, através de teste de carregamento linear e análise fotoelástica, quatro métodos de fixação em fraturas simuladas em corpo de hemimandíbulas de poliuretano e resina fotoelástica. O trabalho foi dividido em quatro grupos: O grupo I, foi fixado com duas placas do sistema 2,0mm, uma na zona de tensão e outra na zona de compressão mandibular. No grupo II, utilizou-se uma placa do sistema 2,0mm na zona central da mandíbula e uma barra de Erich na zona dentada. O grupo III, foi fixado com uma placa do sistema 2,4mm na zona de compressão e uma barra de Erich na zona dentada. E no grupo IV, foi empregada uma placa do sistema 2,0mm na zona de tensão e uma placa do sistema 2,4mm na zona de compressão. Os métodos de fixação utilizados em cada grupo foram semelhantes em ambos os testes. Testes de carregamento linear foram realizados por meio da máquina para ensaio universal mecânica Instron®. Os valores foram analisados pelo teste de Shapiro-Wilk. Em seguida, foi aplicada a Análise de Variância (ANOVA), Kruskal-Wallis e posteriormente, o teste de Tukey e Mann-Whitney com correção de Bonferroni. Para a análise do teste fotoelástico, as hemimandíbulas em resina fotoelástica foram fotografadas quando a máquina de ensaio registrou o deslocamento final de 3mm e as franjas formadas no substrato foram avaliadas de forma qualitativa. Os resultados dos testes mecânicos indicaram que o grupo II apresentou menor resistência, seguido dos grupos I, IV e III. O teste fotoelástico confirmou a maior formação de tensão no grupo de menor resistência mecânica. Dessa forma concluiu-se que em fraturas lineares de corpo de mandíbula a utilização de placa do sistema 2,4mm apresentou maior resistência e que o emprego de apenas uma placa do sistema 2,0mm na zona central apresentou maior tensão<br>Abstract: The purpose of this study was to evaluate comparatively through linear load testing and photoelastic analysis, four methods of fixation in simulated fractures on polyurethane hemimandibles body and photoelastic resin. The study was divided into four groups: Group I was fixed with two plates of 2.0 mm system, one in the tension zone and another in compression zone. In Group II, it was used a 2.0 mm plate in the neutral zone and an Erich bar. Group III was fixed with a 2.4 mm plate in the compression zone and an Erich bar. The group IV was employed a 2.0 mm plate in tension zone and a 2.4 mm plate in the compression zone. The fixation methods used in each group were similar in both tests. Linear load testing was performed using an Instron® mechanical universal testing machine. After the tests, the values were analyzed by the Shapiro-Wilk test, Analysis of Variance (ANOVA), Kruskal -Wallis test and subsequently the Tukey test, and Mann-Whitney test with Bonferroni correction. For the analysis of photoelastic test, the hemimandibles were photographed in photoelastic resin when the testing machine recorded the final displacement of 3mm and the fringes formed on the substrate were evaluated qualitatively. The results of mechanical tests indicated that the group II had lower resistance, followed by the groups I, III and IV. The photoelastic test confirmed the increased formation of tension in the group of lower mechanical strength. Thus, it was concluded that in linear mandibular body fracture using the system board 2.4 mm presented more resistance and the use of only one 2.0 mm plante in the central area of the mandible showed higher tension<br>Doutorado<br>Cirurgia e Traumatologia Buco-Maxilo-Faciais<br>Doutor em Clínica Odontológica
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Joo, Won. "CROSS-MODAL EFFECTS OF DAMAGE ON MECHANICAL BEHAVIOR OF HUMAN CORTICAL BONE." Case Western Reserve University School of Graduate Studies / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=case1126285139.
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Cavalieri-Pereira, Lucas 1982. "Resistência de quatro técnicas de fixação utilizadas no tratamento das fraturas subcondilares = estudo in vitro em mandíbulas de poliuretano." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/287846.
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Orientador: Alexandre Elias Trivellato<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-08-18T13:54:21Z (GMT). No. of bitstreams: 1
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Previous issue date: 2011<br>Resumo: A fratura do côndilo mandibular usualmente requer tratamento cirúrgico com emprego de fixação interna estável. O objetivo neste estudo foi avaliar comparativamente a resistência de quatro técnicas de fixação utilizadas no tratamento de fraturas subcondilares. Foram empregadas 84 mandíbulas sintéticas, 147 placas retas e 546 parafusos. As mandíbulas foram submetidas a um seccionamento simulando uma fratura subcondilar esquerda e fixadas com quatro técnicas utilizando-se das placas de 2,0 e 1,5 mm, que deram origem a doze grupos experimentais, cada um com 7 mandíbulas. Chamou-se de grupos G1, G5 e G9, aqueles fixados com uma placa reta de 4 furos do sistema 2,0 mm. Os grupos G2, G6 e G10, foram fixados com uma placa de 4 furos dos sistema 2,0 mm e uma placa de 3 furos do sistema 1,5 mm. Grupos G3, G7 e G11, aqueles fixados com duas placas 2,0 mm, sendo a anterior de 3 furos; Grupos G4, G8 e G12, aqueles fixados com duas placas 2,0 mm de 4 furos. Cada sistema foi submetido ao teste de resistência com aplicação de carga no sentido súpero-inferior em máquina de ensaio EMIC, modelo DL2000. Em G1, G2, G3 e G4 a aplicação de carga foi no primeiro molar do lado da fratura simulada (MF). Em G5, G6, G7 e G8, no primeiro molar contralateral à fratura simulada (MC). Em G9, G10, G11 e G12, entre os incisivos centrais (I). Foram mensurados valores de carga para os deslocamentos de 1 mm, 2 mm e 5 mm. Os resultados obtidos no teste de resistência foram comparados utilizando análise de variância (ANOVA), seguido do teste de Tukey com nível de significância de 5%. Verificou-se valores de carga menores no grupo tratado com uma placa de 4 furos do sistema 2,0 mm, nos deslocamentos de 1 e 2 mm, com aplicação de carga em MF. Pode-se concluir que a utilização do sistema de fixação com duas placas proporciona maior resistência<br>Abstract: Fractures of mandibular condyles usually require surgical treatment with steady employment internal fixation. The aim in this study was to evaluate the resistance of four fixation technique used in the treatment of subcondylar fractures. Were employed 84 synthetic jaws, 147 straight plates and 546 screws. The jaws underwent a sectioning simulating a left subcondylar fracture and fixed with four techniques using 2.0 mm and 1.5 mm plates, which gave rise to twelve experimental groups, each with 7 mandibles. Drew G1, G5 and G9, those set with single straight plate 4-holes. Groups G2, G6 and G10, were fixed with one 2.0 mm system plate 4-holes and one 1.5 mm system plate 3-hole. Groups G3, G7 and G11, were fixed with two plates 2.0 mm, which more anterior had 3-hole. Groups G4, G8 and G12, those fixed with two plates 2.0 mm with 4-hole. Each system was subjected to the test of resistance with load application superior-inferior on testing machine EMIC model DL2000. In G1, G2, G3 and G4 the implementation of load was the first molar side fracture simulated (MF). In G5, G6, G7 and G8 were in the first molar contralateral to the simulated fracture (MC). In G9, G10, G11 and G12 was between the central incisors (I). Load values were measured for displacement from 1 mm, 2 mm and 5 mm. Results obtained in the test of resistance were compared using analysis of variance (ANOVA), followed by Tukey test with a significance level off 5%. There was minor loads value in the group treated with a plate of 4-hole system 2.0 mm, in displacements of 1 and 2 mm, with application in MF. Can conclude that the use of the fixation system with two plates provide greater resistance<br>Mestrado<br>Cirurgia e Traumatologia Buco-Maxilo-Faciais<br>Mestre em Clínica Odontológica
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田中, 英一, Eiichi TANAKA, 創太 山本 та ін. "骨の力学的再構築課程に対する数理モデルの定式化". 日本機械学会, 2000. http://hdl.handle.net/2237/9115.
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