Distraction osteogenesis is a recently developed option for surgical correction of the craniofacial discrepancy but there are few studies that look at the long-term effect of the relapse phenomenon. This study was conducted to look at the bone and muscle response at different consolidation and remodelling periods. Thirty ten-week-old Merino lambs were subjected to this current study. The surgically created defect was performed on the experimental side (right) by superficial masseter myectomy and a condylectomy. The lambs showed a midline shift to the affected side three months later. Marker screws were placed on both sides of the mandible to examine the adjustment of the vertical and horizontal dimension of the mandible. In this present study, the left side was used as the control. The affected mandible was surgically corrected using a vertical ramus distraction osteogenesis protocol. The latency period was 7 days where the device was inactive. Distraction was then performed at 1 mm per day until the distracted gap was 10 mm on a radiograph. Initially, the sheep were divided into 8 groups but later the groups were refined into 6 groups for statistical analysis; Group 1: Immediately post distraction Group 2: Consolidation 2 months and remodelling 1 month Group 3: Consolidation 3 months Group 4: Consolidation 3 months and remodelling 1 month Group 5: Consolidation 3 months and remodelling 2 months Group 6: Consolidation 4 months A ‘hemifacial microsomia like’ defect was successfully created and it was then corrected using vertical ramus distraction. Cephalometric examination showed that the vertical height was significantly increased after the distraction was completed. Examination of the bone and muscle was performed to look at the adjustment of bone structure in relation to relapse. The bone investigation was conducted using radiological analysis, histological analysis and direct measurement of the vertical screws at pre-distraction and at sacrifice as well as histomorphometric analysis. The radiological examination was conducted using cephalometric analysis of the distance between marker screws on both experimental and control sides. Bone histology was investigated on the middle and posterior position of the experimental side. The histomorphometric analysis was conducted using Quantiment analysis software. The muscle responses and adaptation were investigated by measuring: the weight of the masseter and medial pterygoid muscles; length between 6 different points (4 landmarks); cross section and thickness of masseter muscles by ultrasound and by histopathological examination of both masseter and medial pterygoid muscles on the experimental and the control sides. The distracted bone showed a completion of maturation after a three month consolidation period. Bone formation was shown to continue after longer consolidation periods. A two-month consolidation period was insufficient time for the bone to consolidate and stable, as there was evidenced of relapse during this period. There was no increased in muscle mass after distraction. The distraction altered the length of anterior and posterior planes and the size of cross sectional area and thickness of origin and middle level of masseter muscles. There were no changes in the length of the middle and oblique planes and the cross sectional area of the insertion of the masseter muscle. The distracted muscle adapted well after a longer consolidation and remodelling period but was sensitive to any surgical procedure such as device removal. The adjustment was observed to continue within the first month after surgical removal of device. The weight, length of planes, cross section and thickness was temporarily reduced on the experimental side but continued to improve and stabled during the second month after removal of the device. The first month after device removal also showed that histopathological activity was increased after both 2 and 3 month consolidation periods. Importantly, muscle histopathology was back to almost normal activity after the second month of device removal, following a 3 month consolidation period. This study showed that it was possible to create a ‘hemifacial microsomia like’ defect in very young lambs. The defect was then successfully corrected by a vertical distraction osteogenesis procedure. It was also shown that the sufficient time for the device to be fixed in place (consolidation period) was 3 months or longer as the bone and muscle was stable after that period of time. Results from this investigation have important implications to the management of similar conditions in humans. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1346836 / Thesis (Ph.D.) - University of Adelaide, School of Dentistry, 2008.

Σκοπός της διπλωματικής αυτής εργασίας είναι η μελέτη ρομποτικής διάταξης οστεογένεσης και πιο συγκεκριμένα η μελέτης της δυναμικής και ο έλεγχος αυτής. Πιο αναλυτικά, τα κεφάλαια που ακολουθούν πραγματεύονται τα ακόλουθα: θα παρουσιαστεί γενικά ο μηχανισμός της οστεογένεσης από ιατρικής πλευράς, καθώς επίσης και οι διάφορες διατάξεις με τις οποίες πραγματοποιείται η διατατική οστεογένεση. Στη συνέχεια θα παρουσιάσουμε τις κινηματικές και δυναμικές εξισώσεις της πλατφόρμας Stewart. Το τελευταίο μέρος αποτελεί και το πειραματικό μέρος της παρούσας εργασίας δηλαδή τον έλεγχο της συγκεκριμένης διάταξης μέσω του SimMechanics toolbox του πακέτου MatLab. Στο παράρτημα παρουσιάζονται τα αποτελέσματα των πειραμάτων με μορφή διαγραμμάτων. / Distraction osteogenesis and simulation of stewart platform on Simulink.

No description available.

Bone Morphogenetic Protein 2 (BMP2) is a growth factor needed to initiate fracture repair and is involved in the differentiation of progenitor cells to the osteochondral lineage. Osteogenesis and angiogenesis are coupled processes, however the mechanism by which these processes are coupled and the role that BMP2 plays in coupling these processes is not well understood. In distraction osteogenesis, a bone regeneration model mediated by mechanical distraction of an osteotomy, BMP2 expression was primarily associated with blood vessels. Therefore, transgenic mice were used to conditionally delete BMP2 expression (BMP2-cKO) in smooth muscle cells during distraction osteogenesis to identify the role of BMP2 in osteogenesis and angiogenesis. Vessel formation was characterized by vascular perfusion of animals with a barium-gelatin solution, which was used as a radiographic contrast agent that allowed vessel formation to be quantified by micro-computer assisted tomography (µCT). Using the same transgenic mice to label those cells in which BMP2 had been deleted, histological analysis was performed to confirm the targeting specificity of the BMP2-cKO. µCT analysis showed less bone formation occurred in the BMP2-cKO animals compared to controls. The µCT analysis further showed vessel volume and thickness were decreased in BMP2-cKO animals at both day 17 and 31, suggesting that there is a relationship between BMP2 and vessel size. Vessel number was greater in controls than the BMP2-cKO animals at day 17, however the BMP2-cKO animals had a larger vessel number than the number by day 31. Histological analysis confirmed knockout of BMP2 expression in smooth muscle cells, as well as in skeletal muscle and chondrocytes. These results suggest the importance of BMP2, not only in bone formation, but also in vessel morphogenesis.

Made available in DSpace on 2014-06-11T19:27:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-07-06Bitstream added on 2014-06-13T20:57:09Z : No. of bitstreams: 1 oliveira_ca_me_arafo.pdf: 995320 bytes, checksum: fe65fd0d87c661122e78f571d2bfe20f (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O objetivo deste trabalho foi avaliar, por meio de modelos de estudo, os efeitos da Distração Osteogênica Médio-Sagital da Mandíbula (DOMM) no arco mandibular de pacientes que utilizaram aparelhos dento-suportados. A amostra consistiu de 14 pacientes (5 do gênero masculino e 9 do gênero feminino) com idades variando de 13 a 19 anos e média de idade de 15,74 ± 1,89 anos no início do tratamento. Modelos de estudo foram obtidos de cada paciente no início do tratamento (T1), três meses após a DOMM (T2) e no momento da remoção dos aparelhos fixos (T3). Os dados foram submetidos à Análise de Variância e teste complementar de Duncan e demonstraram que todas as dimensões transversais aumentaram com a DOMM, o comprimento do arco não sofreu alteração estatisticamente significante, o perímetro do arco aumentou e o Índice de Irregularidade diminuiu consideravelmente, refletindo a correção do apinhamento ântero-inferior. Os dentes posteriores apresentaram maior expansão das cúspides do que das cervicais, indicando uma possível inclinação causada pelo uso de aparelho dento-suportado. Todas a medidas mostraram algum grau de recidiva, que variou de 2,8% a 8,84%. Os achados desta pesquisa permitiram concluir que a DOMM é uma alternativa eficaz para o tratamento do apinhamento associado à deficiência transversal de mandíbula. / The purpose of this study was to evaluate the effects of Mandibular Symphyseal Distraction Osteogenesis (MSDO) with a tooth-borne distraction device, analysed in dental casts. The sample included 14 patients (5 males and 9 females) between 13 and 19 years of age, with a mean age of 15,74 ± 1,89 years at the start of treatment. Dental casts were obtained at the start of treatment (T1), three months after distraction (T2) and at the end of treatment, when fixed appliances were removed (T3). The data were analysed statistically using ANOVA and Duncan’s test and showed that all transverse widths increased, arch length was maintained, arch perimeter increased significantly and Irregularity Index decreased, showing the correction of crowding. Molars and premolars had a disproportionate pattern of distraction, characterized by greater cusps expansion than cervical one. This pattern might be caused by the use of a tooth-borne distraction device. All the measurements demonstrated evidence of relapse, that varied from 2,8% to 8,84%. The findings of this study indicate that MSDO is an efficient treatment alternative for dental crowding and mandibular transverse deficiency.

No / Little has been written about the functional outcome of patients treated with bone transport to reconstruct a distal tibial defect. The aim of this study was to investigate the functional capabilities of patients who had undergone reconstruction with distraction osteogenesis for the treatment of a distal tibial defect in one lower limb. At least eighteen months after completion of treatment, eight patients who had no pain and were able to walk and climb stairs without difficulty performed isometric ankle plantar flexion maximum voluntary contractions while the electromyographic activity of the tibialis anterior and triceps surae muscles was simultaneously recorded. Seven of the patients also underwent gait analysis. Data for the involved limb were compared with those collected for the contralateral limb. During gait, stance time (p = 0.01), the plantar flexion angular displacement and peak moment developed during the second half of stance (p < 0.046), and the amount of ankle power generated (p = 0.02) were significantly decreased in the involved limb compared with the contralateral limb. Similar decreases were observed in the plantar flexion (p = 0.01) and dorsiflexion (p = 0.01) maximum voluntary contractions and the corresponding electromyographic activity (p = 0.01). These results suggest that adaptive changes had occurred at the level of the transported muscles, which affected both routine and maximal effort capabilities. These findings contribute to our understanding of the functional limitations of patients who have undergone bone transport with its obligatory shortening of muscle length.

Background: Transverse mandibular discrepancies are often overlooked during orthodontic treatment. MSDO is a treatment to address this issue, but much debate exists over the long-term implications on the temporomandibular joint (TMJ). Few studies have sample sizes sufficient to draw clear conclusions about the impact of MSDO on TMJ health. Materials and Methods: This study evaluated private practice records including 49 MSDO patients and 57 traditionally-treated controls. The subjects were assessed by TMD exams that evaluated jaw pain and discomfort using visual analog scales, range of motion for opening, right and left lateral, and protrusive movements, and the presence of clenching, bruxism, clicking, crepitus, and pain on TMJ and muscle palpation. Results: No significant changes between the groups were noted during treatment or follow-up. Conclusions: Compared to controls, MSDO patients did not experience any increase in TMD symptoms. Distraction and control patients were not significantly different in any of the categories.

Introdução: Os pacientes com fissura labiopalatina, com deficiências maxilares muito severas, geralmente são tratados com avanço maxilar por meio da osteotomia tipo Le Fort I. Entretanto, a distração osteogênica com o distrator externo rígido (RED) pode funcionar como uma alternativa terapêutica para a correção da discrepância esquelética. Proposição: O objetivo do presente estudo é avaliar os efeitos do avanço maxilar por meio da distração osteogênica com distrator externo rígido (RED), associada à osteotomia tipo Le Fort I, em pacientes com fissura transforame unilateral ou bilateral, quanto à quantidade de avanço maxilar e à sua estabilidade a médio e longo prazo. Materiais e Métodos: Para a realização deste estudo longitudinal e retrospectivo, foram usadas telerradiografias em norma lateral de 9 pacientes (6 do gênero masculino e 3 do gênero feminino), onde 4 apresentaram fissura transforame unilateral e 5 apresentaram fissura transforame bilateral, submetidos ao avanço maxilar por meio da distração osteogênica com distrator externo rígido (RED). Foram estabelecidos três tempos de avaliação: fase pré-distração (T1), fase pós-distração imediata (T2) e fase pós-distração controle, com o mínimo de 1 ano após a finalização da distração (T3). A demarcação dos pontos cefalométricos e a obtenção das medidas das variáveis cefalométricas foram realizadas através do software Dolphin Imaging®, versão 11.5. Para a análise dos resultados, o teste estatístico ANOVA de medidas repetidas foi utilizado, adotando-se o nível de significância de 5%. Resultados: No início da distração, a idade média foi de 14 anos e 4 meses (idade mínima de 9 anos, e máxima de 21 anos). O período médio de distração foi de 18 dias, com uma média de ativação no distrator de 1,0mm/dia. O avanço médio da maxila medido em LVR-A, em T2, foi de 15,6mm (p<0,001), com recidiva não estatisticamente significante de 21,79% (p=0,102), em T3. O aumento médio de SNA, em T2, foi de 14,8º (p<0,001), com recidiva não estatisticamente significante de 18,90% (p=0,130), em T3. Os valores médios das medidas SN.GoMe, 1.PP e IMPA não apresentaram variação estatisticamente significante (p>0,05) entre T1, T2 e T3. Conclusão: A terapia de distração osteogênica para avanço maxilar com o RED mostrou ser eficiente, com aumentos significantes das medidas cefalométricas lineares e angulares relacionadas ao avanço maxilar, demonstrando efeito predominantemente esquelético, e estabilidade no período pós-distração médio (T3) de 1 ano e 8 meses. / Introduction: Patients with unilateral and bilateral cleft lip and palate, with significant maxillary hypoplasia are commonly treated with maxillary advancement by Le Fort I osteotomy. However, distraction osteogenesis with a rigid external distraction (RED) device can function as an alternative option for treatment of the skeletal discrepancy. Purpose: The aim of this study is to assess the effects of maxillary advancement by distraction osteogenesis using a rigid external distraction (RED) device, associated with the Le Fort I osteotomy in patients with unilateral or bilateral cleft lip and palate, as the amount of maxillary advancement and their stability in the medium and long term. Materials and Methods: To perform this retrospective longitudinal study, lateral cephalograms of 9 patients (6 males and 3 females) were used, where 4 had unilateral cleft lip and palate and 5 had bilateral cleft lip and palate, who underwent maxilla advancement by distraction osteogenesis with RED device. Three stages of evaluation were established: pre-distraction (T1), immediate post-distraction (T2) post-distraction control, with a minimum of 1 year after completion of distraction (T3). The anatomic landmarks and measurements of cephalometric variables were performed by using the Dolphin Imaging® version 11.5 software. To evaluate the results, the ANOVA test for repeated measures was used, adopting a significance level of 5%. Results: At the start of distraction, mean age was 14 years and 4 months (minimum age 9 years old and maximum of 21 years old). The mean distraction period was 18 days, with a mean rate of distractor activation in 1.0 mm / day. The mean maxillary advancement in LVR-A, at T2, was 15.6 mm (p<0.001), with no statistically significant relapse of 21.79% (p=0.102) at T3. The SNA angle increase, at T2, was 14.8º (p<0.001), with no statistically significant relapse of 18.90% (p=0.130), at T3. The mean values of SN.GoMe, IMPA and 1.PP measures showed no statistically significant variation (p>0.05) between T1, T2 and T3. Conclusion: The therapy of distraction osteogenesis for maxillary advancement with RED is efficient, with significant increases in the linear and angular cephalometric measurements related to the maxilla advancement, demonstrating predominantly skeletal effect and stability in mean post-distraction period (T3) of 1 year and 8 months.

Orientador: Luiz Gonzaga Gandini Júnior / Banca: Ana Claudia Moreira Melo / Banca: Ary dos Santos Pinto / Resumo: O objetivo deste trabalho foi avaliar, por meio de modelos de estudo, os efeitos da Distração Osteogênica Médio-Sagital da Mandíbula (DOMM) no arco mandibular de pacientes que utilizaram aparelhos dento-suportados. A amostra consistiu de 14 pacientes (5 do gênero masculino e 9 do gênero feminino) com idades variando de 13 a 19 anos e média de idade de 15,74 ± 1,89 anos no início do tratamento. Modelos de estudo foram obtidos de cada paciente no início do tratamento (T1), três meses após a DOMM (T2) e no momento da remoção dos aparelhos fixos (T3). Os dados foram submetidos à Análise de Variância e teste complementar de Duncan e demonstraram que todas as dimensões transversais aumentaram com a DOMM, o comprimento do arco não sofreu alteração estatisticamente significante, o perímetro do arco aumentou e o Índice de Irregularidade diminuiu consideravelmente, refletindo a correção do apinhamento ântero-inferior. Os dentes posteriores apresentaram maior expansão das cúspides do que das cervicais, indicando uma possível inclinação causada pelo uso de aparelho dento-suportado. Todas a medidas mostraram algum grau de recidiva, que variou de 2,8% a 8,84%. Os achados desta pesquisa permitiram concluir que a DOMM é uma alternativa eficaz para o tratamento do apinhamento associado à deficiência transversal de mandíbula. / Abstract: The purpose of this study was to evaluate the effects of Mandibular Symphyseal Distraction Osteogenesis (MSDO) with a tooth-borne distraction device, analysed in dental casts. The sample included 14 patients (5 males and 9 females) between 13 and 19 years of age, with a mean age of 15,74 ± 1,89 years at the start of treatment. Dental casts were obtained at the start of treatment (T1), three months after distraction (T2) and at the end of treatment, when fixed appliances were removed (T3). The data were analysed statistically using ANOVA and Duncan's test and showed that all transverse widths increased, arch length was maintained, arch perimeter increased significantly and Irregularity Index decreased, showing the correction of crowding. Molars and premolars had a disproportionate pattern of distraction, characterized by greater cusps expansion than cervical one. This pattern might be caused by the use of a tooth-borne distraction device. All the measurements demonstrated evidence of relapse, that varied from 2,8% to 8,84%. The findings of this study indicate that MSDO is an efficient treatment alternative for dental crowding and mandibular transverse deficiency. / Mestre

Distraction osteogenesis (DO) is a surgical procedure in which applied strain stimulates new bone growth; however, the underlying mechanisms by which bone cells respond to load are still uncertain. An organ culture model of DO was developed and validated by using linear distraction on the femoral shafts of 5 day old Wistar rats. Two loading regimes were utilized: distracting the bones for 2 hrs on day 1 (GRP I); distracting the bones for 2 hrs on days 1, 3, and 5 (GRP II). After 1 week in culture, the bones were compared to unloaded contralateral controls and assessed for changes. Structural, dimensional, massing, micro-CT, areal, and viability properties were obtained from testing. Relative to paired controls, distracted bones demonstrated an increase in failure load (9.15% GRP I, 18.85% GRP II), increase in stiffness (31.28% GRP I, 53.21% GRP II), increases in areal and polar moments of inertia, and viability (6.21% GRP I, 13.02% GRP II). Our results suggest that DO can be modeled successfully with an organ culture, and continued use of this system will help to gain insight into the mechanisms and pathways by which distraction osteogenesis occurs.