Orientador: Francisco Haiter Neto / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-21T22:06:49Z (GMT). No. of bitstreams: 1 Gamba_ThiagodeOliveira_M.pdf: 1982337 bytes, checksum: 59e9e9eb3c74854ff87b24acbb1ed82a (MD5) Previous issue date: 2013 / Resumo: O objetivo no presente estudo foi verificar se medidas antropológicas realizadas em mandíbulas, por meio de imagem de Tomografia Computadorizada de feixe cônico (TCFC), podem detectar o dimorfismo sexual em uma população brasileira. Adicionalmente, criar uma fórmula, a partir destas medidas para determinação do sexo. Para isso, foi selecionada uma amostra de 159 imagens de TCFC de indivíduos de uma população brasileira (74 homens e 85 mulheres), com idade variando de 18 a 60 anos. As imagens foram analisadas por 5 avaliadores, que realizaram seis mensurações: comprimento do ramo mandibular em altura (CR), comprimento da base mandibular (CBM), menor comprimento do ramo mandibular em largura (MCR), ângulo goníaco (AG), distância intercondilar (DIC) e distância intergoníaca (DIG), em reconstruções 3D de TCFC. Após quinze dias, as mensurações foram repetidas com 25 % da amostra. Para análise estatística, foi aplicada a Correlação Intraclasse na avaliação intra e interexaminador, Análise de Variância (ANOVA) para comparação entre os valores médios das mensurações presentes e equações binárias de Regressão Logística foram criadas para determinação do sexo. As mensurações evidenciaram valores do sexo masculino superiores aos do feminino, exceto na variável MCR que não apresentou diferença estatisticamente significante entre os sexos. As medidas com maiores índices dimórficos foram: DIG, CR, DIC, e AG. Associando estas quatro medidas obteve-se uma precisão de 95,1% na determinação do sexo, assim, foi possível concluir que a fórmula desenvolvida no presente estudo pode ser utilizada para identificação do sexo na prática forense / Abstract: The aim of this study was to determine whether anthropological measurements taken in jaws through image cone beam CT (CBCT) could aid in detecting sexual dimorphism in a Brazilian population. Additionally, this study was aimed at creating a formula from these measurements for sex determination. Subjects (n=159) involved a Brazilian population (74 men and 85 women), aged 18-60 years. The CBCT images were analyzed by 5 reviewers, who performed six measurements in the analysis of sexual dimorphism: Ramus length (R-L); Gonion-gnathion length (G-G-L); Minimum ramus breadth (M-R-Br); Gonial angle (G-A); Bicondylar breadth (Bic-Br); and Bigonial breadth (Big-Br), reconstructions in 3D CBCT. The measurements were repeated with 25% of the sample 15 days after the first evaluation for statistical analysis, the intraclass correlation was used to evaluate intra- and inter-examiners, the Analysis of Variance (ANOVA) to compare the mean values and the binary logistic regression equations were created to determine the sex. The measurements showed higher values for males, except for M-R-Br, showing no statistically significant difference between genders. The measurements with the highest rates were dimorphic: Big-Br, R-L, Bic-Br and GA. When the four variables were associated, an accuracy of 95.1% in sex determination was observed. In conclusion, the formula developed in this study can be used for sexual differentiation in forensic settings / Mestrado / Radiologia Odontologica / Mestre em Radiologia Odontológica

The master’s thesis deals with issues belonging to the field of dental biomechanics, specifically the mechanical interaction of dental implants with the bone tissue of the mandible. The thesis focuses on the stress-strain analysis of the mandible with the implant inserted in different positions, with a different angle relative to the occlusal plane. The solution is performed by computational modeling using the finite element method. The geometry model of mandible was created based on CT images. The aim of the master’s thesis was also to compare the influence of the choice of the material model of cancellous bone tissue on the resulting stress-strain states of the mandible with the dental implant. Three material models of cancellous bone tissue were created - two homogeneous material model and a heterogeneous material model, which was based on CT image data. The work also investigates the effect of rotation (+5° or -5°) of implants in basic positions on the resulting stress-strain states. The stress-strain analysis showed that position and rotation has a greater effect on the stress and strain of bone tissue and implant than the chosen material model of cancellous bone tissue.

Bilateral mandibular ostectomies were performed between premolars 3 and 4 in 10 adult canine specimens. A type I external fixator incorporating a full interdental pin was placed stabilizing a 0.5 cm fracture gap. Four different pin configurations were tested in dorsoventral bending five separate times on each of the ten mandibles: 1) intact mandibular bodies with fixator; 2) ostectomized mandibular bodies and complete fixator; 3) ostectomized mandibular bodies with the caudal pins of the rostral fragment cut; 4) ostectomized mandibular bodies with all pins of the rostral fragment cut. The full interdental pin remained intact in all configurations. Total stiffness and gap stiffness were then determined for each fixation geometry on a materials testing machine. The mean total stiffness(Nm/rads) for the four configurations was 1) 1543.6, 2) 301.6, 3) 290.5, 4) 267.0. The mean gap stiffness(Nm/rads) for the right hemimandible was: 2) 2041.1, 3) 1763.5, 4) 1679.9. The mean gap stiffness of the left hemimandible was: 2) 2110.8, 3)1880.1, 4)1861.1. There was no gap stiffness for the first configuration since a fracture gap was not present. Two-way ANOVA was performed on the gap stiffness and the total stiffness. There was a significant decrease in total stiffness between intact mandibles and ostectomized mandibles regardless of external fixator configuration. However, there was not a significant difference in total stiffness or gap stiffness among the different external fixator configurations applied to ostectomized mandible. External fixator configurations with only the full interdental pin engaging the rostral fragment were as stiff as configurations which had two or four additional pins in the rostral fragment for the applied loads. External fixators for rostral mandibular fractures may be rigidly secured with rostral fragment implants applied extracortically avoiding iatrogenic trauma to teeth and tooth roots. / Master of Science

>Magister Scientiae - MSc / Introduction: A common complication of poorly managed mandible fractures is infection. There is a consensus amongst clinicians in treating infected mandible fractures in an immediate setting. The approach includes drainage of the purulent discharge, debridement of the fracture, removal of teeth in the fracture line and immediate fixation. Fixation can be load bearing or load sharing in nature. Although clinicians advocate for the use of a reconstruction load bearing plate, a double miniplate fixation could be an alternative. Aim: The aim is to assess the outcomes of double miniplate osteosynthesis in the immediate management of infected mandible fractures Material and method: A prospective cohort study was conducted. The sample size was 20 (n =20). Infections were treated with an incision and drainage and the fractures fixated with a double miniplate fixation system. Pain scores, fracture union, fracture stability and surgical times were measured. Follow–up visits included one week, six weeks and three months respectively.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / The study evaluated the effects of a mandibular repositioning appliance (MRA) in patients with obstructive sleep apnea. The MRA was designed to hold the mandible anteriorly in an attempt to maintain a patent airway. Eleven subjects completed a full-night polysomnogram wherein their normal sleep was recorded half the night without the appliance (control) and the other half with the appliance (test). The sequencing of test and control halves was randomly assigned to avoid bias. After seven subjects were tested with the MRA, the MRA was modified for four additional patients by placing anterior vertical elastics (MRA*) to minimize the opening of the mandible. The skeletal and soft tissue changes with both appliances were analyzed using lateral cephalometric radiographs. The MRA was found to have no significant effect on the obstructive sleep apnea patients as a group. Individual response to the appliance varied from noticeably worse to marked improvement. Subject #2A exhibited the reduction of a moderate-to-severe apnea (Apnea-hypopnea index 55.92) to a clinically acceptable level (Apnea-hypopnea index 9.57) with appliance wear. The treatment was considered successful. Significant cephalometric changes with appliance wear were increased lower facial height, a superiorly positioned hyoid bone relative to the mandibular plane, and a decreased posterior airway space. No cephalometric measurement could accurately predict the outcome of the treatment, and posterior airway space, commonly measured in sleep research, was not reliable. The mandibular repositioning appliance was effective in treating a small percentage of individuals with obstructive sleep apnea. A polysomnogram was needed to quantitatively measure the effectiveness of treatment. Under no circumstance should a subjective evaluation by the patient or the clinician be used to assess treatment results. Further investigation is required to evaluate the long-term effectiveness of this treatment. Periodic follow-up sleep studies are required for any patient treated with this appliance until more long term studies are completed.

Indiana University-Purdue University Indianapolis (IUPUI) / It has been proposed that jaw deformation during function may be a contributor to supraosseous tooth eruption. This could be through a transient pressure gradient in the flexed bone and/or tension in the PDL fibers produced by socket deformation. Thus, the purpose of this study was to determine if forces applied to a fresh frozen canine mandible can lead to occlusal displacement of a tooth. Seven hemisected canine mandibles (14 specimens) were used to test this hypothesis. A force cycle (10 N to 100 N to 300 N) was applied by a Bionix testing machine (MTS TM Systems Corp., Minneapolis, Minn.) to the mandible in three point bending. Digital radiographs were taken at each change in force level using computer digitized radiography (CDR, TM Schick Technologies, Inc., Long Island City, N.Y.). By measuring the relative movement of metal markers (1 mm steel balls) placed into the mandible and the crown of the 2nd premolar, the amount of tooth eruption was calculated. With cyanoacrylate cement (Archer® Instant Bonding Adhesive, Tandy Corp, Ft. Worth, Texas) injected into the PDL space of the same tooth, the test was repeated one week later. These "ankylosed" teeth served as controls. The eruption distances were compared between the experimental and the ankylosed teeth by means of repeated measures analysis of variance. The only significant occlusal displacement was noted as the force was initially raised to 100 N (21.7 ± 40.6 μm). Due to the possible breakdown of the cyanoacrylate cement, the ankylosed teeth also showed evidence of eruption with the continued application of force. Although significant eruption was noted, the displacements were very small. PDL degradation, viscoelastic behavior, measurement of small displacements, limited resolution radiography, and two dimensional analysis are contributing factors to the uncertainty of the results. Further investigation is required to determine if jaw deformation during function is a viable mechanism leading to the occlusal displacement of teeth.

Thesis (M.S.)--University of Michigan, 1987.

Thesis (M.S.)--University of Michigan, 1973.

Thesis (M.S.)--University of Michigan, 1979.