Thesis (Ph.D. )--School of Dentistry. University of Missouri--Kansas City, 2006. / "A dissertation in oral biology and molecular biology and biochemistry" Advisor: Jian Q. Feng. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed Sept. 12, 2008. Includes bibliographical references (leaves 111-121). Online version of the print edition.

Thesis (M.S.)--University of Michigan, Ann Arbor, 1977. / Typescript (photocopy). Includes bibliographical references (leaves 42-45). Also issued in print.

Thesis (M.S.)--University of Michigan, Ann Arbor, 1977. / Typescript (photocopy). eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 42-45).

Thesis--Bergen. / Extra t.p. with thesis statement inserted. Includes bibliographical references.

Thesis--Bergen. / Extra t.p. with thesis statement inserted. Includes bibliographical references.

Orientador: Sérgio Swain Müller / Resumo: Com o objetivo de se comparar as propriedades mecânicas do ligamento cruzado anterior (LCA), dos 10 mm do terço central do ligamento da patela (LP), e do tendão do músculo semitendíneo triplicado (STT) do mesmo doador, foram realizados ensaios de tração em material obtido de 19 cadáveres humanos. A idade dos doadores foi de 40 11 anos (18-55 anos), sendo 15 (78,9%) masculinos e 4 (21,1%) femininos, 12 brancos (63,1%) e sete negros (36,9%); 10 (52,6%) joelhos do lado esquerdo e 9 (47,4%) do lado direito. Foi obtida a área de secção dos corpos de prova para que, além das propriedades estruturais, também fossem avaliadas as propriedades materiais. Além do diagrama carga-alongamento, foram estudadas as seguintes variáveis: carga máxima (N), alongamento absoluto (mm) e específico (%) na ruptura, limite de proporcionalidade (N) e respectivos alongamentos, tensão na carga máxima(MPa), módulo de elasticidade (MPa), energia na ruptura (Nm) e energia por área (Nm/m2) . A análise estatística comparativa entre os três materiais mostrou que o LP foi superior ao LCA e ao STT, na carga máxima, tensão na carga máxima, módulo de elasticidade, energia, energia por área e limite de proporcionalidade, caracterizando comportamento de maior estabilidade e rigidez. O LCA e STT apresentaram semelhança com relação à carga máxima, tensão na carga máxima, limite de proporcionalidade e módulo de elasticidade. No STT observou-se valor maior em comparação ao LCA para energia e energia por área, na carga máxima. O STT alongou-se mais que o LCA e LP na ruptura e no limite de proporcionalidade. Não houve associação entre idade e carga máxima, tensão, energia e módulo de elasticidade no LCA, LP e STT. Houve associação entre carga máxima e área de secção no LCA e STT. Concluiu-se que o LP e STT têm comportamento mecânico distinto e que o perfil de ambos justifica a utilização como substitutos do LCA. / Abstract: The material obtained from 19 human cadavers was submitted to traction-testing with the purpose of comparing the mechanical properties of the 10mm-central third of the patellar ligament (PL), triplicate semitendinosus muscle (TSM) and anterior cruciate ligament (ACL). Mean donor age was 40 11 years; 12 whites (63.1%) and 7 blacks (36.9%); 10 (52.6%) left knees and 9 (47.4%) right knees. The cross-sectional area of the test specimens was obtained so that, besides structural properties, material properties could also be evaluated. In addition to the load-strain diagram, the following variables were studied: ultimate load (N), absolute strain (mm) and relative strain (%) at failure load, yield point (N) and its respective strains, stress at ultimate load (MPa), modulus of elasticity (MPa), energy at failure (Nm) and energy per area (Nm/m2). Comparative statistical analysis of the materials revealed that PL was superior to ACL and TSM in ultimate load, stress at ultimate load, modulus of elasticity, energy, energy per area and yield point, thus featuring a behavior of greater stability and rigidity. ACL and TSM showed similar ultimate load, stress at ultimate load, yield point and modulus of elasticity. In TSM, energy and energy per area at ultimate load were higher than in ACL. Strain was greater in TSM than in ACL and PL at failure load and yield point. No association was observed between age and ultimate load, stress, energy and modulus of elasticity in ACL, PL and TSM. Ultimate load and cross-sectional area are associated in ACL and TSM. In conclusion, PL and TSM present distinct mechanical behaviors and their profiles justify their use as ACL replacements. / Doutor

Indiana University-Purdue University Indianapolis (IUPUI) / This is the first in a series of experiments designed to investigate the effect of local and systemic factors on osteoblast histogenesis in rats. A soft diet is an experimental means thought to decrease the overall mechanical loading (a local factor) on the masticatory apparatus. Eighteen Sprague-Dawley rats were divided into three equally sized groups: 1) an experimental group, which was maintained on a soft paste diet; 2) a control group, pair fed with the experimental group; and 3) a control group fed ad libitum. Both control groups continued to eat standard Purina rat chow pellets. Twenty-three days later all animals were injected subcutaneously with 1.0 μCi/ g tritiated thymidine and sacrificed one hour later. The maxillae of the animals were dissected and sectioned. The periodontal ligament (PDL) of the mesial surface of the mesial root of the first molar was analyzed microscopically 110 μm above and below the mid root area. Nuclear size was used to determine the stage of osteoblast differentiation. The labeling index was used to determine the proliferative activity of the cells. The distance of cells from the nearest major blood vessel (NMBV) was measured and the cells were grouped into one to four extravascular zones. For each zone, cell density was determined. PDL widths were measured to evaluate tooth function. If osteogenesis is due primarily to stress and strain on bones, then rats maintained on the soft diet should show a decreased labeling index, increased number of A and A' cells, decreased number of C and D cells, and an unaltered vascularly-oriented cell density gradient. The number of osteoblastic precursor cells (A and A' cells) close to blood vessels should increase relative to the number of preosteoblastic cells (C and D) further from the vessels. Also, the width of the PDL space in the soft diet rats should be narrower since their function was decreased. The results of this study did not support the hypothesis that a decrease in masticatory stress and strain within the rat periodontal ligament due to softened dietary consistency reduces osteoblast histogenesis. No differences were seen in the PDL widths or the vascularly-oriented cell density gradient between groups. High levels of A+A' cells were seen paravascularly for all groups, and their relative numbers decreased as one moved away from the blood vessel into a lower cell density area, supporting previous studies. No differences were seen in the fractional distribution of A+A' cells or C+D cells between groups, as was hypothesized, except for a higher level of A+A' cells in the pair fed group across all zones. This latter finding was probably due to physiologic variation and the small sample sizes used in this study. Decreased masticatory stress and strain due to a softened diet did not reduce osteoblast histogenesis. Further research needs to investigate systemic factors which may influence bone formation.

Thesis (M.D.S.)--Dept. of Dentistry, Faculty of Dentistry, University of Adelaide, 1990. / Spine title: A T.E.M. investigation of extrusion and R.C.T. on the marmoset periodontal ligament. Typescript (Photocopy). Includes bibliographical references (leaves 163-191).

Thesis (M.S.)--University of Michigan, 1965.

Thesis (M.S.)--University of Michigan, 1985.