Thesis (M. Cl. D.)--University of Western Ontario, 1997. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Introduction: This vertical malocclusion has the potential of causing functional and esthetic impairment, impacting patients´ quality of life negatively. The long-term stability of anterior open bite surgical-orthodontic treatment is an important and controversial issue. A variety of factors such as surgery type, surgery fixation, and the anteroposterior discrepancy is related to and can influence long-term overbite stability. The controversy of stability arises in the inherent difficulty of collecting a homogeneous sample, with considerable sample size and adequate long-term followup, leading the current literature to an inconclusive status. Therefore this thesis aimed to test 2 null hypotheses: 1- There is no difference in the long-term stability of the surgical-orthodontic correction of anterior open bite when comparing Le Fort I to 4-piece segmental Le Fort I osteotomies. 2- To test the null hypothesis that there is no difference in the long-term stability of the surgical-orthodontic correction of anterior open bite when comparing Class II to Class III patients. Materials and Methods: The sample of the first investigation comprised the lateral cephs of 29 open bite subjects treated with 1-piece Lefort I osteotomy compared to the lateral cephs of 24 open bite subjects treated with 4-piece Lefort I osteotomy; in both groups Class I, II and III subjects were included. The groups were matched regarding age and were compared with t-tests. To test the second null hypothesis, lateral cephs of 21 Class II open bite subjects were compared to lateral cephs of 25 Class III open bite subjects. Overbite changes were compared at 3-time points: T1 (pretreatment), T2 (posttreatment) and T3 (follow-up) by using t-test. Overbite clinical stability percentage at T3 was assessed with the chi-square test. Results: In 1-piece Le Fort I Group 65.52% of patients presented with clinically significant overbite stability, while in 4-piece Group 83.33% remained stable in the long-term, however it was not statistically significant. In Class II Group 57.14% of patients presented with clinically significant overbite stability, while in Class III Group 88% remained clinically stable, and it was statistically significant. Conclusions: The first null hypothesis regarding maxillary segmentation was accepted because there was no significant intergroup difference regarding the percentage of clinically stable patients. The type of fixation seems to influence the long-term stability of open bite surgical-orthodontic correction more than maxillary segmentation. The second null hypothesis was rejected because clinical stability of Class II malocclusion open bite surgical-orthodontic treatment was significantly smaller than in Class III malocclusions. / Introdução: A estabilidade em longo prazo do tratamento orto-cirúrgico da mordida aberta anterior é um assunto relevante e controverso. Esta má oclusão vertical tem o potencial de causar importantes alterações tanto funcionais quanto estéticas, impactando negativamente a qualidade de vida dos pacientes. Vários fatores, como o tipo de cirurgia, a fixação cirúrgica e a discrepância ântero-posterior, estão relacionados e podem influenciar a estabilidade da sobremordida em longo prazo. A controvérsia na estabilidade surge na dificuldade inerente de coletar uma amostra homogênea, com um tamanho de amostra considerável e acompanhamento adequado em longo prazo, levando esse assunto na literatura atual a um status inconclusivo. Portanto, esta tese teve como objetivos testar 2 hipóteses nulas: 1- Não há diferença na estabilidade em longo prazo da correção orto-cirúrgica da mordida aberta anterior ao comparar as osteotomias tipo Le Fort I com e sem segmentação maxilar. 2- Não há diferença na estabilidade em longo prazo da correção orto-cirúrgica da mordida aberta anterior ao comparar pacientes com má oclusão de Classe II e Classe III. Materiais e Métodos: A amostra da primeira investigação compreendeu as telerradiografias de 29 indivíduos com mordida aberta tratados por osteotomia Lefort I sem segmentação maxilar, às quais foram comparadas às telerradiografias laterais de 24 indivíduos com mordida aberta tratados por osteotomia Lefort I com segmentação maxilar; pacientes Classe I, II e III foram incluídos. Os grupos foram compatibilizados pela idade e foram comparados com testes t e qui-quadrado. Para testar a segunda hipótese nula, telerradiografias laterais de 21 indivíduos com mordida aberta e má oclusão de Classe II foram comparadas às telerradiografias laterais de 25 indivíduos com mordida aberta e má oclusão de Classe III. As alterações do overbite foram comparadas em três tempos: T1 (pré-tratamento), T2 (pós-tratamento) e T3 (longo-prazo) usando o teste t. A taxa de estabilidade clínica em T3 foi avaliada com teste de qui-quadrado. Resultados: No Grupo Le Fort I sem segmentação maxilar 65,52% dos pacientes apresentaram estabilidade clínica da sobremordida, enquanto que no Grupo Le Fort I com segmentação maxilar, 83,33% mantiveram-se estáveis em longo prazo, porém essa diferença não se apresentou estatisticamente significante. No Grupo Classe II, 57,14% dos pacientes permaneceram clinicamente estáveis, enquanto que no Grupo Classe III, a porcentagem clínica de estabilidade foi de 88%, e a diferença apresentou significância estatística. Conclusões: A primeira hipótese nula em relação à segmentação maxilar foi aceita porque não houve diferença estatisticamente significante entre os grupos em relação à porcentagem de pacientes clinicamente estáveis. O tipo de fixação parece influenciar a estabilidade em longo prazo da correção orto-cirúrgica da mordida aberta mais do que a segmentação maxilar. A segunda hipótese nula foi rejeitada porque a estabilidade clínica do tratamento orto-cirúrgico da mordida aberta em pacientes com má oclusão de Classe II foi significativamente menor do que nos pacientes com má oclusão de Classe III.

O objetivo principal deste trabalho foi determinar, por meio de avaliação em fotografias frontais sorrindo, a distribuição dos tipos principais de Classe II, subdivisão. Secundariamente, estes subgrupos foram comparados com um grupo de oclusão normal, para investigar a ocorrência de assimetria dentoesquelética, utilizando-se radiografias submentonianas e póstero-anteriores. O grupo experimental consistiu de 44 indivíduos que apresentavam má oclusão de Classe II, subdivisão, com idade média de 15,3 anos. O grupo controle consistiu de 30 indivíduos que apresentavam oclusão normal, com idade média de 22,42 anos. Todos apresentavam os dentes permanentes superiores e inferiores, em ambos os arcos dentários, até os primeiros molares e que não haviam sido submetidos a tratamento ortodôntico. A Classe II, subdivisão do tipo 1 apresenta uma coincidência da linha média dentária superior com a linha média facial e desvio da linha média dentária inferior. O tipo 2 apresenta características opostas. Duas examinadoras realizaram uma avaliação subjetiva das fotografias frontais. Para a avaliação da simetria, medidas de diferenças relativas da posição espacial de pontos dentários e esqueléticos bilaterais foram obtidas nas radiografias submentoniana e pósteroanterior. Utilizou-se o teste t independente para a comparação das assimetrias dentoesqueléticas entre os subgrupos de Classe II, subdivisão, tipos 1 e 2 com o grupo de oclusão normal. Os resultados demonstraram que 61,36% dos casos de Classe II, subdivisão foram do tipo 1; 18,18% foram do tipo 2 e 20,45% foram considerados duvidosos. Os dois subgrupos de Classe II, subdivisão apresentaram um grau de assimetria esquelética semelhante ao grupo de oclusão normal. Portanto, concluiu-se que os principais componentes que contribuem para a relação ântero-posterior assimétrica na Classe II, subdivisão, tipos 1 e 2 são dentoalveolares. / The primary objective of this study was to determine, by means of frontal photographic evaluation, the distribution of the two main types of Class II subdivision malocclusions. Secondarily, a comparison of the degree of dentoskeletal asymmetries in these two types was performed with a group of normal occlusion using submentovertex and posteroanterior radiographs. The experimental group consisted of 44 untreated Class II subdivision malocclusion subjects with a mean age of 15.3 years. The control group consisted of 30 subjects with normal occlusion with a mean age of 22.42 years. All possessed a full complement of permanent teeth up to the first molars and had not been submitted to orthodontic treatment. Type I Class II subdivision malocclusion presents a coincidence of the maxillary dental midline with the facial midline and a deviation of the mandibular midline. Type II presents the opposite characteristics. Evaluation of the frontal photographs was performed by means of a subjective evaluation by two examiners. In the submentovertex and osteroanterior radiographs, symmetry was assessed by measuring the relative difference in spatial position of dentoskeletal landmarks between right and left sides. Independent t tests were used to compare the dentoskeletal asymmetries of Types I and II with the normal occlusion group. Results demonstrated that 61.36% presented a Type I, 18.18% presented a Type II Class II subdivision malocclusion and 20.45% were considered undefined. The two subgroups of Class II subdivision malocclusion presented a similar degree of skeletal asymmetry as the normal occlusion group. Therefore, it was concluded that the primary contributors for the asymmetric anteroposterior relationship in types 1 and 2 of Class II subdivision malocclusions are dentoalveolar.

Magister Scientiae Dentium - MSc(Dent) / This paper has attempted to describe the prenatal development of the mandible in humans and ita postnatal growth. The various theories of how this growth occurs have been described including the historical work by Brash, the' classical theory', .. which includes a section on the controversy regarding the term' growth centre' and its application to the mandibular condyle. Bjork's investigations using the implant method have been covered. This method allowed him to superimpose the mandibles in a longi tudinal growth study with more ease and accuracy than was formerly possible.Note that no mention is made in this paper of the error due to magni~cation changes in the radiographs resul~ing from the growth itself. Enlow's theory ,including his ideas on relocation,cortical drift,reversal etc. based on the morphology of the mandible are covered. The functional theory of Moss'which has many supporters and is perhaps one of the strongest theories is included with a further section on the role function plays The other main theory described is the theory of arcial growth is covered by Ricketts. The chin is a characteristic of Man and a short section will be found about its development Nowadays we are using prediction of the growth of an individual as an intgral part of our treatment plan in orthodontics .I have attempted to describe the structural features of acephalo metric radiograph which are our guidelines for prediction I have included at the end a short part about investigations using hormones to study their role in development.This only scratches the surface of the many hormonal studies carried out but serves to show another side of research concerning the development of the mandible.

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A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Medicine, Johannesburg, 2018 / Introduction: The hallux valgus interphalangeus (HVI) deformity has a common association with hallux valgus and hallux rigidus. The radiographic measurement of the hallux valgus interphalangeus is formed by the angle between the long axes of the proximal and distal phalanges. The normal value for this angular deformity in the coronal plane is less than 10 degrees. The reliability of measuring the hallux interphalangeal angle has not been verified as yet .The purpose of this study is to analyse the intra- and inter-observer reliability of measurements of the interphalangeal angle by orthopaedic surgeons. This study is going to be the first study to evaluate the reliability and reproducibility of the hallux valgus interphalangeal angle. Methods: Twenty one X-ray prints (images) of the weight bearing foot constituted a set. Three such sets were sent to each evaluator at four week intervals. Sixteen qualified orthopaedic surgeons were asked to measure the hallux interphalangeal angle of all twenty one X-ray images at three different occasions. After all three sets were measured, data was retrieved and statistically analysed to determine the incidence of inter- and intra-observer variability and reliability in the measurement of the hallux interphalangeal angle. Results: Reproducibility of the hallux interphalangeal angle measurement was assessed using three categories which included the ability to measure the same angle three times and achieve: three degrees or less, five degrees or less, more than five degrees. The intra-observer reliability was found to be 5 degrees and less in 75.2% of participants and for the inter-observer reliability was 61.2%. The researcher did not find significant correlation between the surgeons’ level of experience with respect to the reliability of measurement of the hallux interphalangeal angle. Conclusion: The reliability and reproducibility of measurement of the hallux interphalangeal angle is low. The level of experience of the surgeon does not improve this reliability. / XL2018

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Apart from associated genes, a candidate causative gene NTF4 was screened and two novel putative mutations (Gly157Ala and Ala182Val) detected, likely accounting for 0.29% of POAG. In the exploration of new POAG genes, two functional candidates CNTF and SPARC were screened and excluded. / Differential association profiles were found for SNPs in/near CAV1, CAV2, CYP46A1, LMX1B, PLXDC2, TLR4, TMTC2, ZP4 and 2p16.3. SNPs at CAV1, CAV2, TLR4 and 2p16.3 were associated with POAG, whilst SNPs around other genes were unlikely to be risk factors for the disease, at least in Chinese. TLR4 rs7037117 was associated with HTG in southern Chinese (P=0.0016, OR=2.72, recessive model). SNP rs1533428 at 2p16.3 showed an age-specific association of with late-onset POAG (age at diagnosis >60 years; P=1.14x10-5, OR=2.02, dominant model) but not with juvenile- and adult-onset POAG. Moreover, rs1533428 formed a joint effect with rs7037117 to confer stronger risk to HTG (P=2.8x10 -4, OR=4.53). Besides, rs4236601 near the CAV1 and CAV2 genes was confirmed as a risk factor for POAG and another two protective SNPs rs6975771 and rs959173 were identified; moreover, that the risk and protective alleles were located in different haplotypes suggested multiple roles of the genes. / Glaucoma is a group of degenerative optic neuropathies and the leading cause of irreversible blindness worldwide. Primary open-angle glaucoma (POAG) is a major type of glaucoma in most populations. It is classified into high-tension glaucoma (HTG) and normal-tension glaucoma (NTG) according to the level of intraocular pressure. POAG has complex etiology. It could be monogenic or caused by multiple risk factors. At least 22 linkage loci have been mapped, with 3 genes (MYOC, OPTN, and WDR36 ) identified. Also, more than 30 susceptibility genes have been reported, many of which, however, remain unverified. / In the mapping of the causal gene at GLC1N, a truncation mutation c.1090delT in the MEGF11 gene was found to be cosegregated with glaucoma in the GLC1N-linked pedigree. Subsequent identification of c.1090delT in an unrelated JOAG patient supported that it is a disease-causing mutation. The identification of four splice-site mutations (IVS17+2insT, IVS17-4C>G, IVS17-2A>G and c.2472A>C) exclusively in patients provided further evidence supporting MEGF11 as a causative gene for POAG. Mutations in this gene likely account for approximately 1% of POAG or 2% of JOAG. / This thesis describes our work on the identification of new POAG genes by using a 3-tiered strategy: (1) to identify new genetic profiles of variants around the CAV1, CAV2, CYP46A1, LMX1B, NTF4, PLXDC2, TLR4, TMTC2, ZP4 genes and the 2p16.3 locus; (2) to evaluate CNTF and SPARC as disease genes for POAG; and (3) to map the causal gene at the GLC1N locus for juvenile-onset POAG (JOAG). / Totally 1645 unrelated participants were enrolled, including a Hong Kong cohort of 281 HTG, 311 NTG and 248 controls, a Shantou cohort of 102 HTG, 28 NTG and 298 controls and, a Beijing cohort of 177 HTG and 200 controls. Also involved were members of the GLC1M-linked Philippine pedigree and the GLC1N-linked Hong Kong pedigree with JOAG, which have been previously described. / Chen, Lijia. / Adviser: Chi Pui Pang. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 185-210). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Fan Baojian. / "June 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 101-126). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.