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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Three-dimensional assessment of facial deformities and their surgical outcomes

Jayaratne, Yasas Shri Nalaka January 2011 (has links)
Data on the three?dimensional (3?D) morphology of normal faces and facial deformities as well as objective techniques for evaluating postoperative changes are currently unavailable. With the advent of stereophotography and cone?beam CT (CBCT), it is possible to acquire 3?D images of soft and hard tissues of the maxillofacial complex. A series of studies were conducted aimed at 1) establishing 3?D facial anthropometric norms for Hong Kong young adults, 2) determining 3?D facial anthropometric features in skeletal Class II and III deformities, 3) characterizing the oropharyngeal space in Class II and III skeletal deformities, 4) exploring clinical applications of 3?D colour maps, 5) establishing a non?invasive technique for estimating serial volume changes and 6) creating virtual craniofacial models by fusing 3?D photographs and CBCT images. Study 1: A stereophotographic system was used to capture 3?D images of 103 Hong Kong Chinese young adults with normal balanced faces. An anthropometric analysis protocol with linear, angular and proportional measurements was developed to establish a normative database and quantify dysmorphology. The Hong Kong Chinese norms were distinct from Caucasians, especially with regard to ocular and nasal measurements. Facial height and nasolabial measurements differed significantly between Hong Kong males and females. Study 2: Anthropometric analyses of 3?D facial images from 41 skeletal Class II and 43 Class III subjects were performed. The Class II subjects had increased lower facial height compared with Class III, who had longer total facial heights and narrower faces. While Class II deformity primarily resulted from mandibular deficiency with a normal maxilla, Class III presented as combined midfacial hypoplasia and mandibular hyperplasia. Study 3: Anthropometric characteristics of the oropharygeal space in skeletal Class II and III were evaluated using 62 CBCT scans. The retroglossal (RG) and retropalatal (RP) volumes and average cross sectional areas were significantly larger in Class III than Class II skeletal deformity. The RP compartment was larger but less uniform than the RG compartment in both Classes. Study 4: 3?D photographs or CBCT images acquired at two different time points were superimposed using a common unaffected area. 3?D colour maps were generated depicting distance differences between superimposed images in a graphical format. These maps were used as an objective tool for treatment planning and assessing outcomes after orthognathic surgery, bimaxillary distraction and facial trauma. Study 5: 3?D photogrammetry was employed for planning soft tissue expansion (STE) and transplantation of a vascularised scapular flap in hemifacial microsomia. This technique facilitated the identification of extent and degree of tissue deficiency, selection of the appropriate tissue expander, monitoring volumetric changes during STE and estimation of the free flap dimensions. Study 6: 3?D facial photographs and CBCT scans of 29 subjects were merged to create virtual craniofacial models with natural surface texture. Accuracy was assessed with 3?D colour maps and Root Mean Square (RMS) error. The CBCT and 3?D photographic data were integrated while minimizing average RMS error to 0.441mm. These virtual composite craniofacial models permitted concurrent 3?D assessment of bone and soft tissue. / published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy
2

The Australian Craniofacial Unit, 1975-1996 / David John David.

David, David John, 1940- January 1997 (has links)
Includes bibliographical references. / 2 v. : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Sets out the principles of craniofacial surgery and how they have been utilised to form the Australian Craniofacial Unit. Progress of the organisation is mapped over twenty one years using selected published papers in which the author has in some way contributed to the development of teaching, research and service in craniofacial surgery. Papers are grouped so as to show the progress made in the areas of trauma, the craniosynostoses, rare craniofacial clefts, frontal ethmoidal meningoencephaloceles, craniofacial tumours, as well as research and development. / Thesis (M.D.)--University of Adelaide, Dept. of Surgery, 1999
3

Psychological adjustment of patients with dentofacial deformity beforeand after orthognathic surgery

Wu, Yuen-fan, Lina., 胡婉芬. January 2012 (has links)
Dentofacial deformities have an adverse impact on functional as well as psychological wellbeing. Being highly visible, they may lead to a host of psychological problems particularly in youths and young adults as concerns about bodily identity and integrity are likely to be most prominent. Body image and self-esteem have been noted to play an important role in adjusting to disfigurement. Those who opted for corrective orthognatic surgery with realistic expectations were found to have a higher level of satisfaction with the outcome of the surgery. In contrast, undue and unrealistically positive aspirations towards the surgery are implicated in increased post-operative psychological difficulties. This study aimed to systematically document the variability of psychological adjustment and study the predictors of well-being in individuals with dentofacial deformity after orthognathic surgery. Seventy patients pending to go through orthognathic surgery were recruited from a university based dental hospital. Assessments of the patients’ overall psychological condition and adjustment towards their dentofacial deformity were conducted with standardized questionnaires and compared with similar assessment conducted with control subjects. The patients’ motivations for orthognathic surgery, psychological well-being, as well as expectations on the outcomes of surgery were studied through individually conducted psychological assessment interviews. Patients were re-assessed at 6 and 12 months after surgery on their level of satisfaction toward the outcome of surgery as well as to gauge possible changes in their psychological condition. There was no excess of significant psychopathology in patients with dentofacial deformity compared to the normal control group. However, as predicted, people with dentofacial deformity were more dissatisfied with their facial attractiveness. They also have more problems in interpersonal sensitivity. In the patient group, functional impairment or disability was a lesser concern compared to body image and presentation. Improvement of physical attractiveness was a strong underlying motivation for treatment. Longitudinal data on patients’ level of satisfaction with the treatment outcomes and perceived benefits associated with the improved facial esthetics will be further analyzed in the light of their underlying psychological vulnerabilities or resilience. The results are expected to cast light on factors that may affect patients’ satisfaction with the treatment. The results of the study confirmed that dissatisfaction with facial appearance prompted acceptance of surgery despite its associated discomfort and hazards. The findings of the study are expected to be useful in better informing clinical psychological interventions with aims of enhancing adjustment and forestalling psychological morbidity through early intervention with individuals coping with facial disfigurement. / published_or_final_version / Psychiatry / Doctoral / Doctor of Philosophy

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