Digital Commons Network^™

Debt And Stress Amongst Orthodontic Residents, Timothy Renison

Electronic Thesis and Dissertation Repository

Background: The cost of education to become an orthodontist has increased significantly over recent years which has led to an increase in debt of graduating orthodontists.

Aim: This paper aims to assess whether debt amongst orthodontic residents in North America is associated with their stress levels, attitudes towards debt, financial literacy and mathematics anxiety.

Materials and Methods: Web-based software was used to fabricate a questionnaire, based on previously validated scales, in which respondents were asked questions regarding their debt levels, stress levels, attitudes towards debt, financial literacy and math anxiety.

Results: A total of 101 orthodontic residents completed the online …

In Vitro Analyses Of The Contributions Of The Hip Capsule To Joint Biomechanics, Emma Donnelly

Electronic Thesis and Dissertation Repository

Optimal management of the hip capsule during arthroscopic surgery has not been established. The impact of incisions made to the capsule during minimally invasive procedures on joint biomechanics, and whether repair provides any benefit, continue to be debated. The effectiveness of capsular repair to restore native kinematics may be insufficient. Therefore, a better understanding of joint behavior during various capsule conditions is needed. A new robotic system was used to analyze the effect of progressive capsulotomy incision and repairs on the behavior of a normal hip within range of motion (ROM) limits with respect to the intact joint. Complete repairs …

The Role Of Gsk3 Alpha And Beta In Embryonic Craniofacial Development, Harman Jassar

Electronic Thesis and Dissertation Repository

Background: The GSK-3 genes (Gsk3a and Gsk3b) have been known to affect many cellular processes and signaling pathways some of which are implicated in the growth and development of the craniofacial skeleton.

Aim: The purpose of this study was to assess the effect of chondrocyte-specific deletion of Gsk3a and Gsk3b on the size of the mandible and craniofacial skeleton in embryonic mice.

Materials & Methods: Mice were bred to generate cartilage-specific Gsk3a and Gsk3b KO mice. On embryonic day 18.5 (E18.5) the offspring were gathered by caesarian section. Whole mount skeletal staining was completed on the specimens using …

The Effect Of Pigmentation On Latex And Non-Latex Orthodontic Elastics, Dustin Wilson

Electronic Thesis and Dissertation Repository

Background: Intraoral Elastics have been widely used in Orthodontics for well over 100 years. Changes in material composition, manufacturing and addition of color to elastics has shown to effect force levels over time.

Aim: The purpose of the study was to determine the effect of pigmentation on force levels and their degradation over time in both Latex and Non-Latex orthodontic intraoral elastics.

Materials & Methods: Groups consisted of elastics in Latex from American Orthodontics in both natural and four different colors, American Orthodontics Non-Latex in natural, Ormco Latex in both natural and four different colors, Auradonics Latex in both natural …

Evidence Of An Antigen Presenting Cell Phenotype In Granular Cell Tumours, Benjamin J W A Rogala

Electronic Thesis and Dissertation Repository

Granular Cell Tumours (GCTs) are rare subepithelial lesions that are believed to develop from Schwann cells and are characterized by large polygonal cells with abundant lysosomes. Pilot studies from our laboratory showing unexpected HLA-DR immunoreactivity in GCTs lead us to hypothesize that GCTs have an antigen presenting cell (APC) phenotype.

To test our hypothesis, we assessed immunoreactivity of GCT lesions to APC phenotype markers, including CD68, HLA-DR, CD163, CD40 and CD11c. In addition, we assessed markers of neural crest cell (NCC) origin S100, SOX10, NSE and GAP43. Samples subjected to these studies included 23 cases of GCTs and 10 cases …

Mood And Anxiety Disorders, Measurement, And Migrant Groups In Ontario, Jordan Edwards

Electronic Thesis and Dissertation Repository

Our objectives were to: (1) evaluate the current literature on the epidemiology of mood or anxiety disorders among migrant groups; (2) assess how current tools for measuring mood or anxiety disorders at the population level influence our understanding of the epidemiology by a) analyzing the concordance between two commonly used population measures, and b) using a Bayesian analysis to create a combined estimate using both measures; (3) estimate the prevalence and effects of potential risk factors on the prevalence of mood or anxiety disorders among first-generation migrant groups compared to the general population in Ontario. We conducted a systematic review …

A Clinically Representative Rat Model Of Hip Hemiarthroplasty, Adam Dm Paish

Electronic Thesis and Dissertation Repository

Joint replacement is an increasingly common surgery with over 130,000 procedures performed annually in Canada. Although joint replacement surgery is highly successful, implants do not last a lifetime, and often have to be replaced via costly revision surgeries. Before innovations aimed at extending the life of implants are applied to the clinic, testing must be performed in animal models. Clinically representative small-animal models of joint replacement would be ideal in the initial stages of research and development, due to ease of handling and low costs, but few such models have been established in the literature. Thus, we describe the development …

Metal Additive Manufacturing For Fixed Dental Prostheses, Mai El Najjar

Electronic Thesis and Dissertation Repository

The use of additive manufacturing (AM) in dentistry has gained momentum in recent years. However, high initial costs and uncertainty surrounding the quality of AM products are considered barriers to their use. This research compared dental substructures fabricated by AM versus conventional casting and milling.

Cobalt-chromium alloy rectangular bars and three-unit bridge substructures were fabricated by AM, casting or milling. Bars manufactured by AM exhibited superior flexural strength, shear bond strength of porcelain coating, and Vickers hardness. Bridge substructures fabricated by AM showed similar flexural stiffness to cast, similar flexural loads at failure to milled and cast, and overall accuracy …

Utilization Of Healthcare By Immigrants In Canada: A Cross-Sectional Analysis Of The Canadian Community Health Survey, Nisanthini Ravichandiran

Electronic Thesis and Dissertation Repository

Immigrants to Canada face unique barriers to health care, which leads to inequities in the utilization of health care. Lower utilization of health care by immigrants to Canada is associated with the deteriorating health of individual immigrants as well as costs to the health care system. The existing literature suggests that time since immigration is an important predictor for utilization of healthcare for Canadian immigrants. This thesis uses Andersen and Newman’s Framework of Health Service Utilization and data from the 2015-2016 Canadian Community Health Survey to examine health care utilization among immigrants in Canada. The objectives were: (1) To examine …

Nurses' And Midwives' Experiences As Mentors In A Clinical Mentorship Program In Rwanda, Marie Chantal Murekatete

Electronic Thesis and Dissertation Repository

In Rwanda, the provision of maternal and child health care is often hindered by gaps in health care providers’ (HCP) knowledge and skills, and the management of pregnancy-related complications in health facilities. These factors contribute to maternal and child mortality rates (MMR). To help respond to the gaps, the Training Support and Access Model (TSAM) project implemented a practice-based clinical mentorship program (CMP) in the Northern and Southern provinces of Rwanda that involved mentors supporting mentees’ professional development to strengthen nurses’ and midwives’ capacity to provide knowledgeable maternal and child health care.

This qualitative descriptive study aimed to explore nurses’ …

Machine Learning For Prostate Histopathology Assessment, Wenchao Han

Electronic Thesis and Dissertation Repository

Pathology reporting on radical prostatectomy (RP) specimens is essential to post-surgery patient care. However, current pathology interpretation of RP sections is typically qualitative and subject to intra- and inter-observer variability, which challenges quantitative and repeatable reporting of lesion grade, size, location, and spread. Therefore, we developed and validated a software platform that can automatically detect and grade cancerous regions on whole slide images (WSIs) of whole-mount RP sections to support quantitative and visual reporting. Our study used hæmatoxylin- and eosin-stained WSIs from 299 whole-mount RP sections from 71 patients, comprising 1.2 million 480μm×480μm regions-of-interest (ROIs) covering benign and cancerous tissues …

Optimizing Fecal Microbiota Transplantations For Therapeutic Use Beyond Clostridioides Difficile Infection, Laura J. Craven

Electronic Thesis and Dissertation Repository

Fecal microbiota transplantation (FMT) is an emerging and effective therapy for the treatment of recurrent Clostridioides difficile infection. Members of the gut microbiome have been implicated in other diseases and FMT has been considered as a potential therapy. Two such conditions include non-alcoholic fatty liver disease (NAFLD) and multiple sclerosis (MS), both of which involve increased small intestinal permeability believed to contribute to the development and disease progression. One of the aims of this project was to determine if FMT could be safely used in patients with NAFLD and MS to improve health outcomes. Before starting the clinical studies, optimal …

A Coaching And/Or Education Intervention Targeting Physical Activity And Nutrition Behaviours In Parents With Overweight/Obesity And Their Children, Shazya Karmali

Electronic Thesis and Dissertation Repository

The purpose of this dissertation is to provide a detailed overview of, findings from, and experiences participating in a 3-month randomized controlled trial (RCT) targeting obesity-related behaviours in parents with overweight/obesity (body mass index [BMI] ≥ 25 kg/m²) and their children (2.5-10 years old, any weight; N = 50 dyads). A concurrent mixed methods study comprised of an RCT and descriptive qualitative design was utilized. Parent-participants received Co-Active Life Coaching (CALC) and webinar-based health education (intervention) or education only (control). To address the dissertation’s purpose, Chapter II provides a detailed methodological account of the program, including rationale and …

Survey Of Canadian Orthodontists Regarding Orthodontic Miniscrew Usage, Leah A. Van Sant

Electronic Thesis and Dissertation Repository

Purpose: To obtain information on the clinical utilization of orthodontic miniscrews (OMSs) among orthodontists in Canada

Methods: Web-based software was used to fabricate a questionnaire in which respondents were asked questions regarding their usage of OMSs in their clinical practice. The survey consisted of between 11 and 39 questions, depending on the respondents’ answers. The survey was distributed via email to the 353 active Canadian members of the American Association of Orthodontists (AAO).

Results: A total of 82 Canadian orthodontists responded to the survey, for a response rate of 23.2%. Among them, 65.8% currently used miniscrews in their clinical practice. …

Evaluating The Utility Of Protein Biomarker, S100a7, And Diagnostic Test, Straticyte, In Predicting The Progression Of Oral Dysplasia, Lachlan Mclean

Electronic Thesis and Dissertation Repository

Five-year survival of oral cancer has remained relatively unchanged despite advancements in treatment, mostly because diagnosis is often made at an advanced stage of disease. The progression of dysplasia to oral cancer often follows a stepwise progression. Histopathology is considered the ‘gold standard’ for diagnosing dysplasia and lesions at a high risk of progression to oral cancer, but lends itself to subjectivity. The protein biomarker, S100A7, in oral dysplasia and squamous cell carcinoma has shown some predictive value for the transformation of dysplasia to cancer. Straticyte, a diagnostic test utilizing S100A7 to predict the probability of progression of oral dysplasia …

The Effect Of Pigmentation On Thermoplastic And Thermoset Elastomeric Power Chain, William Taylor

Electronic Thesis and Dissertation Repository

Aim: The purpose of the study was to determine the effect of pigmentation on force levels and their degradation over time in orthodontic power chain of different chain types and manufactures.

Materials & Methods: Groups consisted of closed power chain from American Orthodontic (AO) thermoplastic (TP) in 5 colors, AO thermoset (TS) in 2 colors, Ormco TP in 4 colors, Ormco TS in 2 colors, and Rocky Mountain Orthodontics (RMO) TS in 5 colors (18 groups total, 10 chain samples in each group). Testing was performed over a period of 6 weeks at intervals of initial (T0), 1 hour (T1), …

Discovery Of Novel Mechanisms Regulating Cancer Extravasation In The Chorioallantoic Membrane Model, Yohan Kim

Electronic Thesis and Dissertation Repository

Cancer metastasis is a multistep process that begins with the invasion of tumour cells into the stroma and migration towards the blood vessels. Tumour cells that have entered the bloodstream must then survive and leave by a process known as extravasation. Finally, extravasated cells proliferate and establish the secondary site in the metastatic cascade. Although extravasation encompasses key events during cancer cell invasion to aid in the development of effective treatments, an in vivo model that rapidly, reproducibly and economically recapitulates cancer cell extravasation is needed. Therefore, the objectives of my research were to 1) establish and validate an in …

High Frequency Oscillations Are Phase-Amplitude Coupled In Stress Induced Seizures Following Traumatic Brain Injury, Paul Jung

Electronic Thesis and Dissertation Repository

Traumatic Brain Injury (TBI) often leads to the development of epilepsy, especially with the occurrence of stressful events. Stressors increase the levels of corticotropin-releasing factor (CRF) in the amygdala, which can be damaged by the secondary effects of TBI. It is hypothesized that the activity of CRF receptor type 1 (CRFR₁) in the amygdala is altered post-TBI and supports the generation of epileptiform waves, namely high-frequency oscillations (HFOs). Sprague-Dawley rats were given a moderate TBI and in vivo recordings of the amygdala were taken during the administration of an acute tail pinch stressor. The stressor increased broadband activity …

Piezo1: Proteins For Mechanotransduction And Integration Of Endothelial Shear Stress & Intravascular Pressure, Juan Garcia Robledo M.D.

Electronic Thesis and Dissertation Repository

Piezo proteins are transmembrane ion channels, specialized in detecting mechanosensitive stimuli and transduce mechanical forces into biochemical signals. Piezo proteins research has helped understand physiological mechanisms, but the integrative role that Piezo1 plays in the regulation of the microvasculature has remained unstudied. Our main objective was to characterize ex vivo microvascular responses to the blockade of Piezo1 mechanotransduction in male (n=29) and female (n=24) Sprague-Dawley (SD) rats. Gracilis arterioles (GA) and middle cerebral arterioles (MCA) were harvested for ex-vivo vessel preparations. After vessel viability confirmation, every vessel was submitted to myogenic and flow challenges under control conditions and after Grammostola …

Comorbid Metabolic Syndrome And Prodromal Alzheimer's Disease In A Rat Model, Nadezda Ivanova

Electronic Thesis and Dissertation Repository

Metabolic syndrome (MetS), the development of which is associated with high-caloric Western diet intake, represents a risk factor for mild cognitive impairment (MCI) and Alzheimer’s disease (AD) and appears to contribute to AD progression when MetS and AD are comorbid. The interaction between AD and MetS might be through white matter inflammation, since white matter abnormalities and inflammation are important early events in the etiopathogenesis of both diseases. In these investigations, the effect of a high-caloric diet (HCD), to induce metabolic disturbances, on white matter neuroinflammation and cognitive function was investigated in a transgenic (TG) rat model of prodromal AD …

Effect Of Histatin- And Statherin-Derived Engineered Salivary Peptides On Streptococcus Mutans Adhesion And On Enamel Demineralization Provoked By Cariogenic Biofilms, Lina Maria Marin

Electronic Thesis and Dissertation Repository

Dental biofilm is formed onto dental surfaces covered by a layer of specific salivary proteins and peptides named acquired enamel pellicle (AEP). It was previously demonstrated that the statherin- and histatin-derived engineered salivary peptides DR9-DR9 and DR9-RR14 were able to reduce enamel demineralization and displayed antimicrobial activity against Streptococcus mutans, respectively. However, these studies were carried under experimental conditions that did not mimic caries development induced by biofilm and sucrose exposure, the most cariogenic dietary sugar. In this thesis we assessed the effect of the engineered salivary peptides on 1) the adherence of S. mutans to hydroxyapatite (HAp), and …

Exploring Current Topics And Trends In Anatomy Education: A Scoping Review, Alex Wolf

Electronic Thesis and Dissertation Repository

Within the field of health professional education, one finds that anatomy often presents students with a great deal of difficulty. The literature in this area is piecemeal and there is limited work available examining the whole of this topic. A scoping review was conducted to determine how students are taught anatomy across multiple disciplines (medicine, dentistry, rehabilitation sciences, and undergraduate education) and to assess for any notable differences between these populations. The results found that scholarship on anatomy instruction varies based on educational context, and medical students are the most frequently targeted student population. It also found that the use …

Quantifying The Outcomes Of A Virtual Reality (Vr)-Based Gamified Neck Rehabilitation, Shahan Salim

Electronic Thesis and Dissertation Repository

Neck pain is a major global public health concern and adds a significant financial burden to both the healthcare system as well as people suffering from it. Additionally, it presents measurement and evaluation challenges for clinicians as well as adherence challenges and treatment barriers for the patients. We have developed a virtual reality (VR)-based video game that can be used to capture outcomes that may aid in the assessment and treatment of neck pain. We investigated: (i) performance metrics of overall accuracy, accuracy based on movement difficulty, duration, and total envelope of movement; (ii) stability across sessions; (iii) accuracy across …

Functional Magnetic Resonance Spectroscopy In First-Episode Schizophrenia: Measuring Glutamate And Glutathione Dynamics At 7-Tesla, Peter Jeon

Electronic Thesis and Dissertation Repository

Schizophrenia is a neuropsychiatric illness without known etiology or cure. Current efforts for symptom treatment still seem to leave a large portion of affected individuals without proper symptom management, with those experiencing symptom relief still having to wrestle with potential side-effects from medication trials. There has been growing evidence suggesting that glutamate and glutathione abnormalities hold major roles in development and manifestation of schizophrenia symptoms.

Magnetic resonance spectroscopy (MRS) provides a non-invasive means to observe in-vivo brain chemistry, including glutamate and glutathione. By adding a functional component to an MRS paradigm (fMRS), such as the color-word Stroop task, it is …

The Role Of The Tau N-Terminal Phosphatase-Activating Domain And Phosphorylation At Thr175 In The Formation Of Tau Cytoplasmic Inclusions, Matthew A. Hintermayer

Electronic Thesis and Dissertation Repository

Cytoplasmic inclusions and fibrils of the microtubule-associated protein tau (tau protein) are a key neuropathological hallmark in tauopathies, including Alzheimer’s disease, chronic traumatic encephalopathy, and amyotrophic lateral sclerosis with cognitive impairment. Previous research has demonstrated that the phosphorylation of tau protein at Thr¹⁷⁵ is sufficient for the initiation of fibril formation both in vitro and in vivo. Here we use mutated tau protein constructs to demonstrate that phosphorylation at Thr¹⁷⁵ results in the aberrant exposure of an N-terminal phosphatase-activating domain (PAD). The tau PAD interacts with protein phosphatase 1 (PP1) leading to the activation of glycogen synthase …

Maternal Nicotine Exposure Induces Congenital Heart Defects In The Offspring Of Mice, Elizabeth Greco

Electronic Thesis and Dissertation Repository

Congenital heart defects are the most prevalent birth defect, and maternal cigarette smoking is a known risk factor. Nicotine replacement therapies are recommended to pregnant women who smoke to aid in smoking cessation, as this alternative is thought to be much safer compared to cigarette smoking. However, these products contain nicotine, and the safety of nicotine on the developing heart is not well known. In this thesis, a mouse model was used to test the hypothesis that maternal nicotine exposure (MNE) during pregnancy leads to congenital heart defects and coronary artery defects in the offspring of mice. MNE resulted in …

Health Policy And Social Change: Women’S Advocacy Groups And Narrative Mobilization, Jill Moffatt

Electronic Thesis and Dissertation Repository

The goal of this study is to systematically investigate the mobilization of co-created (storyteller and story-gatherer) narratives for policy and social change. A case study format investigated the mobilization of narratives by a women’s health organization in London, Ontario. Semi-structured interviews resulted in transcripts from key actors. These transcripts were thematically coded and analyzed. All interview participants emphasized that from their perspective the organization did influence health policy or social change through their narrative use. Specific policy change examples were provided by participants, and social change was subjectively recognized as realized through the creation of awareness and affirmed through audience …

Towards On-Line Plan Adaptation Of Unified Intensity-Modulated Arc Therapy Using A Fast-Direct Aperture Optimization Algorithm, Michael Macfarlane

Electronic Thesis and Dissertation Repository

External beam radiotherapy (EBRT) plays a vital role in the treatment of cancer, with close to half of all cancer patients receiving EBRT at some point over their course of treatment. Although EBRT is a well-established form of treatment, there are a number of ways in which EBRT could still be improved in terms of quality and efficiency for treatment planning and radiation dose delivery. This thesis reports a series of improvements made to EBRT.

First, we developed and evaluated a new treatment planning technique called unified intensity-modulated arc therapy (UIMAT) which combines the optimization and delivery of rotational volumetric …

Haptics-Enabled, Gpu Augmented Surgical Simulation Platform For Glenoid Reaming, Vlad Popa

Electronic Thesis and Dissertation Repository

Surgical simulators are technological platforms that provide virtual substitutes to the current cadaver-based medical training models. The advantages of exposure to these devices have been thoroughly studied, with enhanced surgical proficiency being one of the assets gained after extensive use. While simulators have already penetrated numerous medical domains, the field of orthopedics remains stagnant despite a demand for the ability to practice uncommon surgeries, such as total shoulder arthroplasty (TSA). Here we extrapolate the algorithms of an inhouse software engine revolving around glenoid reaming, a critical step of TSA. The project’s purpose is to provide efficient techniques for future simulators, …

Potential Role Of Extracellular Atp Released By Bacteria In Bladder Infection And Contractility, Behnam Abbasian

Electronic Thesis and Dissertation Repository

Urgency urinary incontinence (UUI), the result of conditions such as overactive bladder (OAB), could potentially be influenced by both commensal and urinary tract infection-associated bacteria. The sensing of bladder filling involves interplay between various parts of the nervous system eventually resulting in contraction of the detrusor muscle during micturition. Here we model host responses to various urogenital bacteria, firstly by using urothelial bladder cell lines and then with myofibroblast contraction assays. To measure responses, we examined calcium influx, gene expression and alpha smooth muscle actin deposition assays. We found that organisms such as Escherichia coli IA2 and Gardnerella vaginalis ATCC …