Digital Commons Network^™

Comparison Of Intraoral And Extraoral Scanners On The Accuracy Of Digital Model Articulation, Jason L. Porter

Theses and Dissertations

Introduction: Orthodontists increasingly rely on digital models in clinical practice. The ability of modern scanners to articulate digital models must be scientifically evaluated. Methods:Twenty five digital articulated models were produced from four digital scanners in five experimental groups. The resulting inter-arch measurements were compared to the gold standard. An acceptable range of 0.5mm more or less than the gold standard was used for evaluation. Results: iTero® and iTero® Element yielded all acceptable inter-arch measurements. The 3M™ True Definition and Ortho Insight 3D® with Regisil® bite registration produced four of six acceptable inter-arch measurements. The Ortho Insight 3D® with Coprwax ™ …

Nitrosative Stress Sensing In Porphyromonas Gingivalis: Structure And Function Of The Heme Binding Transcriptional Regulator Hcpr, Benjamin R. Belvin

Theses and Dissertations

Porphyromonas gingivalis, a Gram negative anaerobe implicated in the progression of periodontal disease, is capable of surviving and causing infection despite high levels of reactive nitrogen species found in the oral cavity due to its efficient nitrosative stress response. HcpR is an important sensor-regulator that plays a vital step in the initiation of the nitrosative stress response in many Gram negative anaerobic bacteria. We employ a combination of X-ray crystallography, SAXS, resonance Raman spectroscopy, UV-Vis spectroscopy, and molecular biology techniques to better understand this key regulator. Knockout of the hcpR gene in W83 P. gingivalis results in the inability of …

A Comparison Of Treatment Planning Modalities For The Pediatric Dental Patient, Martha M. Holland

Theses and Dissertations

Purpose: To assess the treatment modalities of pediatric dentists for restoring Class II lesions in primary molars.

Methods: A survey of eight cases was emailed to AAPD members, who were asked to choose a stainless steel crown (SSC) or composite resin. Treatment choice was associated with provider type, years in practice, behavior management, lesion detection, and patient age.

Results: Clinically detectable caries restored under general anesthesia were treated more often with a SSC. Faculty and residents chose a SSC at a greater rate. Providers with 10 or more years experience chose a SSC more often.

Conclusions: The scope of treatment …

The Prevalence, Predictive Factors, And Classification Of Intrapulpal Cracks In Maxillary Molars Requiring Endodontic Treatment, Husain Karashi

Theses and Dissertations

Diagnosis and treatment of teeth with longitudinal fractures is challenging. Cracks are usually not visible radiographically; they require a thorough evaluation to aid in diagnosis. Patients may be asymptomatic, demanding the dentist rely on clinical findings to make a diagnosis. Early diagnosis of the presence and extent of a crack is essential for the successful management of a cracked tooth. There is limited information in the literature regarding the prevalence or predictive factors of cracks extending into the pulp chamber of teeth. The purpose of this study was to determine the prevalence of intrapulpal cracks in maxillary molars and to …

Prevalence And Clinical Characteristics Of Teeth Extracted With A Diagnosis Of Cracked Tooth: A Retrospective Study, Riley B. Sturgill

Theses and Dissertations

The body of knowledge that exists regarding cracked teeth is limited. The purpose of this study was to determine the prevalence of cracks among extracted teeth. This retrospective longitudinal cohort study included patients of the Virginia Commonwealth University School of Dentistry that underwent extraction procedures over a 6 year period. The sample consisted of 20,408 patients and 40,870 teeth. Statistical analysis software was used to identify diagnoses of a crack, fracture, or split tooth prior to extraction of the tooth by analyzing the Electronic Health Record (EHR) (axiUm™, Version 6.03.03.1035, Exan Corporation, Vancouver, BC, Canada). There were 3,228 teeth …

Role Of The Pediatric Dental Provider In Human Papillomavirus (Hpv) Education, Meredith L. Dugoni

Theses and Dissertations

Purpose: This study investigates knowledge about HPV and examines if pediatric dental providers should include HPV education for guardians of patients 10-18 years.

Methods: Legal guardians of 10-18 year-old patients of the Virginia Commonwealth University Pediatric Dental Clinic were enrolled in this prospective cohort study. Participants completed a baseline survey, were provided HPV education, completed an initial follow-up survey, and then completed a 6-month follow-up survey.

Results: A total of 54 participants completed the baseline and initial follow-up surveys and 17 completed the 6-month follow-up survey. The average number of correct responses was 3.4 of 6 knowledge questions, which significantly …

Weighted Quantile Sum Regression For Analyzing Correlated Predictors Acting Through A Mediation Pathway On A Biological Outcome, Bhanu M. Evani

Theses and Dissertations

Abstract

Weighted Quantile Sum Regression for Analyzing Correlated Predictors Acting Through a Mediation Pathway on a Biological Outcome

By

Bhanu M. Evani, Ph.D.

A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University.

Virginia Commonwealth University, 2017.

Major Director: Robert A. Perera, Asst. Professor, Department of Biostatistics

This work examines mediated effects of a set of correlated predictors using the recently developed Weighted Quantile Sum (WQS) regression method. Traditionally, mediation analysis has been conducted using the multiple regression method, first proposed by Baron and Kenny (1986), which has since …

In Search Of A Function For An Uncharacterized Conserved Protein In Streptococcus Sanguinis Sk36, Ayana Scott-Elliston

Theses and Dissertations

With the number of fully sequenced bacterial genomes increasing in the past 7 years, it has been discovered that a large percentage of the putative protein coding genes have no known function. This lack of knowledge leaves scientists with an incomplete understanding of bacteria. In this study, conserved hypothetical protein mutants from Streptococcus sanguinis SK36 were screened on solid media with various environmental conditions. From these screens, the candidate protein, SSA_2372, displayed a sensitivity to acidic conditions. Its homolog in Bacillus subtilis 168, BSU00030, also displayed a sensitivity to pH conditions at its acid tolerance extremes unlike its other homolog …

A Biorelevant In Vitro Model To Characterize In Vivo Release Of Bone Morphogenetic Protein-2 (Rhbmp-2), Deblina Biswas

Theses and Dissertations

Biorelevant in vitro release/dissolution tests are designed to predict the in vivo behavior of a drug and are crucial in understanding its in vivo performance. Currently, there is no standardized compendial in vitro release testing methods or regulatory guidance’s for release/dissolution testing of implants due to their complex physiological locations.Furthermore, existing compendial methods do not capture the local release profile of ‘novel’ parenterals in physiological low fluid volume surrounding areas.

Long acting and in situ forming implants with orthobiologic proteins and peptides have increased over the past few decades due to a better understanding of genetic engineering. One of these …

Investigating The Relationship Between Emotional Intelligence And Cultural Intelligence To Attitudes Towards Team-Based Learning In Undergraduate Pre-Health Profession Students, Kevin A. Harris

Theses and Dissertations

Improving patient outcomes has long been the rationale supporting calls to reform health care delivery systems and health profession education programs (Greiner, 2002; Institutes of Medicine, 2001, 2004; O’Neil & Pew Health Professions Commission, 1998). In 2003, the Institute of Medicine shared its vision statement for health professions education, asserting that “[a]ll health professionals should be educated to deliver patient-centered care as members of an interdisciplinary team, emphasizing evidence-based practice, quality improvement approaches and informatics” (Knebel & Greiner, 2003, p. 3).

Despite the importance placed on teamwork in health sciences education, little attention has been devoted to understanding underlying factors …

Ineffable: Latency In Symbolic Languages, Sirah Yoo

Theses and Dissertations

The design process demands comprehensive knowledge of visual signs and symbols with a focus on visual literacy; it is related to visual syntax, semantics, and the pragmatics of contexts. My work is an interdisciplinary investigation into how designers integrate polysemantic signs into their design process for particular and highly individualized audiences. By analyzing the role of signs in specific contexts across the spectrum of arts, society, literature, and semiotics, a designer's understanding of the cyclical nature of interpretation and reinterpretation in complex environments creates an avenue for cultivating a new schema that provides further levels of interpretations and different access …

Amixicile Inhibits Anaerobic Bacteria Within An Oral Microbiome Derived From Patients With Chronic Periodontitis, Kane Ramsey

Theses and Dissertations

Periodontitis is a chronic inflammatory disease caused by pathogenic bacteria residing in a complex biofilm within a susceptible host. Amixicile is a non-toxic, readily bioavailable novel antimicrobial that targets strict anaerobes through inhibition of the activity of Pyruvate Ferredoxin Oxidoreductase (PFOR), a major enzyme mediating oxidative decarboxylation of pyruvate. Our study aimed to evaluate the efficacy of amixicile, when compared to metronidazole, in inhibiting the growth of bacteria present in a microbiome harvested from patients with chronic periodontitis.

Plaque samples were harvested from patients with severe chronic periodontitis and cultured under anaerobic conditions. The microbiomes were grown in the presence …

Determinants Of Hospital Administrators' Choice Of Anesthesia Practice Model, Maribeth L. Massie

Theses and Dissertations

Hospital administrators are being held accountable by patients, insurers, and other stakeholders in evaluating their overall hospital performance to reduce costs and improve efficiency. With the move to alternative payment models and value-based purchasing, hospital administrators must understand the economic viability and value that their specialty services bring to their facility.

The purpose of this study was to identify the determinants New England acute care hospital administrators’ utilize in making the choice of anesthesia practice model for their facility.

A quantitative, exploratory study of factors hospital administrators use when choosing an anesthesia practice model utilizing a non-experimental, correlational research design …

Evaluation Of Volumetric Change Of Periapical Lesions After Apicoectomy As A Measure Of Postsurgical Healing Utilizing Cone Beam Computed Tomography, Eshwar Arasu

Theses and Dissertations

The aim of this study was to evaluate whether volumetric changes in persistent periapical lesions can be detected in follow-ups six months to five years after apicoectomy using cone-beam computed tomography. Patients with a previous treatment history of apicoectomy and for whom a pre-surgical CBCT scan was taken between November 2010 and December 2015 were invited to participate in the study. A post-surgical CBCT image of the treated tooth was obtained at the recall visit. Volumetric and linear measurements of periapical lesions on initial and postoperative CBCT images were performed using DiThreshGUI software and two calibrated examiners—a board-certified endodontist and …

A Comparative Study Of Intraradicular Enterococcus Faecalis Biofilm Removal With Three Root Canal Treatment Systems: A Scanning Electron Microscopy Evaluation, Cyrous Ardalan

Theses and Dissertations

The objective of this study was to evaluate the biofilm removal efficacy of three root canal treatment systems: ProUltra® PiezoFlow™, traditional needle irrigation, and the GentleWave® system in an ex-vivo benchtop study. Twenty-four extracted maxillary and mandibular molars were selected. Teeth were all instrumented to a master apical file size #25 with 4% taper. Teeth were then randomly divided into four experimental groups and two control groups. The root canals were inoculated with a culture of Enterococcus faecalis and incubated for five weeks to form a biofilm. Each group was then treated with one of the different root canal treatment …

Silver Diamine Fluoride And Oral Health-Related Quality Of Life, Nazafarin Javdan

Theses and Dissertations

Purpose: The purpose of this study was to study the association between Silver Diamine Fluoride (SDF) and Oral Health-Related Quality of Life as assessed by “The Early Childhood Oral Health Impact Scale” questionnaire. Methods: Parents of healthy children (ASA I and II) ages 1-5 with early childhood caries with reversible pulpitis who had application of SDF filled out a questionnaire at baseline and again after one month. The questionnaire was designed to evaluate the child’s behavior, physical abilities, pain, temperament, and how well the child gets along with others. Results: Wilcoxon Signed Rank Test was used to …

Orthodontists' And Parents' Perspective Of Occlusion In Varying Anterior-Posterior Positions: A Comparative Study, David H. Lindsey

Theses and Dissertations

Objective: The purpose was to compare orthodontists’ and parents’ perception of orthodontic treatment outcomes in the anterior-posterior (AP) dimension. Assessment of treatment time and compliance were also investigated.

Material and Methods: Parallel surveys for orthodontists (n=1000) and parents (n=750) displayed occlusions from 3 mm Class III (Cl III:3) to 3 mm Class II. Participants rated occlusal relationships on a 100 mm VAS from least to most acceptable (0-100).

Results: 233 orthodontists (23%) and 243 parents (32%) responded. Orthodontists (mean=93.9, 25.9) and parents (mean=80.7, 40.9) rated Class I (Cl I) occlusion most and Cl III:3 least acceptable. No significant difference was …

A Comparison Of Moderate Oral Sedation Drug Regimens For Pediatric Dental Treatment: A Pilot Study, Ojas A. Parikh

Theses and Dissertations

Purpose: Compare moderate oral sedation of pediatric patients using Hydroxyzine and Meperidine with either Diazepam or Midazolam in management of pediatric dental patients.

Methods: Randomized, double-blind, crossover pilot study of patients 3 to 7 years of age requiring two sedation visits. Frankl and Houpt behavior scores recorded at injection time, initiation of treatment and 100% oxygen at end of treatment. Postoperative phone call surveys conducted within eight hours and within 24 hours of discharge. Wilcoxon Signed-Rank tests, Fisher’s Exact Chi-squared test and 0.10 significance level.

Results: 25 subjects completed 35 sedations. Eight participants completed both treatments and demonstrated significantly higher …

Biochemical Analysis Of Putative Single-Stranded Nucleic Acid Binding Proteins In Porphyromonas Gingivalis, Steve H. Kokorelis

Theses and Dissertations

Proteins that bind to both DNA and RNA embody the ability to perform multiple functions by a single gene product. These nucleic acid binding proteins in prokaryotes can play a vital role in many cellular processes, including replication, transcription, gene expression, recombination, and repair, to name a few. Nucleic acid binding proteins have unique functional characteristics that stem from their structural attributes that have evolved in a widely-conserved manner. In Escherichia coli (E. coli), the highly-conserved histone-like protein, HU, which predominates as a heterodimer of HUα and HUβ, has been found to bind to both dsDNA and ssDNA. …

An Evaluation Of Critical Resources In Nurse Anesthesia Educational Programs, Lois E. Stewart

Theses and Dissertations

Advanced practice nurses fill a vital need in the U.S. by increasing access to needed healthcare. Certified Registered Nurse Anesthetists (CRNAs) are one type of advanced practice nurse with a long history of safe and effective peri-anesthetic care. Nurse anesthetists have a rich tradition of providing anesthetic care for rural and underserved communities, and are a primary provider of anesthesia for active and retired military personnel. CRNAs comprise over one-half of the actively practicing U.S. anesthesia workforce currently, and are able to function in any anesthetic care model. Nurse anesthesia educational programs (NAEPs) are the single source for new graduate …

Come Fly With Me: Using Amixicile To Target Periodontal Pathogens And Elucidating The Innate Immune Response In Drosophila Melanogaster, Kathryn Sinclair

Theses and Dissertations

Periodontal diseases (PD) affect 46% of American adults over age 30. These diseases cause symptoms including bleeding and swelling of the gums, bone resorption, and tooth loss, that affect quality of life and have a high economic burden. Periodontal diseases are caused by an imbalance in the oral microbiome, from a healthy state that contains anti-inflammatory commensals like Streptococcus gordonii and mitis, to a diseased state that has pro-inflammatory anaerobic pathogens including Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Tannerella forsythia. The latter initiate disease progression in the oral cavity. However, it’s the host immune …

Development Of An Electrospun And 3d Printed Cellular Delivery Device For Dermal Wound Healing, Ryan M. Clohessy

Theses and Dissertations

The goal of this research was to develop a system of individualized medicine that could be applied to dermal wounds serving as a wound dressing and synthetic extracellular matrix while delivering stem cells to the wound bed. First, fabrication parameters for electrospinning polymer fibers were determined. This involved evaluating fiber morphology with respect to polymer selection and solution concentration. Next, construct fabrication was examined to produce an integrated void space, or cargo area, suitable to maintain stem cells. In vitro studies to ensure stem cell viability and phenotype were conducted, and results supported the notion that cells could be administered …

Comparisons Of Isogenic Trisomic And Disomic Cells From People With Mosaicism For Down Syndrome Unmask Cellular Differences Related To Trisomy 21, Kelly A. Rafferty

Theses and Dissertations

It is known that age-related changes impacting multiple organ systems occur earlier in people with Down syndrome (Ds), but the biological basis underlying this trisomy 21-associated propensity for premature aging is poorly understood. Given that the trisomic/normal cells from people with mosaic Ds (mDs) are identical with regards to environmental exposures and genes (except for chromosome 21 copy number), comparisons of these isogenic trisomic/disomic cells allow one to “unmask” the cellular consequences of trisomy 21 by removing extraneous factors. The primary aim of this study was to determine if trisomy 21 results in an increase in the acquisition of age-related …

A Systems Biology Approach For Predicting Essential Genes And Deciphering Their Dynamics Under Stress In Streptococcus Sanguinis, Fadi El-Rami

Theses and Dissertations

Infectious diseases are the top leading cause of death worldwide. Identifying essential genes, genes indispensable for survival, has been proven indispensable in defining new therapeutic targets against pathogens, major elements of the minimal set genome to be harnessed in synthetic biology, and determinants of evolutionary relationships of phylogenetically distant species. Thus, essentiality studies promise valuable revenues that can decipher much of biological complexities.

Taking advantage of the available microbial sequences and the essentiality studies conducted in various microbial models, we proposed a framework for the prediction of essential genes based on our experimentally verified knowledge of the pathways involved in …

Contribution Of A Class Ii Ribonucleotide Reductase To The Manganese Dependence Of Streptococcus Sanguinis, John L. Smith

Theses and Dissertations

Manganese-deficient Streptococcus sanguinis mutants exhibit a dramatic decrease in virulence for infective endocarditis and in aerobic growth in manganese-limited media. Loss of activity of a manganese-dependent, oxygen-dependent ribonucleotide reductase (RNR) could explain the decrease in virulence. When the genes encoding this RNR are deleted, there is no growth of the mutant in aerobic broth culture or in an animal model. Testing the contribution of the aerobic RNR to the phenotype of a manganese transporter mutant, a heterologous class II RNR from Lactobacillus leichmannii called NrdJ that requires B₁₂ rather than manganese as a cofactor was previously introduced into an …

The Role Of Human Msc Derived Exosomes In The Treatment Of Periodontal Diseases, Sonia S. Talegaonkar

Theses and Dissertations

Periodontal disease affects 47% of Americans over 30. Characterized by microbial dysbiosis and unregulated inflammation, severe periodontitis causes degradation of bone and soft tissue around teeth. Current treatments have limited regenerative outcomes and frequent reinfection by harmful bacteria. Human mesenchymal stem cells (hMSCs) have been shown to promote wound healing and tissue regeneration. Many therapeutic benefits of hMSCs are due to their secretome products, like exosomes. Our long-term goal is to develop periodontal therapies with hMSC exosomes. The objectives of this study were to determine the effect of hMSC-derived exosomes on cellular activity of hMSCs and investigate whether hMSC exosome …

Fabrication Of Flexible, Biofunctional Architectures From Silk Proteins, Ramendra K. Pal

Theses and Dissertations

Advances in the biomedical field require functional materials and processes that can lead to devices that are biocompatible, and biodegradable while maintaining high performance and mechanical conformability. In this context, a current shift in focus is towards natural polymers as not only the structural but also functional components of such devices. This poses material-specific functionalization and fabrication related questions in the design and fabrication of such systems. Silk protein biopolymers from the silkworm show tremendous promise in this regard due to intrinsic properties: mechanical performance, optical transparency, biocompatibility, biodegradability, processability, and the ability to entrap and stabilize biomolecules. The unique …

An Integrated Behavioral Model Of Healthcare Utilization Among Transgender And Gender-Nonconforming Adults, Megan Elizabeth Sutter

Theses and Dissertations

Transgender and gender-nonconforming (TGNC) individuals in the United States experience significant marginalization due to stigma enacted at the structural, interpersonal, and individual levels. As a result, this population has reported increased behavioral and physical health needs, as well as unique barriers to healthcare. Moreover, TGNC individuals have reported greater experiences of childhood abuse compared to cisgender individuals. The cumulative experiences of stigma-related stressors and adverse childhood experiences put this population at risk for the development of mental and physical health problems, increasing need for health services. However, TGNC individuals have reported being denied medical care and postponing seeking care due …

Provider Appearance: A Survey Of Guardian And Patient Preference, Joshua Westphal

Theses and Dissertations

Purpose: To understand guardian and child preferences for the appearance of their pediatric dentist. This was a cross-sectional descriptive study using survey methodology with patients and parents that attended the VCU Pediatric Dental clinic.

Methods: A total sample of 100 guardians and 97 pediatric patient participants completed the computer-based questionnaire. Four subjects were asked to pose for photographs wearing various combinations of attire (professional, casual, white coat, scrubs).

Results: Among guardians, 56% reported preferring a provider in scrubs, with white coat the second most preferred attire (39%) for their children. For pediatric patients, scrubs were still most often selected, …

Modulating The Innate Immune Response To Electrospun Scaffolds And Polymer Degradative Byproducts, Daniel Abebayehu

Theses and Dissertations

Implanted biomaterials often induce inflammation that frequently leads to the foreign body response, fibrosis, and the failure of the implant. Thus, it is important to evaluate how cells interact with materials to promote a more regenerative response. It is critical to determine how to modulate the response of tissue resident innate immune cells, as they are among the first cells to interact with implanted materials. Among tissue resident innate immune cells are mast cells, which are inflammatory sentinels that degranulate and orchestrate the fate of other cell populations, such as monocytes/macrophages and lymphocytes. Mast cells have also been reported to …