Digital Commons Network^™

Identification Of Virulence Determinants For Streptococcus Sanguinis Infective Endocarditis, Lauren Turner

Theses and Dissertations

Streptococcus sanguinis is the second most common causative agent of bacterial infective endocarditis (IE). Risk of S. sanguinis IE is dependent on pre-disposing damage to the heart valve endothelium, which results in deposition of clotting factors for formation of a sterile thrombus (referred to as vegetation). Despite medical advances, high mortality and morbidity rates persist. Molecular characterization of S. sanguinis virulence determinants may enable development of prevention methods. In a previous screen for S. sanguinis virulence determinants by signature-tagged mutagenesis (STM) an attenuated mutant was identified with a transposon insertion in the nrdD gene, encoding an anaerobic ribonucleotide reductase. Evaluation …

Modeling Pure Vasogenic Edema In The Rat Brain, Charles Nottingham

Theses and Dissertations

Targeted drug delivery to the brain is difficult to achieve using conventional techniques, largely due to the blood-brain barrier’s (BBB) impediment to drug diffusion into the brain parenchyma. In response, development of convection-enhanced delivery (CED) offers the ability to circumvent the BBB and target specific areas of the brain. Predictability of infusate movement in pathological brain states during CED will maximize the effectiveness of this treatment, and therefore modeling of infusate movement must be characterized. Previous work from our lab effectively modeled CED in rats using the middle carotid artery occlusion model of cytotoxic edema. However, previous models examined for …

Physiological And Molecular Characterization Of Genetic Competence In Streptococcus Sanguinis, Alejandro Rodriguez

Theses and Dissertations

The ability of bacteria to assimilate free DNA from the environment is known as competence. Though many studies have focused on competence regulation in Streptococcus pneumoniae and Streptococcus gordonii, Streptococcus sanguinis has yet to be examined. Physiological characterization of competence in S. sanguinis strain SK36 and its comC mutant, JFP41, led to the genome-wide transcriptional analysis of cells induced to competence via addition of competence-stimulating peptide (CSP). A total of 128 genes were induced at least 2-fold, 74 of which were classified as either “early” or “late” based on their induction patterns. Expression patterns were verified using qRT-PCR. This study …

Contamination Of Dental Waterlines: Efficacy Of Seven Waterline Treatments And Three In-Office Bacteria Test Kits, Adam Davis

Theses and Dissertations

This study compared seven dental unit water line (DUWL) treatments and three in-office bacteria test kits. Sodium hypochlorite (NaOCl) 1:10 in tap water weekly; 3 drops of NaOCl in 1 liter of water; Dentapure® DP 40; ICX™ tablet; Sterilex® Ultra powder; Lines™; and Selective Micro® Dental-Clean. Traditional culture technique was compared to HPC Dental Sampler; Aquasafe™ Dental Unit Water Line Test Kit; and Bacteria in Water Test Kit. Eight dental units in the Virginia Commonwealth University Graduate Endodontic Clinic were randomly assigned treatment regimens. Samples were taken weekly initially and after flushing for 1 minute. In conclusion NaOCl hypochlorite 1:10 …

Communication Skills Instruction Utilizing Interdisciplinary Peer Teachers: Program Development And Student Perceptions, Sharon K. Lanning, Sonya L. Ranson, Rita M. Willett

Periodontics Publications

Lack of curricular time, faculty time, and funding are potential limitations for communication skills training in dentistry. Interdisciplinary collaboration amongst health care faculties could address these limitations. This article describes the development, implementation, and student perceptions of a communication skills program in dentistry. The program has four components: Knowledge, Observation, Simulation, and Experience (KOSE) and spans over the second and third years of dental school. KOSE allows students to obtain knowledge of and observe effective communication skills and practice these skills in the simulated and nonsimulated environment. A key feature of KOSE is the utilization of fourth-year medical and dental …

Quantifiying The Depth Of Oral Sedation Using Bispectral Index Monitoring, John Flowers

Theses and Dissertations

Purpose: To determine whether Bispectral Index Monitoring is an effective tool for quantifying sedation depth after the administration of oral drug regimens in children.Methods: This retrospective study reviewed the charts of 75 children who received oral conscious sedation for dental treatment. Data collected from the chart included; 1) BIS values at 5 minute intervals and at five critical events: pre-operative, local anesthesia delivery, rubber dam placement (if utilized), during operative treatment, and postoperatively, 2) behavior ratings at the five critical events and an overall behavior assessment, 3) treatment data, and 4) demographic data. Results: The mean BIS value for orally …

The Use Of Implants Vs. Endodontics: Practitioner Attitudes In 2007, Gardiner Mckay Packer

Theses and Dissertations

The purpose of this study was to determine what factors influence dentists when deciding whether to place an implant or perform endodontic retreatment. Null hypothesis: Dentists today are no more likely to place an implant than to perform endodontic retreatment. A twelve-item questionnaire was mailed to 525 general dentists and specialists who are members of the Richmond Dental Society. Response rate was 61.9%. The questionnaire included items on demographics, practice profile and cases of failing endodontic therapy which participants were asked to consider and chose between endodontic retreatment or implant placement. The relationship between the treatment choices and the characteristics …

Accuracy Of Ct Colonography For Detection Of Large Adenomas And Cancers, Daniel C. Johnson, Mei-Hsiu Chen, Alicia Y. Toledano, Jay P. Heiken, Abraham Dachman, Mark D. Kuo, Christine O. Menias, Betina Siewert, Jugesh I. Cheema, Richard G. Obregon, Jeff L. Fidler, Peter Zimmerman, Karen M. Horton, Kevin Coakley, Revathy B. Iyer, Amy K. Hara, Robert A. Halvorsen Jr, Giovanna Casola, Judy Yee, Benjamin A. Herman, Lawrence J. Burgart, Paul J. Limburg

Radiology Publications

Background

Computed tomographic (CT) colonography is a noninvasive option in screening for colorectal cancer. However, its accuracy as a screening tool in asymptomatic adults has not been well defined.

Methods

We recruited 2600 asymptomatic study participants, 50 years of age or older, at 15 study centers. CT colonographic images were acquired with the use of standard bowel preparation, stool and fluid tagging, mechanical insufflation, and multidetector-row CT scanners (with 16 or more rows). Radiologists trained in CT colonography reported all lesions measuring 5 mm or more in diameter. Optical colonoscopy and histologic review were performed according to established clinical protocols …

Virginia Dental Journal (Vol. 85, No. 1, 2008)

Virginia Dental Journal

No abstract provided.

Treatment Outcomes And Retention In Medicaid And Non-Medicaid Orthodontic Patients, Ashkan Ghaffari

Theses and Dissertations

Medicaid orthodontic patients have been shown to miss more appointments and break more appliances than self-pay patients, indicating a greater tendency toward non-compliance. Lack of compliance during the post-treatment phase can be detrimental to retention. The purpose of this study was to determine whether there is a difference in PAR score changes between Medicaid and non-Medicaid patients during and after orthodontic treatment. PAR scores were determined using study models of 43 Medicaid and 39 non-Medicaid patients before and at the end of active treatment, and 24 Medicaid and 42 non-Medicaid patients at the end of treatment and at an average …

Density Of Gutta Percha By Weight In Straight Root Canals And Curved Root Canals After Single Cone, Cold Lateral, And Warm Vertical Condensation, Gerald Clay Sparrow

Theses and Dissertations

The purpose of this study was to compare the density of gutta percha following three different obturation techniques using two split-tooth models. One split-tooth model was constructed with a straight rooted maxillary incisor and the other with the curved palatal root of a maxillary molar. Each tooth was obturated using single cone, cold lateral, and warm vertical obturation techniques without sealer. Each obturation technique was performed 20 times for each of the root systems. The weights of the gutta percha were recorded for each root type and obturation technique by subtracting the post-fill weight from the pre-fill weight of the …

Virginia Emergency Department Physician Knowledge Of The Emergent Treatment Of Avulsed Teeth, Joy Leatrice Barnes Phelps

Theses and Dissertations

Purpose: The purpose of this study was to determine the knowledge and treatment protocols for physicians in Virginia emergency departments in regards to the emergent treatment of avulsed teeth.Methods: Using a cross sectional survey design, an 8-item questionnaire regarding the treatment of avulsed teeth was emailed to 75 emergency department chairpersons in Virginia. After 30 days, a reminder paper copy of the questionnaire was mailed and an email reminder with the on-line link was sent. After 60 days the study was closed. Comparisons were made using chi-square analysis based on percentages to test for significance. Results: The response rate was …

Virginia Dental Journal (Vol. 85, No. 2, 2008)

Virginia Dental Journal

No abstract provided.

Alternative Orthodontic Bonding Protocol Using Self Etching Primer, Rush-Baker Gaines Caldwell

Theses and Dissertations

The purpose of the current study was to develop a bonding method that can achieve clinically acceptable bond strength values while leaving a minimum amount of adhesive on the tooth surface during the debonding process. One hundred teeth were randomly assigned into groups. Five different enamel surface preparation protocols were tested (N = 20, each): Conventional acid etch, standard SEP, SEP applied with a light brush stroke (altered SEP 1), SEP applied directly to the composite of pre-coated bracket (altered SEP 2), and Primer Only groups. Brackets were debonded using an Instron universal testing machine (Instron, Canton, MA) in shear …

Comparison Of Emergence Behavior In Pediatric Dental Patients Undergoing General Anesthesia With Sevoflurane Versus Desflurane, Carla Lalande

Theses and Dissertations

Purpose: To determine which maintenance gas (sevoflurane versus desflurane) resulted in a faster emergence from general anesthesia and investigate the patient's emergence agitation. Methods: One group was maintained during general anesthesia with sevoflurane and the other with desflurane. Upon emergence the patient's behavior was evaluated.Results: The average emergence time for desflurane was 9.8; while the average for sevoflurane was 13.98 minutes. Patients who received premedication had an emergence time of 15.43 minutes, while patients who received no premedication emerged after 8.34 minutes.Zofran® was a significant predictor of purposeful actions. Patients were more aware of their surroundings when they received Zofran® …

Virginia Dental Journal (Vol. 85, No. 4, 2008)

Virginia Dental Journal

No abstract provided.

A Comparison Of Five Radiographic Systems To D-Speed Film In The Detection Of Artificial Bone Lesions, David Lloyd Hadley

Theses and Dissertations

The purpose of this study was to compare three direct digital sensors (Kodak 6100, Schick CDR, and Dexis PerfectSize), a phosphor plate system (OpTime), and F-speed film to standard D-speed film in the detection of artificial bone lesions prepared in mandible bone sections. Multiple artificial bone lesions were prepared at varying depths in the cortical bone. Specimens were imaged with six different radiographic systems. Radiographs were randomly presented to nine different observers. A logistic regression analysis indicated that the ability of the different radiographic systems to detect the bone lesions was significantly different at the mean percentage of cortical bone …

The Psychosocial Influence Of Dental Esthetics In Adolescents As Judged By Peers, Scott Thomas Henson

Theses and Dissertations

The purpose of this study was to determine if dental esthetics affects the perception of adolescents regarding their peer's social aptitude in specific areas such as athletics, popularity, leadership, and academics. Ten patient photographs (4 males, 6 females) from a private orthodontic practice in Richmond, VA were selected for inclusion in this study. The frontal smiling photographs were digitally modified with insertion of either an ideal smile (straight) or a non-ideal smile (crooked) to create an image identical to the original except for an altered dental complex. Laypersons rated the straight and crooked patient photographs for athletic performance, socialization skills …

Fluoride Varnish Use Among Dentists In Virginia, Amanda Bowen Kuhn

Theses and Dissertations

Purpose: The purpose of this study was to asses fluoride varnish use by dental practitioners in Virginia. Methods: Using a cross sectional survey design, all dentists in Virginia who are members of the Virginia Dental Association (VDA) were sent an online survey about usage and knowledge of fluoride varnish. Results: The majority of the respondents were general dentists (79%) followed by pediatric dentists (12%). Fluoride varnish use increased with year of graduation from dental school. Dentists who thought fluoride varnish was more effective and less time consuming use it more than other topical fluorides. Dentists who thought their patients prefer …

Virginia Dental Journal (Vol. 85, No. 3, 2008)

Virginia Dental Journal

No abstract provided.

Esthetic Posterior Stainless Steel Crowns And Their Relative Shear Strengths, Lonny Dale Carmichael

Theses and Dissertations

Purpose: The purpose of this study was to evaluate esthetic posterior stainless steel crowns (EP-SSC) and compare their relative shear strengths.Methods: Sixty EP-SSC were compared. 15 crowns from NuSmile® Primary Crowns, Kinder Krowns, and Dental Innovators 1UP and EC Crowns were studied. The crowns were cemented to a typodont tooth then thermally cycled in water baths to simulate oral conditions. Shear strengths were evaluated by subjecting these crowns to simulated forces of occlusion.Results: The force required to cause shearing of the esthetic facings was statistically significant. With the 1UP crown being significantly weaker than the other crowns tested. Conclusion: The …

Orthodontic Bracket Bond Strength Using Self-Etching Primer With Or Without Pumice Or Acid Etch Pretreatment, Ana Paula Decastro

Theses and Dissertations

The purpose of this study was to compare the shear bond strength of orthodontic brackets to enamel in four bonding protocols: SEP without prior pumicing (None), Pre-etch and SEP without prior pumicing (Pre-etch), control: SEP with prior pumicing (Pumice), and Pre-etch and SEP with prior pumicing (Both). 80 extracted bovine incisors were randomly divided into 4 groups of 20, and brackets were bonded under the different experimental conditions. Debonding force was measured with an Instron universal testing machine. A two-way ANOVA comparing the four groups indicated that there was a significant difference in debonding force (P = 0.001). The SEP …