Now showing items 1-20 of 640

    • Novel Bio-interactive Fixed Dental Restoration Cement with Potent Antibacterial and Remineralization Properties

      AlSahafi, Rashed A.; Weir, Michael D.; Xu, Huakun H. (2022)
      Resin-based cement is increasingly used in clinical practice due to its excellent mechanical and physical properties. The cementation and accurate placement of fixed dental restorations with an ideal marginal adaptation to the tooth structure remains a challenging laboratory and clinical task. The marginal gap of fixed dental restoration increases the opportunity for microleakage, plaque accumulation, and tooth demineralization by increasing the potential for food buildup around the margin and exposing the tooth-cement interface to the oral cavity. Thus, there is an increased need to develop a new generation of bio-interactive dental cement with antibacterial, long-term remineralization abilities, and excellent mechanical properties. Therefore, this dissertation aims to invent new bio-interactive resin-based cement containing dimethylaminohexadecyl methacrylate (DMAHDM), nanoparticles of amorphous calcium phosphate (NACP), and nanoparticles of calcium fluoride (nCaF2), which could be a promising approach to increase the chances of success of fixed dental restoration and strengthen tooth structures. All new cement formulations were subjected to a series of mechanical, antibacterial, and ion release assessments. In the first manuscript, we found that the new NACP+DMAHDM cement has excellent potential for fixed restoration cementation, as it efficiently inhibited S. mutans biofilm commonly associated with secondary caries and maintained an excellent mechanical property with high levels of Ca and P ions released. In the second manuscript, we found that incorporating DMAHDM and NACP into resin-based cement provides strong antibacterial action against saliva microcosm biofilm and presents a high level of Ca and P ion recharge abilities. In the third manuscript, we found that the new cement with both NACP and nCaF2 demonstrated the advantages of both types of bio-interactive fillers as it could release a higher level of ions than the resin cement with only nCAF2 and exhibits a better rechargeability compared to the resin cement with only NACP. Lastly, in the fourth manuscript, we found that the novel antibacterial low-shrinkage-stress resin-based cement provided strong antibacterial action and maintained excellent mechanical properties with reduced polymerization shrinkage stress, which could improve the long-term success of the fixed dental restoration.
    • Caries Experience Based on A Simulated Epidemiological Screening and Routine Examination with Radiographs

      Kuchari, Abrar; Dhar, Vineet (2022)
      Purpose: To assess and compare caries experience based on an epidemiological “screening” examination and a routine examination with radiographs. Methods: 128 patients ages 5 to 10 years were included. An initial examination was done by a pediatric dentist in conditions simulating an epidemiological screening assessment. A second evaluation was done by eight postgraduate pediatric dental resident who conducted a routine clinical exam of the patient in the dental chair including radiographs. Results: By the epidemiological screening, the prevalence of untreated dental caries (Y/N) in primary and/or permanent teeth was 50% and the caries experience was 77%. After the routine examination with radiographs, the prevalence of untreated dental caries was 74.22% and caries experience was 90%. The severity of untreated dental caries was 2.0 and 3.9, and the severity of caries experience was 3.2 and 5.6 by the simulated epidemiological screening and routine examination with radiographs, respectively.
    • MDental 2022

      University of Maryland, Baltimore. School of Dentistry, 2022
    • Assessing Postpartum Oral Health Literacy and Needs as Medicaid Dental Coverage Expands

      Christensen, Paige; Kim, Hee Yeon; Yates, Kristin; Bress, Lisa (2022-07)
    • Alumni: Baltimore College of Dental Surgery, 1913-1916

      Baltimore College of Dental Surgery (1916)
      Photograph album of the Baltimore College of Dental Surgery Alumni and Faculty. The album dates from 1913-1916. Album is available in the Internet Archive, see link.
    • Alumni: Baltimore College of Dental Surgery, 1901-1912

      Baltimore College of Dental Surgery (1912)
      Photograph album of the Baltimore College of Dental Surgery Alumni and Faculty. The album dates from 1901-1912. Album is available in the Internet Archive, see link.
    • Alumni: Baltimore College of Dental Surgery, 1892-1900

      Baltimore College of Dental Surgery (1900)
      Photograph Album of the Baltimore College of Dental Surgery Alumni dated 1892-1900. The 1892 and 1893 class graduates have been identified. Album is available through the Internet Archive, see link.
    • Alumni: Baltimore College of Dental Surgery, 1883-1891

      Baltimore College of Dental Surgery (1891)
      Photograph album of the Baltimore College of Dental Surgery Alumni and Faculty. The album dates from 1883 to 1891. Album is available in the Internet Archive, see link.
    • Generational Perspectives of Orthodontists in the U.S. and Canada– A Survey Study

      Hussain, Syed Rassal; Bosio, Jose A. (2022)
      Objective: To identify differences between generations of orthodontists in the U.S. and Canada and to evaluate the perspective of each generation on widely debated topics in orthodontics. Materials and Methods: A 22-item IRB approved survey was distributed to orthodontists in the U.S. and Canada. Participants were asked questions about the use of technology, future of clear aligner therapy (CAT), orthodontic education, student debt, marketing, and corporate orthodontics among other topics. Results: Significant increase in female orthodontists over generations and a decrease in orthodontic educators was found (P<0.001). Among generations, differences were found in regard to their amount of student debt, use of specific diagnostic tools, marketing preferences, and their opinion on the future of CAT. Conclusions: Clear distinctions exist between different generations of orthodontists. Issues such as increasing student debt load and a decrease in orthodontic educators over generations should be addressed to preserve the future of the orthodontic profession.
    • The role of Angiopoietin-like 4 in head and neck squamous cell carcinoma progression and dissemination

      Hefni, Eman; Montaner, Silvia (2022)
      Dysregulation of cellular signaling is instrumental in the promotion of tumor cell metabolism, proliferation, tissue invasion and metastasis. Molecular-based therapies for neoplastic diseases are designed to modulate or interact with cell surface receptors, intracellular cascades, or microenvironment components related to the extracellular matrix, tumor vasculature and immune response. To design these therapies, an improved understanding of the molecular underpinnings leading to tumor growth is essential. The overall aim of our investigation is identification of the molecular mechanisms associated with the induction of tumor cell migration and proliferation induced by Angiopoietin-like 4 (ANGPTL4), a pro-tumorigenic and pro-angiogenic factor, in head and neck cancer squamous cell carcinoma (HNSCC). HNSCC accounts for around 54,000 new cases and 11,000 deaths per year in the United States. Unfortunately, the clinical management of this tumor remains challenging. Our studies, divided into two research aims, use in vitro cell-based models together with signal transduction and cell and molecular biology methods. Our results demonstrate that: 1) ANGPTL4 is upregulated in human-derived dysplastic oral keratinocytes (DOKs) and HNSCC cell lines, but not in normal oral keratinocytes (NOKs), suggesting an early and sustained role for ANGPTL4 in disease progression. ANGPTL4 is a molecular marker in biopsies from patients with mild-moderate or moderate oral epithelial dysplasia, primary HNSCC and metastatic HNSCC. ANGPTL4 is necessary and sufficient to promote cell migration in DOKs and HNSCCs lines. Binding of ANGPTL4 to neuropilin-1 (NRP1) leads to paxillin (PXN) phosphorylation and cell migration in an ABL1-dependent manner, exposing the ANGPTL4/NRP1/ABL1/PXN cascade as a vulnerable target for HNSCC treatment. 2) Epidermal Growth Factor (EGF)- and Hypoxia-inducible Factor-1 (HIF-1)-mediated pathways cooperate in the upregulation of ANGPTL4 in normal and dysplastic oral keratinocytes and HNSCC cells. Besides EGF, the EGF ligand amphiregulin leads to an increase in ANGPTL4 and is upregulated in HNSCC lesions. ANGPTL4 activates the HNSCC molecular markers p38 MAPK, AKT and mTOR in NOKs; these kinases may act as potential intracellular regulators of the autocrine signals and paracrine secretions that ANGPTL4 activates to promote HNSCC tumorigenesis. Collectively, our findings suggest that ANGPTL4 and its associated signaling molecules are potential therapeutic targets in HNSCC clinical management.
    • Global Temporary Anchorage Device (TAD) Usage: A Survey of Orthodontists

      Ashton, Kelsea; Bosio, Jose A.; 0000-0002-8045-3370 (2022)
      Objective: We aim to determine how often TADs are used worldwide and establish guidelines for implementing TADs in everyday practice. Methods: A 19 question survey was sent to orthodontists around the world asking opinion based, case-specific, and placement technique questions regarding TADs. The country of practice and length of time practicing orthodontics were the independent variables. Results: Most orthodontists use TADs rarely/sporadically. There were significant findings for how TADs are being used, sizes, and placement techniques amongst different continents. There was a significant difference in how many TADs orthodontists placed in residency according to how long they have been practicing, but it did not greatly affect frequency of use, mechanics, or placement technique. Conclusion: The frequency of TAD use is similar worldwide and amongst different age groups. Although significant data was found in this study, there is such variability in regard to TADs that clear guidelines were not established.
    • Optimal Antero-Posterior Position of the Maxillary Central Incisors and its Relationship to the Forehead in Adult African American Males

      Endres, Elise Tigani; Sanchez, Dina (2022)
      Objective: To determine an optimal antero-posterior (AP) position of the maxillary central incisors (CI) and its relationship to the forehead in African American males. Methods: 95 smiling profile photographs were taken, evaluated by orthodontists and laypersons, and categorized in Group B, R or F. The CI position and forehead inclination (FI) were measured relative to glabella vertical (GV). Statistical analysis evaluated the relationship between CI position and FI, differences between groups, and differences between orthodontists and laypersons. Results: Optimal CI position was -2.1mm behind GV. There were no significant differences between orthodontists and laypersons. All group comparisons were significantly different, except Group B v Group R. The optimal CI position relative to GV and FI were not significantly correlated. Conclusions: The AP position of the CI relative to the forehead in African American males can be evaluated to determine the optimal AP position of the CI and optimal esthetics.
    • The Perspectives of Middle Atlantic Society Orthodontists on COVID-19

      Vumback, Matthew; Schneider, Monica, D.D.S, M.S. (2022)
      Purpose: This study aims to survey Middle Atlantic Society Orthodontists on how COVID-19 has impacted and altered their practices and outlook on the profession. Methods: This cross-sectional study was designed using Qualtrics XM and consisted of 20 questions focusing on the licensed orthodontists in the MASO regions. Results: Responders had split feelings regarding the length of time out of practice due to regulations. Nearly 48% felt that it was too long, while about 49% felt that it was appropriate. During this time, over 32% have offered more aligner therapy but roughly 51% have seen a reduction in patients. Regardless, over 61% do not believe retirement plans have been affected. Conclusion: A meaningful difference in perspectives exists amongst MASO orthodontists regarding COVID-19 regulations and infection control. Treatment philosophy appears to be shifting towards clear aligner therapy and tele-dentistry. Despite the disruption to the profession, most orthodontists feel hopeful for the future.
    • A Novel Magnetic Nanoparticle Containing Adhesive to Enhance Microtensile Bond Strength of Composite Resin to Dentin: An in vivo Study.

      Bulloch, Brandon; Masri, Radi, 1975- (2022)
      Purpose: An in vivo study to compare microtensile bond strength and resin tag density of a novel adhesive that relies on magnetic force. Materials and Methods: Twenty-five teeth were obtained from subjects. In the experimental group, teeth were restored with a novel nanoparticle adhesive and magnetic force (n=16). In the control group (n=9), no nanoparticle or magnetic force was used. Teeth were extracted and cut into beams. Microtensile bond strength and resin tag density were measured. A two tailed student t test was used to compare groups. P<0.05 was considered significant. Results: There was a significant increase of microtensile bond strength of the experimental group compared to controls (P= 0.025). The SEM images showed resin tag density was increased by a magnitude of two with the experimental group. Conclusion: Magnetic force improves the microtensile bond strength and resin tag density of resin adhesive when used in vivo.
    • The effect of silver diamine fluoride on the surface roughness of dental ceramics

      Chandy, Tintu Sara; Masri, Radi, 1975- (2022)
      Purpose: This study compared the effect of silver diamine fluoride, acidulated phosphate fluoride and distilled water on the surface roughness of dental ceramics. Materials and Methods: Rectangles of zirconia, lithium disilicate and feldspathic porcelain were treated with 38% SDF, 1.23% APF and distilled water. The surface roughness of each rectangle was measured using a profilometer before and after treatment with the solutions. Multiple comparison of the means among the ceramics and testing solutions was done using 2-Way ANOVA followed by Tukey’s test. P<0.05 was considered significant. Results: APF created the greatest surface roughness compared to SDF and water. Zirconia was unaffected by all solutions. SDF increased the roughness of lithium disilicate and felspathic porcelain, however the results were not statistically significant compared to the control group. Conclusions: With many topical fluoride preparations available, dentists should be aware of their effect on different ceramic systems to prevent surface roughening of restorations.
    • Comparing the Accuracy of Occlusal Vertical Dimension Transfer in Cad-Cam Dentures

      Satin, Sara Reanne; Masri, Radi, 1975-; 0000-0001-8470-6948 (2022)
      This laboratory-based study investigated the accuracy of transferring the VDO of the maxillary/mandibular relationship when designing and fabricating digital dentures by evaluating two commonly used workflows: duplicate dentures (DD) and occlusion rims (OR). 15 STLs were obtained for each workflow. Three measurements in deviation (mm) were obtained, then 3D-deviation values were averaged for each workflow at each location. A two-way ANOVA was used for the statistical analysis to evaluate differences between the methods and location of measurement. The average deviation for OR was higher than DD at all locations of measurement. There was a statistically significant difference between the DD and OR workflows [F=46.00, p<0.0001]. There was no statistically significant difference in deviation between the points of measurement [F=0.15, p<0.86] or between the location and method [F=0.02, p<0.98]. The DD workflow exhibited less deviation in transfer of VDO than the OR workflow. The location of the measurements had no significance.
    • A non-classical mechanism of β-lactam resistance in Methicillin Resistant Staphylococcus aureus (MRSA) and its effect on virulence

      Satishkumar, Nidhi; Lai, Li-Yin; Poon, Raymond; Mukkayyan, Nagaraja; Chatterjee, Som S. (2022-06)
    • Synergistic action of GdpP and PBP4 mediates high-level, broad-spectrum, non-classical β-lactam Resistance in Staphylococcus aureus

      Lai, Li-Yin; Satishkumar, Nidhi; Poon, Raymond; Mukkayyan, Nagaraja; Chatterjee, Som S. (2022-06)