Now showing items 1-20 of 665

    • Novel Bioactive Low-Shrinkage-Stress Composite with Antibacterial and Remineralization Properties

      ALHUSSEIN, ABDULLAH; Xu, Huakun H. (2023)
      Methacrylate-based resin composites are frequently employed in dentistry for their aesthetic qualities, durability, and adhesive properties. Nevertheless, these restorations generally exhibit a lifespan of 5 to 10 years, with recurrent caries and tooth fractures being primary failure factors. Marginal integrity and the absence of bioactivity at the tooth-restoration junction contribute to recurrent caries development. Consequently, this dissertation endeavors to introduce a novel bioactive low-shrinkage-stress nanocomposite, featuring dimethylaminododecyl methacrylate (DMADDM) as an antibacterial agent, as well as remineralization nanoparticles of calcium fluoride (nCaF2) and nanoparticles of amorphous calcium phosphate (NACP), with the potential of increase the longevity of dental restoration and protect tooth structure. All novel formulations of low-shrinkage-stress composite were subjected to a series of mechanical, antibacterial, cytocompatibility, and ion release assessments. First, we investigated the optimum concentration of DMADDM that can be incorporated with a low-shrinkage-stress composite without compromising mechanical properties. We found that incorporation of up to 5% DMADDM into a low-shrinkage stress composite efficiently inhibited Streptococcus mutans (S. mutans) biofilm commonly associated with secondary caries. This potent antibacterial effect is achieved while maintaining excellent mechanical properties and minimizing polymerization shrinkage stress, potentially improving the long-term success of dental restorations. Next, we investigated the antibacterial and cytocompatibility of the incorporation of 3% DMADDM with 20% nCaF2 or 20% NCAP into a low-shrinkage-stress nanocomposite. We found that incorporating DMADDM with either nCaF2 or NACP into a low-shrinkage-stress nanocomposite provides a potent antibacterial effect against S. mutans biofilm while maintaining excellent mechanical properties. In addition, the novel formulations demonstrated excellent biocompatibility against human gingival fibroblasts and dental pulp stem cells. Lastly, we investigated the ions release and antibacterial properties against a salivary biofilm for our innovative formulations. The innovative mixture of DMADDM, NACP, and nCaF2 demonstrated strong antibiofilm effects on salivary biofilm, while concomitantly releasing a significant amount of remineralizing ions. This nanocomposite is a promising dental material with antibiofilm and remineralization capacities, with the potential to reduce polymerization-related microleakage and recurrent caries.
    • The Alma Mater 1974

      Baltimore College of Dental Surgery, Dental School of University of Maryland. Alumni Association. (1974-04)
    • The Alma Mater 1973

      Baltimore College of Dental Surgery, Dental School of University of Maryland. Alumni Association. (1973-04)
    • The Alma Mater 1961

      Baltimore College of Dental Surgery, Dental School of University of Maryland. Alumni Association. (1961-06)
    • The Alma Mater 1959

      Baltimore College of Dental Surgery, Dental School of University of Maryland. Alumni Association. (1959)
    • Effects of Environmental Enrichment on Visceral Sensitivity and Brain Connectivity in a Mouse Model of Chronic Overlapping Pain Conditions

      MIchael, Keaser; Hanson, Shelby; Scott, Alison June; Traub, Richard J.; Da Silva, Joyce T. (2023-11-11)
    • Metformin and other metabolic inhibitors attenuate neuropathic pain and tumor growth in mice with paraneoplastic syndrome and CIPN

      Kuppusamy, Panjamurthy; Haque, Mamunui; Melemedijian, Ohannes (2023-11-15)
      Chemotherapy-induced peripheral neuropathy (CIPN) and paraneoplastic neurological syndrome are two conditions that can cause significant pain and discomfort in cancer patients. CIPN is a common side effect of certain chemotherapeutics and can result in numbness, tingling, and pain. Paraneoplastic neurological syndrome, on the other hand, is a rare disorder that occurs when cancer-fighting antibodies attack parts of the nervous system. Both neuropathies can persist which can adversely affect the quality of life and the rehabilitation of cancer patients. Unfortunately, therapies that can alleviate tumor or chemotherapy-induced neuropathic pain that do not interfere with tumor growth do not currently exist. The main goal of this study was to identify a therapeutic strategy that can achieve both anti-tumor and analgesic effects. The chemotherapeutic, bortezomib, has been shown to induce aerobic glycolysis in sensory neurons which lead to bortezomib-induce neuropathic pain. Aerobic glycolysis is also a hallmark of cancer cells, suggesting a common metabolic vulnerability. Paraneoplastic neuropathies are commonly associated with lung cancers. Hence, we used Lewis Lung Carcinoma cells (LLC1) to develop a mouse model of paraneoplastic neuropathy. We hypothesized that blocking metabolic pathways could alleviate CIPN and paraneoplastic neuropathic pain without compromising on tumor control. To test our hypothesis, we demonstrated that mice implanted with LLC1 developed significant allodynia. Treatment with bortezomib attenuated tumor growth but exacerbated the neuropathic pain. However, co-treatment with metformin, which blocks bortezomib- induced aerobic glycolysis in sensory neurons and prevents CIPN, attenuated both tumor growth and neuropathic pain. Similarly, inhibition of lactate dehydrogenase and pyruvate dehydrogenase kinase with oxamate and dichloroacetate respectively, also reduced tumor growth and pain. These results suggest that targeting metabolic pathways is a promising strategy to improve oncologic outcomes and alleviate neuropathic pain in cancer patients.
    • MDental 2023

      University of Maryland, Baltimore. School of Dentistry, 2023
    • The quality of information on oral hygiene instructions for orthodontic patients in TikTok videos

      Dorfmann, Sabrina; Schneider, Monica, D.D.S., M.S. (2023)
      Objective: The study aimed to assess the reliability, content, quality, and overall usefulness of orthodontic oral hygiene instructions in TikTok videos. Methods: The final videos were evaluated for content, reliability, quality, and usefulness by using a content domain checklist, DISCERN questionnaire, and Global Quality Scale (GQS). Descriptive video characteristics were also recorded. Results: Dental professionals uploaded 70.00% of the TikTok videos, with orthodontists responsible for 39%. The videos had average scores of 2.19 for DISCERN, 3.96 for content, 2.14 for GQS, and 6.10 for usefulness. Video length was significantly associated with content scores (r = 0.3553, P = 0.0003), usefulness (r=0.3553, P = 0.0003), and quality (GQS) (r=0.2620, P=0.0085). Conclusion: Most TikTok videos on orthodontic oral hygiene were uploaded by dental professionals. Reliability, content, and quality of the videos were all poor. Videos were considered slightly useful. Longer videos were significantly correlated with higher content, higher quality, and increased usefulness.
    • Addressing Barriers to Dental Care Access for Undocumented Pregnant Moms

      Young, Mariela; Harasta, Qian; Dedgeba, Hikam (2023-06-09)
    • Perception of lip attractiveness: a survey of orthodontists, general dentists, and laypersons

      McCormack, Katie; Copello, Flavio (2023)
      We aim to investigate the proposed standards of ideal lip proportions and compare those standards to what different people view as most attractive. A 16-question survey was distributed via Qualtrics to orthodontists, general dentists, and laypersons asking demographics as well as opinion-based questions regarding a series of facial photographs. Photographs were digitally altered using Adobe Photoshop to produce different dimensions of the lips from both profile and frontal views. Participants were asked to rate the perceived attractiveness of the lips shown. Regardless of occupation, individuals preferred the appearance of slightly protrusive or thicker lips. Retrusive and thin lip varieties had the lowest median attractiveness scores. Average values for lip projection and thickness were not found to be mutually agreed upon across occupation types (p<0.05) and average lip thickness was not mutually agreed upon between age groups of orthodontists (p=0.004). Based on the results of this study, care should be taken not to produce retrusive or thin lips during orthodontic treatment. Acceptance of a slightly thick or protrusive lip profile may be a more esthetic or well-accepted patient outcome.
    • Three-Dimensional Assessment of Virtual Clear Aligner Attachment Removal: A Prospective Clinical Study

      Dock, Jeremy; Bosio, Jose A. (2023)
      Virtual attachment removal (VAR) is a process used in digital dentistry to prefabricate retainers by removing attachments from a digital scan before the removal of clear aligner attachments. This study aims to evaluate the accuracy of VAR in the maxillary arch. 110 teeth were analyzed from a sample of 54 maxillary scans from 25 subjects. Models with attachments were virtually debonded using Meshmixer® and superimposed over the control group in MeshLab. Vector Analysis Module was used to calculate 3D distances on the buccal surfaces between the superimposed models. The VAR protocol showed no statistical differences in the root mean square between different tooth segments with an overall tendency for inadequate attachment removal. No difference between the groups were found when regarding the number of attachments was used as a main factor. The VAR technique is precise enough for the fabrication of retainers from printed dental models in a clinical setting.
    • Effect of Polydopamine-RGD Peptide Coating on the Adhesion of Cultured Fibroblasts on Polymethylmethacrylate Provisional Custom Abutment Materials

      Mui, Philip; Saito, Hanae (2023)
      Cellular attachment properties of the temporary and prosthetic abutment is one of the important factors for creating optimal peri-implant soft tissue around the implant. Surface modifications appear to play an important role in promoting early healing of the soft tissue around the dental implant, affecting primarily the epithelium, fibroblast, and osteoblast cell behavior. Another strategy to better manage peri-implant and abutment soft tissue integration is to coat the surface with bioactive agents to enhance biocompatibility. Among the most commonly utilized are proteins and peptides. The proposed in-vitro study will provide better insights of surface characteristics for implant-abutment interface by application of the peptide RGD for optimized attachment of peri-implant soft tissue cells. The hypothesis is that application of polydopamine and the peptide RGD on the implant-abutment surface can improve fibroblast early attachment, migration and proliferation, thereby advancing early wound healing and establishing peri-implant soft tissue attachment.
    • The Etiology of Peri-implantitis: Microbiological Profile Within and Around Dental Implants and the Associated Human Immune Response

      Kensara, Anmar; Masri, Radi, 1975- (2023)
      Objectives: To characterize the microbiome composition within and around dental implants of peri-implantitis subjects and within and around healthy implants using 16S rRNA gene sequencing, and to profile salivary inflammatory mediators associated with peri-implantitis compared to healthy controls from the same subjects. Methods: A total of 24 subjects (peri-implantitis n=14, healthy n=10) were enrolled in the study. From the 24 subjects, 24 endosseous implants from affected (peri-implantitis) and 14 healthy controls were included in this cross-sectional study. Samples for microbiological analysis were obtained from the internal surfaces of dental implants and peri-implant sulcus using sterile paper points. DNA was extracted and 16S rRNA gene was amplified using universal primers targeting the V3-V4 regions. Amplicons were sequenced using Illumina MiSeq platform. Alpha and beta diversity, core microbiome, and taxa differential abundance were assessed. Saliva was collected from the same subjects for immunology-based assays. Salivary inflammatory mediators in peri-implantitis and healthy implant subjects were profiled using antibody arrays. Results: A significant increase in microbial diversity was observed in the internal implant surface of healthy implants compared with the internal surfaces of peri-implantitis (Shannon P= 0.02), and no significant differences in microbial diversity between healthy implants sulci and peri-implantitis pockets (Shannon P= 0.82). Bacterial community structure was significantly different within implant in both healthy and peri-implantitis groups (P= 0.012) but not significantly different around implants in both healthy and peri-implantitis (P= 0.18). Enterococci is the predominant bacteria within peri-implantitis (LD >2.0, P< 0.05). Abundant species in peri-implantitis were C. leadbetteri, T. maltophilum, Peptostreptococcus, Neisseria, P. gingivalis, and P. endodontali, L. lactis and F. alocis (P < 0.05). Gram-positive bacteria such as S. salivaris, P. melaninogenica, L. wadei, and Actinomyces spp were more abundant in the peri-implant healthy sulcus. Around 48% of detected bacteria were cultivable in general media. In addition, out of 105 analytes examined in saliva, we found that 29 mediators were upregulated in subjects with peri-implantitis (P < 0.001). Conclusions: Our results indicate that microbial colonization of the internal implant surface may act as a major contributor to the etiology of peri-implant disease. Multiple inflammatory mediators were significantly elevated in the saliva of peri-implantitis patients compared to healthy implant patients.
    • Effect of Contact Type on Caries Experience in Primary Dentition

      Jaafar, Ameena; Dhar, Vineet VD (2023)
      Purpose: The aim is to evaluate effect of contact type and other caries risk factors (diet, plaque, and fluoride) on caries experience in primary dentation. Secondly, to assess prevalence of OXIS contacts among 3-10 years old children enrolled in the study. Methods: Clinical examination was completed on healthy children 3 to 10 years of age. Contact type of primary molars was recorded based on OXIS classification. Information on other caries risk factors were collected (plaque, fluoride, and diet habits). The outcomes assessed included clinical caries (presence/absence), decayed, missing, and filled primary teeth (dmft), decayed teeth (dt), and decayed surfaces (ds). Results: A total of 277 contacts were examined in 107 children ( 51 females and 56 males). Moderate plaque was found to be associated with dmft and dt for contacts S, I, and X. High diet frequency was associated with high dmft and dt scores for contacts S, I, and X. Contact type I showed significant association with dmft compared to other contacts in multivariable analysis. Conclusion: Both high diet frequency and moderate plaque index were linked to higher caries experience in children with contact types S,I, and X. Contact type I found to be associated with higher dmft scores compared to other contacts (X and S).
    • Comparison of Shear-bond Strength of Orthodontic Brackets on Enamel with use of Pro Seal with Assure Plus

      Greene, David; Sanchez, Dina (2023)
      Title of Thesis: Comparison of Shear-bond Strength of Orthodontic Brackets on Enamel with use of Pro Seal with Assure Plus David Greene, Master of Biomedical Sciences, 2023 Thesis directed by: Dr. Dina Sanchez, Director of Predoctoral Orthodontics, Clinical Assistant Professor, Department of Orthodontics and Pediatric Dentistry We aim to investigate the shear bond strength of orthodontic brackets bonded with Assure Plus alone and in combination with Pro Seal, following the manufacturer's recommended bonding protocol. Forty-two (42) extracted premolar human teeth were randomly assigned to two bonding groups, the control group (Assure Plus) and the test group (Assure Plus and Pro Seal). After bonding, the teeth were stored at 37°C for 24 hours. Next, the shear bond strength test was completed. The results of the Mann- Whitney test showed there was not a statistical difference of shear bond strength between the two groups for the variables, Peak Load and Shear Bond Strength. The use of Pro Seal with Assure Plus as a preventive measure for white spot lesions during orthodontic treatment does not negatively impact the shear bond strength of orthodontic brackets during treatment.
    • 2023 USA Brain Bee Championship

      Manuella, Yassa; Myslinski, Norbert (2023-06-26)
    • The Interconnection Between Periodontitis and Inflammatory Bowel Disease

      Tanwar, Himanshi; Gnanasekaran, JebaMercy; Allison, Devon; Das, Amitabh; Yesupatham, Sathish; Dilshad, Yasir; Kear, Bernice; Chung, Man-Kyo; Rasko, David A.; Ernst, Robert K.; et al. (2023-05-12)
    • Three-Dimensional Assessment of Virtual Clear Aligner Attachment Removal: A Prospective Clinical Study

      Dock, Jeremy; Copello, F.; Shirmohammadi, Iman; Bosio, Jose A. (2023-04-22)