• The Effect of Processing Techniques for rhBMP-2 Coated Titanium Implants on Alveolar Augmentation and Osseointegration in the Canine Supraalveolar Peri-Implant Defect Model

      Decker, John; Department of Oral Biology (9/5/2014)
      A current paradigm-shift in implant dentistry places restorative factors associated with esthetics and function in front of implant site selection based on bone quantity and quality. Marginal bone loss after implant placement, resorption of the edentulous alveolar ridge, bone defects from periodontal disease, and ridge aberrations due to trauma all challenge implant treatment driven by esthetics and function. Clinicians compensate for bone loss using bone augmentation procedures including bone grafts, bone materials, biologic mediators, barrier devices, or combinations thereof. The search for treatment modalities to address implant placement into compromised sites has lead to the development of a variety of products designed to replace or induce bone formation. Some believe an ideal material could be coated onto implants, to promote osseointegration, induce local bone formation, while not requiring adjunctive biomaterials, or procedures including placement of allogeneic and xenogeneic biomaterials, or autograft bone.
    • Evaluation of a Novel Compression Resistant Matrix for Recombinant Human Bone Morphogenetic Protein-2 (RHBMO-2) for Onlay Graft Indications

      Lu, Sheldon; Department of Oral Biology (6/4/2014)
      The discovery and subsequent characterization of endogenous signaling peptides known as bone morphogenetic proteins (BMPs) capable of inducing de novo bone formation in postfetal life represents a critical advancement in the understanding of tissue morphogenesis and has become an incentive to develop additional growth factor based tissue engineering strategies (Wozney & Seeherman 2004). Because BMPs act locally, a suitable carrier system must be used to ensure effective presentation of an adequate dose to a target site (Mont et al. 2004). A number of candidate biomaterials have thus been tested as potential carrier technologies (Huang et al. 2008). Currently, recombinant human BMP-2 (rhBMP-2) coupled with an absorbable collagen sponge (ACS) manufactured from bovine Achilles tendon Type 1 collagen is the only FDA approved device for orthopedic and craniofacial indications. Although the rhBMP-2/ACS construct has demonstrated clinical efficacy for indications including spine fusion, long bone fracture healing, sinus and alveolar augmentation, the ACS’s inability to resist tissue compression limits its use for onlay indications (Wikesjö et al. 2007).
    • EFFECT OF MATRIX-BOUND BISPHOSPHONATES ON MONOCYTE DIFFERENTIATION AND OSTEOCLAST FUNCTION

      Abraham, Pheba; Abraham, Pheba; Department of Oral Biology (5/1/2017)
      This study was to explore the effect of local, matrix-bound bisphosphonates to monocytedifferentiation and osteoclast function in vitro. Experiments were designed using osteoassay plates. Cell-viability, differentiation, resorption pits and gene expression were analyzed to see the effect of matrix-bound BPs on monocyte differentiation and osteoclast function. EDTA was used as a chelating agent to remove the bound BPs. There was a dose dependent response in the differentiation and resorption pits. With chelation, there was increase in differentiation, resorption pits and increase in the calcium and PYD in the supernatant. Thus, matrix-bound Bisphosphonatesare biologically active and they inhibit monocyte differentiation and osteoclast function. Thereby removal of this matrix-bound drug can rescue osteoclast differentiation and function.
    • Inherent Gene Expression and Protein Profile Differences Between Alveolar and Basal Bone

      Alotaibi, Fawwaz; Alotaibi, Fawwaz; Department of Oral Biology (5/1/2015)
      The mandible is composed to two bone types: alveolar and basal. Previous studies on the mandible have shown that the alveolar bone resorbs more than the basal bone after tooth extraction or as a result of tooth movement. Reasons for why the resorption rates are different is not well understood. This research begins exploring the differences of the alveolar and basal bone by using comparison characteristics such as bone mineral density (BMD), gene expression, protein profiles, and number of osteocytes. The research investigates these characteristics by using Real time RCR to study the differences in gene expression and protein profiles of the alveolar and basal bone. Micro-CT was used in comparing density and bone architecture characteristics of the alveolar and basal bone. Immunohistochemistry was used to better understand how osteocytes are different between the two bone types in hopes of later being able to understand the differences in resorption rates. The real time PCR showed that four genes are expressed significantly higher in basal bone than alveolar bone: SOST, E-11, DMP-1, MEPE. Three of which are associated with mature osteocytes indicating that basal bone has more mature osteocyte phenotypes. Micro-CT data indicated that the basal bone is denser and less porous than alveolar bone. There was no significant difference in immunohistochemistry and further quantitative testing is needed to draw and significant correlation.
    • Marker Co-Expression Analysis of Initial Cellular Events in the Critical-Size Rat Calvarial Defect Model and the Effect of Bone Morphogenetic Protein-2 (rhBMP-2)

      Capetillo, Joseph F.; Department of Oral Biology (4/15/2016)
      Craniofacial defects can result from congenital malformations, trauma, tumor resection,periodontal disease, post-extraction ridge remodeling, and peri-implantitis. Regenerationof bone is critical to achieving functional and esthetic outcomes in the rehabilitation ofsuch defects. Traditional strategies for osseous regeneration include a multiple ofsurgical techniques utilizing autologous bone, cadaver-sourced allogeneic or xenogeneicbone, synthetic bone biomaterials, barrier membranes, or combinations thereof(Wikesjö, Qahash 2009). The need to enhance the predictability of regeneration inespecially large defects that cannot heal adequately without intervention (critical-sizedefects) has led to recent development of protein- and cell-based technologies.[Introduction, first paragraph]
    • The role of Toll-like receptor (TLR) 2 in the systemic immune response profile of mice induced to develop squamous cell carcinoma of the upper aerodigestive tract

      El-Shafey, Sally; El-Shafey, Sally; Department of Oral Biology (4/1/2017)
      Background Head and necksquamous cell carcinomais associated with immunosuppression, a state in which the progression of cancer is associated with disturbances in the immune system functions. Emerging studies suggest a fundamental role for the innate immune system, particularly Toll-like receptor 2 (TLR2), in this process.QuestionsIn this study, we investigated the potential roles of TLR2 on systemic immune profile in a mouse model of headand necksquamous cell carcinoma.MethodsTwo different protocols of a mouse model of 4-nitroquinoline 1-oxide and ethanol-induced carcinogenesis to induce head and neck squamous cell carcinoma were used. To evaluate the systemic immune profiles, total RNA wasisolated from the spleens of four groups of animals, including carcinogen-treated and control untreated wild-type and toll-like receptor 2-deficient animals. Quantitative real-time PCR was performed forgenesrepresentative of house-keeping genes, type 1 and type 2 immune responses, regulatory T and B cells, and adenosine receptors.Results and ConclusionIn the standard protocol of 4-nitroquinoline 1-oxide and ethanol-induced carcinogenesis, there was asignificant upregulation of adenosine receptor A2a in the spleens of wild type iiimice treatedwith4-nitroquinoline 1-oxide and ethanolrelative to wild type untreatedanimals. In the standard protocol of carcinogenesis, there was a significant upregulation of CD39 in the spleens of TLR2-koanimalstreated with 4-nitroquinoline 1-oxide and ethanol relative to untreated TLR2-ko mice. These results suggest that carcinogenesis in the upper aerodigestive tract is associated with alterations in the systemic immune profile reflected in the spleen. However, the specific impact on the immune profiles appears to be affected by the presence or absence of TLR2.
    • Changes in the RANK/RANKL/OPG Signaling System as a Mechanism of Zoledronate-Induced Osteonecrosis of the Jaw

      Lane, Jonathan; Department of Oral Biology (3/22/2016)
      Bisphosphonates (BPs) are widely used for the treatment of osteoporosis, hypercalcemia of malignancy, skeletal-related events associated with bone metastases, and for managing lytic lesions of multiple myeloma. A serious risk associated with the use of BPs is the development of Bisphosphonate Related Osteonecrosis of the Jaw (BRONJ), a painful and inflamed area of exposed bone in the oral cavity that fails to heal after 6-8 weeks. The cause of BRONJ is unknown, but it is believed to be due primarily to a longterm suppression of bone remodeling, caused by BP’s potent inhibition of osteoclastic activity. At the cellular level, it is generally accepted that bisphosphonates are taken in by osteoclasts at sites of relatively greater bone remodeling, owing to the strong affinity of bisphosphonates for the mineralized matrix and the increased activity of osteoclasts at active sites of resorption. The accumulation of intracellular bisphosphonates ultimately leads to osteoclast dysfunction or apoptosis through the formation of nonhydrolyzable ATP-analogues, or due to inhibition of the mevalonate pathway responsible for synthesis of sterols and lipids necessary for proper cellular membrane structure. However, the refined details of the pathophysiology of BRONJ remain elusive. The RANK/RANKL/OPG system is a well-known signaling pathway for the recruitment and differentiation of osteoclasts. RANK is a surface-bound receptor on osteoclasts, and requires binding of its ligand, RANKL, for cell activation and ultimately resorption of bone. On the other hand, OPG is a soluble decoy receptor for RANKL. Therefore, osteoclastic activity is effectively regulated by the ratio of RANKL to OPG. For years, it has been generally accepted that osteoblasts are the primary source of both RANKL and OPG. However, it is now recognized that the master orchestrator of bone activity, the osteocyte, contributes to the pathway. Furthermore, it has been shown that in localized tissue damage or hypoxia, such as in a dental extraction, immediately adjacent surviving nonapoptotic osteocytes upregulate RANKL and downregulate OPG. It is unknown to what extent BPs may alter the normal osteocyte response to injury and hypoxia or, ultimately, the dynamics of the RANK/RANKL/OPG system. Furthermore, the extent to which this could contribute to the development of BRONJ is unexplored.There is a paucity of studies concerning how the fundamental system responsible for bone remodeling, RANK/RANKL/OPG, is effected by BPs. It may be that changes in this system, especially in signals derived from the osteocyte, contribute to the pathophysiology of BRONJ.
    • The Application of Low-Cost, Close-Range Photogrammetry in Dentistry

      Patel, Mohit; Mettenburg, D.; Biological Sciences, Restorative Sciences (Augusta University Libraries, 2020-05-05)
      This item presents the abstract for a poster presentation at the 21st Annual Phi Kappa Phi Student Research and Fine Arts Conference.
    • Efficacy of Epigallocatechin-3-gallate-palmitate as a Virucidal Compound Against Norovirus

      Widjaja, Nicole; Department of Oral Biology and Diagnostic Sciences (Augusta University, 2020-05)
      Norovirus is a highly infectious, non-enveloped virus found to be the leading cause of global gastroenteritis outbreaks. Every year within the United States, this virus is responsible for an average of 19-21 million cases of acute gastroenteritis, approximately 570-800 deaths, and has been the cause of 1.7 to 1.9 million outpatient visits. On a global scale, healthcare costs and lost productivity are estimated to $60 billion due to illnesses and outbreaks caused by the burden of norovirus. Unfortunately, current measures to prevent the transmission of norovirus remain insufficient as the Center for Disease Control and Prevention (CDC) can only recommend hand washing with soap and water as the best preventative measure. The only other hand hygiene method available is alcohol-based hand sanitizers, but the CDC states that they are not effective in inactivating norovirus particles and warns that it should not be considered a substitute to hand washing. Recently, epigallocatecin-3-gallate (EGCG) a major component extracted from the leaves of Camellia sinensis, also commonly known as tea plant, has shown potential to be the next viable candidate as an antiviral solution. Lipid derivatives of EGCG, most notably EGCGpalmitate, has shown to express potent antiviral properties and has showed to play a crucial role in the fight against other non-enveloped viruses such as poliovirus and adenovirus. In this study, we determined the efficacy of EGCG-palmitate in novel formulations against human norovirus surrogates by utilizing the EU international standards for hand hygiene in vitro studies against norovirus. Evidence is provided determining the virucidal activity of alcohol-based ProtecTeaV formulations containing EGCG-palmitate as well as the potential for EGCG-palmitate as a persistent residual virucidal activity against norovirus surrogates, feline calicivirus (FCV) and murine norovirus-1 (MNV-1). By creating an effective, environmentally friendly, non-toxic and long lasting solution composed of EGCG-palmitate, the results of this innovative approach would expand the options available to reduce the transmission of norovirus essentially bridging the gap for a new preventative hand hygiene and ultimately impacting the spread of norovirus on a worldwide scale.
    • Biocompatibility and mechanical/physical properties of 3D printed, milled, and conventionally processed denture base materials

      Ulmer, Mallory; Biomedical Sciences (Augusta University, 2019-12)
      According to the American College of Prosthodontists, over 36 million people in the USA are edentulous with a 2:1 predilection for geriatric patients1. Each year, an estimated 15% of edentulous Americans will seek denture treatment1. Conventional dentures require multiple visits and lab processing time. 3D printing technology offers the potential to reduce the number of appointments and speed up the time until patient rehabilitation. However, the newly FDA-certified 3D printer denture resins, featuring secretive and proprietary formulae, lack studies concerning their biocompatibility/safety and mechanical strength. This study aims to investigate the biocompatibility and physical properties of one such 3D printer resin, NextDent® Base (Vertex, Soesterberg, The Netherlands), and compare it to pre-existing conventional polymethyl methacrylate (PMMA) denture base (Lucitone 199, Dentsply Sirona, York, Pennsylvania) and milled PMMA denture base (IvoBase CAD®, Ivoclar Vivadent AG, Schaan, Liechtenstein). The cytotoxicity was examined using of 12 discs: conventional PMMA, milled PMMA, as-printed 3D printer resin, post-cured 3D printer resin, and Teflon controls. An MTT assay using human periodontal ligament (900L) cells was employed, and specimens were aged for 1, 3, 7, 10, and 14 days. After day 7, there were no statistically significant differences among the groups, excluding the Teflon control, which showed significantly less cell viability on day 14. Bars of conventional PMMA, milled PMMA, as-printed 3D printer resin, and post-cured 3D printer resin were subjected to a 3-point bend test to examine flexural strength and moduli differences. The mean flexural strength was 63.8 ± 3.06, 82.6 ± 1.9, 5.1 ± 0.4, and 22.1 ± 6.4 MPa, respectively, while the flexural moduli were 1757.3 ± 109.5, 2226.7 ± 76.3, 110.3 ± 20.3, and 537.0 ± 210.6 MPa, respectively. The flexural strength and modulus were significantly different among all groups. Weibull analyses for conventional PMMA, milled PMMA, as-printed 3D printer resin, and post-cured 3D printer resin revealed a Weibull modulus of 23.5, 42.8, 16.6, and 3.7, respectively, and a characteristic strength of 65.2, 83.5, 5.3, and 24.5 MPa, respectively. The characteristic strength was significantly different among all groups as well. The Weibull modulus was significantly different between all groups, except for conventional vs. as-printed, which were not significantly different. In summary, milled PMMA featured significantly greater mechanical properties. Both 3D printed groups proved to be very weak, with the as-printed group being the weakest of all. The differences between the as-printed and post-cured groups highlight the importance of properly post-curing the resin. While the biocompatibility results showed promise, the mechanical testing results were disappointing. Unfortunately, the findings suggest that 3D-printed denture base resin is not yet ready for clinical use.
    • SYNERGISTIC EFFECTS OF THE COMBINATION OF ERLOTINIB & EXO2 ON HEAD AND NECK CANCER

      Thakkar, Parth; Department of Biological Sciences; Department of Oral Biology; Teng, Yong; Augusta University (2019-02-13)
      More than 90% of head and neck cancer is head and neck squamous cell carcinoma1 (HNSCC). Currently, the treatment involves modern surgery, conventional chemotherapy, and radiation. However, targeting, the epidermal growth factor receptor (EGFR) has been shown to prove advantageous for patient survival. EGFR activation leads to cell cycle progression. Blocking the EGFR by an antibody results in the inhibition of the receptor, therefore inhibition of cell proliferation. This makes EGFR a prime target for anticancer therapy, specifically with tyrosine kinase inhibitors being looked at as a possible form of inhibition. The goal of this project was to hopefully use small molecule inhibitor EXO2 and an EGFR specific tyrosine kinase inhibitor, Erlotinib, in a synergistic manner to fight against HNSCC. This study was done using cell cultures, MTT assay�s and western blot techniques, with cell cultures being done using the H6 cell line. The results from this study were found to be a preliminary success and will pave the way for future experiments in this area.
    • SERUM-C TERMINAL CROSSLINKING TELOPEPTIDE (CTX) AS A PREDICTIVE BIOMARKER OF BISPHOSPHONATE-RELATED OSTEONECROSIS OF JAW (BRONJ): SYSTEMATIC REVIEW AND META-ANALYSIS

      Sun, Christina; Awad, Mohamed E; Jernigan, Joshua; College of Science and Mathematics; Department of Oral Biology; Dental College of Georgia; Elsalanty, Mohammed; Augusta University (2019-02-13)
      The aim of this systematic review was to evaluate the validity of using preoperative serum C-terminal crosslinking telopeptide (CTX) levels as predictive factor of increased risk of developing medication-related osteonecrosis of the jaw (MRONJ) in patients on bisphosphonate (BP) therapy who undergo invasive dental procedures. A search was conducted through PubMed, MEDLINE, and Web of Science, following PRISMA guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. Meta-analysis was conducted on the risk ratio. The methodological index for nonrandomized studies (MINORS) and Quality Appraisal of Reliability Studies (QAREL) checklist were used to assess quality. Eighteen clinical trials, involving 2301 patients were included. Most patients received Alendronate or Risedronate for an average of 62.14 months. The average serum CTX level in BP-treated patients before surgery was 217.67 pg/ml. Meta-analysis demonstrated that the cutoff in CTX level (150 pg/ml) was not predictive of BRONJ risk. The sensitivity of CTX value <150 pg/ml was 34.26% and the specificity was 77.08%. The use of CTX to diagnose BRONJ risk following dental procedures in bisphosphonate-treated patients is not justified. Further studies are needed to develop other reliable biomarkers.
    • Direct Composite restorations Using a Clear PVS Matrix to restore Worn Anterior Dentition to Create an Ideal Occlusal Plane

      Fowlkes, Colton; Romero, M; Urbanawiz, D; Department of Restorative Sciences (Augusta University, 2019)
      This clicnical case documents the use of a clear PVS matrix technique to restore the incisal edges of worn mandibular anterior teeth using flowable composite to provide a 20 degree template for eventual complete maxillary denture and mandibular removable partial denture frabrication.
    • Murine Dendritic Cell Interactions with Minor-fimbriae P. gingivalis

      Yuan, J; Auersvald, c; Elashiry, M; Meghil, M; Elashiry, M; Finger Stadler, A; Arce, R.M.; Department of Periodontics (Augusta University, 2019)
      The objective was to determine DC maturity phenotype of murine bone marrow-derived DCs in response to wild/type (PgWT) and minor-fimbriated DPG3.
    • SALIVA WETTING OF DIFFERENT TYPES OF DENTURE BASE RESINS: PILOT STUDY

      Baxter, John; Brenes, C; Rueggeberg, FA; Departments of General Dentistry; Department of Restorative Sciences (Augusta University, 2019)
      Direct, tissue-borne, full denture restoration of edentulous arches has become a well accepted restoration modality for millions of people. In this methodology, the tissue-bearing surface of a polymeric material replacing the form and structure of lost alveolar bond and overlying mucosa rests directly on the residual ridge tissue. Retention of the denture is attained through capillary adhesion forces acting to wet (cover) both the oral mucosa and the polymeric denture bases that rests upon it. Good wetting by saliva is thus one of the many critical features affecting adhesion of the denture base to the oral mucosa. Measurement of the ability of a fluid to wet a surface is performed using the shape of a fluid droplet on that surface. If the fluid wets that surface, then the droplet will spread out. If the fluid does not wet that surface, it will bead up. Quantitative measurement of fluid flow on a surface is performed using measurement of the “contact angle.” In this method, a controlled volume is dispensed onto a surface, and while viewing the interaction of that fluid in silhouette, the angle formed at the tangent of that drop and the flat surface is determined. The lower the contact angle, the more a fluid wets a surface, and the higher its value, the less wetting is that fluid on a specific surface.
    • Aesthetic improvement of a smile using minimal intervention procedures. A case report

      Cowan, Marcus; Babb, C; Romero, M; Pruett, M; Coleman, J; Department of Restorative Sciences (Augusta University, 2019)
      Tooth discoloration, particularly affecting the maxillary anterior teeth, is often an esthetic concern for dental patients.1 The most common cause of intrinsic tooth discoloration is dental fluorosis (DF),1 which is enamel hypomineralization due to long-term ingestion of high levels of fluoride during tooth mineralization.2 DF results in white opaque areas or discolorations ranging from yellow to dark brown, with porosities on the enamel surface.3 A widely-used scale for classifying the severity of DF is the Tooth Surface Index of Fluorosis (TSIF), developed by Horowitz, by which the examiner determines the extent of affected enamel by estimating the amount of DF as a fraction of the total visible enamel surface.4 Microabrasion, introduced by Croll and Cavanaugh in 1986,5 is a technique used to correct surface enamel irregularities and remove intrinsic enamel stains through the application of hydrochloric acid combined with pumice in a paste.6 When performed correctly and conservatively, the amount of enamel loss from microabrasion is clincally insignificant.7 The success of microabrasion depends upon the extent and severity of the discoloration, and occasionally a slightly yellowish appearance will result from the yellow dentin shade showing through the translucent enamel.8 The final appearance can be improved by dental bleaching, with long-lasting results.7 The following article is a clinical report of the use of microabrasion combined with nightguard bleaching with 10% carbamide peroxide to improve the appearance of teeth affected by fluorosis.