• The Role of Oral Microbiota in Bisphosphonate-Induced Osteonecrosis of the Jaw: Rat Tibial Defect Model

      Jernigan, Joshua; Awad, Mohamed E.; Elsayed, Ranya; Elsalanty, Mohammed (Augusta University, 2019)
      This study aims to develop a rat model for post-traumatic osteonecrosis at an extra-oral bone site that simulates the oral micro-environment, specifically the proximal tibia.
    • 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.

      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.

      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.
    • Soft Tissue and Bone Healing at Platform Shift Abutment in One-Stage Implants: A Radiographic, Histologic, and Histometric Study in Dogs

      Wenzel, Brent A.; Department of Oral Biology (2011-04)
      Matching-diameter and platform shift abutments were randomized to 40 dental implants placed into 5 dogs following mucoperiosteal flap elevation. 1x5 (width x height) mm peri-implant gap defects were surgically created in randomly assigned jaw quadrants. All implants were placed 2 mm subcrestally. Mucoperiosteal flaps were sutured around the abutments for primary intention healing. Radiographs were recorded immediately, 4-, and 8 weeks postsurgery when block biopsies were removed for histometric analysis. The histological examination showed the junctional epithelium was arrested coronal to the implant platform without significant differences among experimental conditions. Crestal bone height demonstrated no significant differences among groups at buccal or lingual sites. Bone-implant contact reached 0.4 mm below the platform at buccal sites. Higher variability was observed at lingual sites without differences among groups. Platform shift abutments offer negligible benefit compared to conventional abutments to maintain peri-implant crestal bone and soft tissue contours.
    • The stability of an increased vertical dimension of occlusion in growing and non-growing golden hamsters

      Berman, Scott C.; Department of Oral Biology (Augusta University, 1993-03)
    • Sustained Release Formulation for Vascular Endothelial Growth Factor

      Elzinga, Jennifer Lynn; Department of Oral Biology (2013-03)
      Necrosis of tissue due to trauma or a surgical procedure is a complication of wound healing. This necrosis, or tissue death, occurs when the vasculature is unable to perfuse involved tissue with the oxygen and nutrients necessary to maintain viability. To provide adequate access, reflecting a flap of tissue is often necessary in a variety of surgical procedures, including periodontal surgeries. The success of these procedures is limited by the development of tissue flap necrosis. The survival of these tissue flaps is dependent upon adequate perfusion by the blood vessel supply at the base of the flap, followed by the growth of new vascular channels from the recipient site. However, if angiogenesis does not promptly reach the distal extent of the flap, this portion becomes ischemic, leading to necrosis. Loss of the protective flap delays healing and increases the risk of scarring and infection. Necrosis of this distal region of a tissue flap begins as early as 24 hours following the surgical procedure and progresses rapidly until day 3 when the unaffected tissue begins to stabilize.1 A variety of pharmacological strategies to enhance tissue flap perfusion have been tested in an attempt to prevent necrosis. One such strategy is the administration of angiogenic growth factors such as vascular endothelial growth factor (VEGF). VEGF is known to stimulate the proliferation of endothelial cells from existing vasculature to create new blood vessels, thus enhancing 8 tissue survival.2-7 In addition, VEGF contributes to other aspects of wound healing, including inflammation, granulation tissue formation, reepithelialization, matrix formation, and remodeling.2 Administration of VEGF to wound healing models has shown promising results by increasing vascular formation, leading to enhanced tissue perfusion. However, its short duration of action and rapid dissipation from the target site reduces its effectiveness.8 Maintaining therapeutic concentrations of VEGF at the target site to maximize new vessel growth and reduce necrosis, either multiple applications or an extended-release delivery system is required. An ideal system would provide ease of use and delivery kinetics for sustained therapeutic dosing of VEGF to the wound environment for the duration of healing, thereby minimizing tissue necrosis. A variety of application methods and delivery systems are under investigation in the search to develop one that provides utility as well as improved clinical outcome.

      Elzinga, Jennifer Lynn; Department of Oral Biology (2/1/2013)

      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.
    • Time To Open Repair Of Mandible Fractures And Associated Complications

      James, Jeffrey; Farrell, Thomas; Faigen, Alex; Anderson, Jessica; Department of Oral and Maxillofacial Surgery (Augusta University, 2019)
      The aim of this study is to determine whether a correlation exists between the time from injury to repair of mandible fractures and the development of post operative complications.
    • Toxicity of visible light-cured denture resins

      Barron, Dara Jewell; Department of Oral Biology (1992-04)
      In this study three commercial formulations of visible light-cured (VLC) denture resins have been analyzed. The products used are those suggested for the reline, repair and fabrication of dentures to improve their fit. The biocompatibility of these resins was investigated by measuring RNA and DNA synthesis of oral epithelial cells in vitro. The extent to which oral cells recover from toxic resin exposure, the conversion of monomer into polymer, the presence of inorganic filler, and resin leacha~ility have also been studied. It was shown that VLC denture resins inhibit the synthesis of RNA and· DNA relative to a heat-cured resin control (p~0.05). Although epithelial cells appeared to recover from toxic resin exposure, this recovery was inconsistent among experiments. Infrared spectroscopy illustrated chemical group differences that occurred before and after photo-polymerization. Using these differences, the conversion of monomer into polymer ranged from 77% to 97%. This conversion was significantly affected (p< .003) by the type of curing unit, duration of photo-polymerization, and surface exposed to visible light. Soluble substances in cured and uncured resin products were analogous using HPLC. The range of inorganic filler present was 0-15%. These investigations suggest that visible light-cured denture resins may impair the replication of oral epithelial cells. This effect may be related to the leachability of unpolymerized resin constituents, the presence or absence of filler particles, or polymerization by-products.