• Accelerated Calvarial Healing in Mice Lacking Toll-Like Receptor 4

      Wang, Dan; Gilbert, James R.; Cray, James J. Jr; Kubala, Adam A.; Shaw, Melissa A.; Billiar, Timothy R.; Cooper, Gregory M.; Department of Oral Biology; Department of Orthodontics (2012-10-10)
      The bone and immune systems are closely interconnected. The immediate inflammatory response after fracture is known to trigger a healing cascade which plays an important role in bone repair. Toll-like receptor 4 (TLR4) is a member of a highly conserved receptor family and is a critical activator of the innate immune response after tissue injury. TLR4 signaling has been shown to regulate the systemic inflammatory response induced by exposed bone components during long-bone fracture. Here we tested the hypothesis that TLR4 activation affects the healing of calvarial defects. A 1.8 mm diameter calvarial defect was created in wild-type (WT) and TLR4 knockout (TLR4-/-) mice. Bone healing was tested using radiographic, histologic and gene expression analyses. Radiographic and histomorphometric analyses revealed that calvarial healing was accelerated in TLR4-/- mice. More bone was observed in TLR4-/- mice compared to WT mice at postoperative days 7 and 14, although comparable healing was achieved in both groups by day 21. Bone remodeling was detected in both groups on postoperative day 28. In TLR4-/- mice compared to WT mice, gene expression analysis revealed that higher expression levels of IL-1b, IL-6, TNF-a,TGF-b1, TGF-b3, PDGF and RANKL and lower expression level of RANK were detected at earlier time points (# postoperative 4 days); while higher expression levels of IL-1b and lower expression levels of VEGF, RANK, RANKL and OPG were detected at late time points (. postoperative 4 days). This study provides evidence of accelerated bone healing in TLR4-/- mice with earlier and higher expression of inflammatory cytokines and with increased osteoclastic activity. Further work is required to determine if this is due to inflammation driven by TLR4 activation.
    • ACRYLATE/METHACRYLATE CONTENT AMONG A VARIETY OF 3D PRINTING RESINS

      Walker, Dylan; Villalobos, V; Rueggeberg, FA; Brenes, C; Department of Restorative Sciences, Department of General Dentistry (Augusta University, 2019)
      The purposes of this research were to apply an infrared spectroscopic analytical method to differentiate among a variety of commercial, 3D dental printable resins for their acrylate or methacrylate content, and to relate that knowledge to the intended use of the printed item: extraorally or intraorally.
    • Adjunct Post-Operative Analgesia Following Uncomplicated 3rd Molar Removal

      Benton, Bryan; James, J; Department of Oral and Maxillofacial Surgery (Augusta University Libraries, 2019)
      Extraction of 3rd molars is a routine procedure performed in Oral and Maxillofacial Surgery practices. Postoperative analgesia and recovery is a primary concern for patients undergoing removal of 3rd molars. Uncontrolled postoperative pain has been shown to interfere with quality of life, delay recovery, and even contribute to long term unfavorable sequelae of surgery such as chronic pain. Extraction of 3rd molars is widely performed on an outpatient basis and thus postoperative analgesia is patient directed, often with assistance from narcotic analgesics, NSAIDs, or a combination of these. Prescription drug abuse is a public health crisis in the United States. In 2016, 42,249 persons died of an opioid related drug overdose. Narcotic use following surgical procedures can lead to dependency and addiction. In 2016, new persistent opioid use after surgical procedures was 5.9% - 6.5%, this was similar for both minor and major surgical procedures.
    • 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.
    • Alterations in Articular Cartilage of the Rabbit Mandibular Condyle Following Surgical Induction of Anterior Disc Displacement: Light and Electron Microscopic Immunocytochemistry Using Colloidal Gold Conjugates

      Choi, Won-Seok; Department of Oral Biology (1996-05)
      The purpose of this study was to test the hypothesis that surgical induction of anterior disc displacement (ADD) in the rabbit craniomandibular joints (CMJ) will lead to degenerative osteoarthritic changes detectable a t the molecular, subcellular and cellular levels in the articular cartilage of the rabbit mandibular condyle. Ultrastructural features of the normal rabbit mandibular condyle were compared to those of experimental condyles a t two weeks following induction of ADD. The quantities of type-VI and -IX collagens, as well as the components of proteoglycans, such as chondroitin-4-sulfate (C4S), chondroitin-6-sulfate (C6S), k e ra tan sulfate (KS) and link protein (LP) were measured using immunogold labeling technique at the light and the electron microscopic levels. The right joint of each of 20 rabbits was exposed surgically, and all discal attachments were severed except for th e posterior attachment. The disc was then displaced anteriorly and sutured to the zygomatic arch. The left joint served as a sham -operated control. Ten additional joints were used as non­ operated controls. Deeply anesthetized rabbits were perfused with 2% buffered formalin two weeks after surgery. The mandibular condyles were excised and decalcified in ethylenediam inetetraacetic acid (EDTA). Paraffin embedded tissues were sectioned a t 5 (im for light microscopic study, while water-soluble plastic embedded sections were used for electron microscopy. Sections were incubated in monoclonal antibodies directed against C4S, C6S, KS and LP, and in polyclonal antibodies against type-VI and -IX collagens. After incubation in the appropriate colloidal gold conjugated secondary antibodies, tissue sections were studied with light and electron microscopes. In addition, immunostaining for proliferating cell nuclear antigen (PCNA) was performed using paraffin sections, and the PCNA indices of control and experimental condyles were determined. Pathological alterations were obvious in the experimental condyles, and appeared to be characteristic osteoarthritic changes. These include cartilage neovascularization, chondrocyte clustering, vacuolation, loss of extracellular matrix next to the membranes of chondrocytes, and an increase in num ber of apoptotic chondrocytes. Increased num bers of PCNA-positive cells in the osteoarthritic cartilage of the experimental group indicated a n active chondrocytic proliferation. Ultrastructural changes in injured chondrocytes included increased amounts of RER and Golgi, suggesting an increase in the synthesis and secretion of possibly degradative enzymes with a decrease in the normal secretory products. The results of th e immunocytochemistry using colloidal gold conjugates both a t the light and electron microscopic levels showed statistically significant depletion of C4S, C6S, KS, LP, type-VI collagen and type-IX collagen in the osteoarthritic cartilage (P < 0.05). The reduction of binding molecules such as LP, type-VI and type-IX collagens suggest a possible mechanism for the observed loss of integrity of the extracellular matrix. It is concluded that surgical induction of ADD in the rabbit CMJ leads to molecular, cellular and extracellular alterations in the articular cartilage of the mandibular condyle similar to those described previously in hum an ADD and in osteoarthritis of other synovial joints. The results of this study provide evidence that the loss of the shock absorber function of the disc, and the exposure of the condyles to overloading may cause the injured chondrocytes to secrete degenerative cytokines as indicated by the loss of proteoglycans, binding collagens and LP. These molecular changes are expressed a t the subcellular and cellular levels as osteoarthritis or degenerative joint disease.
    • 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.
    • 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.
    • Case Selection Criteria for use with Resin-Infiltrative Treatment of Enamel Decalcification

      Raley, N; Clayton, Ashley; Fortson, WM; Deleon, E; Rueggeberg, FA; Department of Orthodontics, Department of Restorative Sciences (Augusta University, 2019)
      Although one of the primary aims for many orthodontic patients is to achieve improvement in their dental esthetic condition, a high percentage of these patients develop unesthetic, white spot lesions (WSL) during the course of treatment. These lesions develop due to enamel decalcification resulting from bacterial plaque accumulation around difficult to clean brackets and overlying wires and ligation devices. Acids produced locally in this retained plaque will decalcify enamel along the peripheral border of the bonded bracket. Quite often, despite repeated admonishment by the clinician to the patient to take extra care in cleansing these susceptible locations, patients return with large plaque deposits around the brackets, and evidence of the early stages of enamel decalcification: the so-called “white spot lesion” (WSL). The problem becomes obvious at the time of bracket removal, when, although the teeth may now be arranged in near-to-perfect alignment and occlusion, large, white areas of enamel decalcification are prominently displayed, denoting the exact location of where the bonded bracket used to be.
    • Caspase-14: A novel caspase in the retina with a potential role in diabetic retinopathy

      Al-Shabrawey, Mohamed; Ahmad, Saif; Megyerdi, Sylvia; Othman, Amira; Baban, Babak; Palenski, Tammy L.; Shin, Eui Seok; Gurel, Zafer; Hsu, Stephen; Sheibani, Nader; et al. (2012-07-14)
      Purpose: The purpose of this study was to evaluate caspase-14 expression in the retina under normal and diabetic conditions, and to determine whether caspase-14 contributes to retinal microvascular cell death under high glucose conditions.
    • Cellular and Immunocytochemical Response to Mandibular Distraction Using an Implanted Lengthening Device

      Elbokle, Nadar N; Department of Oral Biology (2004)
      Distraction osteogenesis (DO) is a biologic process that generates new bone between surfaces of bone segments, which are gradually separated by traction forces. It is a uniquely effective method with multiple applications in the craniofacial region. This concept has been the basis of all bone-lengthening operations; it involved an osteotomy of the shortened bone and an external/internal fixator device, which slowly elongates the bone to its new dimension while a bony callus is being formed at the side to distraction. The biology of DO is similar to callus fracture healing. The bony regenerate passes through the same phases: formation of a collagen fibril template, mineralization, bony union and finally remodeling. The mechanisms by which the mechanical stresses applied to the bone tissue cause the cells to proliferate and form new bone are not well understood. More studies are needed to understand the cellular events underlying DO and the effects of the strains applied during DO on cellular proliferation and mineral apposition.
    • 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.
    • Characteristics of inflammation common to both diabetes and periodontitis: are predictive diagnosis and targeted preventive measures possible?

      Hanes, Philip J.; Krishna, Ranjitha; Department of Periodontics (2010-04-3)
      Keywords: Periodontitis
    • Clinical Guide for Intraosseous Pathology

      Malik, M; Kalathingal, S; Cullum, A; Buchanan, A; Abdelsayed, A; Kurago, Z; Department of Oral Biology & Diagnostic Sciences, Center for Instructional Innovation (Augusta University, 2019)
      To provide a reference database for dental students to describe and analyze intra osseous pathology that aid to develop a list of differential diagnoses for various diseases affecting the maxillofacial region on patients treated in student clinics. The online database will serve as a resource for descriptive terminology and samples to demonstrate the origin of the lesion, radiographic appearance, borders, contents, effects on adjacent structures, etc. which are the fundamental elements that guide a clinician in developing an impression and formulate the differential diagnosis. Histopathologic evaluation that provides the final diagnosis of each disease process will also be included to demonstrate that radiographic presentation of various disease categories may be similar, however, clinical management is ultimately decided by the tissue sample from the biopsy specimen. The interactive database will have various features that enable the user to access a comprehensive glossary list, word- defined searches, a brief overview of the most common diseases affecting dento-alveolar regions and learn about the management strategies.
    • Conservative Porcelain Veneer: Step by step protocol for ideal preparation

      Wooten, Rebekah; Coleman, J; Pruett, M; Romeo, M (Augusta University, 2019)
      Since the 1930s laminate veneers have been commonly used to improve appearance of teeth, but they did not become popular until enamel etching and porcelain surface treatments made them more clinically predictable in the 1980s.1 Over the years, they have been indicated to modify the color, shape, length and alignment of teeth to improve their esthetic appearance. Contraindications include severely discolored teeth and lack of enamel remaining to support the restoration.3 Treatment planning is the first step to ideal veneer preparation, which involves determining the incisal edge position, shape and proportions of the teeth being restored. This information is obtained form the diagnostic wax-up and subsequent esthetic mock-up. Veneer preparations often follow one of two common reduction patterns: conservative or standard. The difference between the two being the amount of tooth structure removed. The conservative approach involves reduction of 0.3 mm gingival third, 0.5 mm middle third, and 0.7 mm incisal third; or no reduction may be required. The standard preparation typically follows a reduction pattern of 0.8 mm gingival, 1.0 mm middle, and 1.2 mm incisal. Incisal reduction can be characteristic of either technique to allow room for the addition of incisal effects such as halo and translucency. In order to ensure porcelain veneers have the maximum lifetime expectancy, it is imperative to have preparations entirely in enamel. Bonding porcelain veneers to enamel increases their fracture strength. 2 Based on the best available evidence the ten year survival rate for porcelain veneers is at around 95% if bonded to enamel.1 Maxillary midline diastemas (MMD) are present in 28% of the population, and 87.5% of females with a midline diastema are dissatisfied and seek treatment.3 This clinical report focuses on the clinical management of a maxillary midline diastema (MMD) with porcelain veneers through a conservative preparation and incisal reduction.
    • Correlation of Deph of Solvent Resistance with Monomer Conversion

      Keller, Elizabeth; Rueggeberg, Frederick A.; Department of Restorative Sciences (2017-03)
      In the mouth, inadequately cured dental restorative materials may lead to detrimental consequences in their longevity. As light travels through these photo-curable restorative composites, there is an exponential decrease in light penetration with depth, and therefore the extent of local polymerization is compromised. This phenomenon is termed the “Depth of Cure” issue, which restricts the thickness if increment that each restorative material can be placed and polymerized. The purpose of this research is to develop an easily performed test that provides a correlational value between visually identifiable transition zones within acetone-sonicated, sectioned, cured composite specimens and the extent to which a composite has reached maximal monomer conversion values, to ultimately determine adequacy of polymerization at the depth of cure for certain restorative materials. This test method, proven to be independent of composite type, will be submitted to the working group associated with the revision of the International Organization for Standards Organization 4049 standard, for consideration of further testing and perhaps replacement of the current method. This research provides a fulfillment of the requests from well-respected dental clinicians to provide a clinically relevant and meaningful depth of cure test.
    • Dentin Sialophosphoprotein (DSPP) Gene-Silencing Inhibits Key Tumorigenic Activities in Human Oral Cancer Cell Line, OSC2

      Joshi, Rajeshree; Tawfik, Amany; Edeh, Nneka; McCloud, Veronica; Looney, Stephen W.; Lewis, Jill; Hsu, Stephen; Ogbureke, Kalu U.E.; Department of Oral Biology; Department of Pathology; et al. (2010-11-12)
      Background: We determined recently that dentin sialophosphoprotein (DSPP), a member of the SIBLING (Small integrin-binding ligand N-linked glycoproteins) family of phosphoglycoproteins, is highly upregulated in human oral squamous cell carcinomas (OSCCs) where upregulation is associated with tumor aggressiveness. To investigate the effects of DSPP-silencing on the tumorigenic profiles of the oral cancer cell line, OSC2, short-hairpin RNA (shRNA) interference was employed to silence DSPP in OSC2 cells.
    • Differential effects of taurine treatment and taurine deficiency on the outcome of renal ischemia reperfusion injury

      Mozaffari, Mahmood S.; Abdelsayed, Rafik; Patel, Champa; Wimborne, Hereward J. C.; Liu, Jun Yao; Schaffer, Stephen W; Department of Oral Biology; Department of Oral Health and Diagnostic Sciences (2010-08-24)
      Taurine possesses membrane stabilization, osmoregulatory and antioxidant properties, aspects of relevance to ischemic injury. We tested the hypothesis that body taurine status is a determinant of renal ischemic injury. Accordingly, renal function and structure were examined in control (C), taurine-treated (TT) and taurine deficient (TD) rats that were subjected to bilateral renal ischemia (60 min) followed by reperfusion (IR); sham operated rats served as controls. Baseline urine osmolality was greater in the TD group than in the control and the TT groups, an effect associated with increased renal aquaporin 2 level. The IR insult reduced urine osmolality (i.e., day-1 post insult); the TD/IR group displayed a more marked recovery in urine osmolality by day-6 post insult than the other two groups. Fluid and sodium excretions were lower in the TD/IR group, suggesting propensity to retention. Histopathological examination revealed the presence of tubular necrotic foci in the C/IR group than sham controls. While renal architecture of the TD/IR group showed features resembling sham controls, the TT/IR group showed dilated tubules, which lacked immunostaining for aquaporin 2, but not 1, suggestive of proximal tubule origin. Finally, assessment of cell proliferation and apoptosis revealed lower proliferation but higher apoptotic foci in the TT/IR group than other IR groups. Collectively, the results indicate that body taurine status is a major determinant of renal IR injury.
    • 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.