• 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.
    • 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.
    • EFFECT OF PRINT ANGULATION, MODEL RESIN, AND PRINTER ON DIMENSIONAL ACCURACY OF 3D PRINTED MODELS

      Fantaski, Lincoln; Mettenburg, D; Brenes, C; Rueggeberg, FA; Department of Restorative Sciences, Department of General Dentistry (Augusta University, 2019)
      Recent advances in the application of digital imaging of oral tissues and three-dimensional, additive fabrication techniques have led to a burgeoning industry in dentistry. Over a very short period of time, this technology has greatly improved in terms of level of surface detail reproducibility and dimensional accuracy of printed forms. Initially, thermoplastic extrusion of warmed filaments of various plastic material was used. However, the layer thickness was quite large, and surface feature reproduction was low. With advances in use of photocurable monomer resins and controlled application of photo-activating light wavelengths to provide polymerization of very thin slices of the form image, the reality of providing stoneless models of a patient’s dentition became a physical, and financial reality in private dental practices.
    • EFFECT OF TIP-TO-TARGET DISTANCE ON IRRADIANCE AMONG A VARIETY OF LED LIGHTS

      Klein, Laura; Rueggeberg, FA; Department of Restorative Sciences (Augusta University, 2019)
      Purpose of this research: To measure and compare (1) tip-to-target distance irradiance profiles (2) tip-to-target distance at which irradiance has dropped to 50% of 0-mm value (3) irradiance value at the 50% distance.
    • EFFECT OF WAVELENGTH EXPOSURE SEQUENCE ON COMPOSITE HARDNESS

      Patel, Mohit; Mettenburg, D; Rueggeberg, FA; Cellular and Molecular Biology, Department of Restorative Sciences (Augusta University, 2019)
      To measure and compare composite top and bottom surface microhardness values when using a multi-wave LED curing light emitting simultaneous blue and violet light, or when the sequence of wavelength applications was provided as separate exposures, of similar duration.
    • PHOTOINITIATOR TYPES AMONG A VARIETY OF 3D PRINTING MONOMERS

      Bowerman, Brielle; Rueggeberg, FA; Brenes, C; Department of Restorative Sciences, Department of General Dentistry (Augusta University Libraries, 2019)
      A variety of manufacturing techniques have been used throughout the history of dentistry, in order to fabricate indirect restorations. Formative processes (pouring or pressing items into molds) are used when making conventional dentures, or when pressing ceramics. Recently, subtractive fabrication methods have enabled clinicians to mill a wide variety of ceramic and resin-based blanks directly into final forms, fitting the oral structures with high degrees of precision. Examples of older additive techniques include wax buildups to establish missing tooth structure for fabrication of subsequent cast restorations and the manual layering of powdered porcelains for development of ceramic facings on metallic substrates, or for ceramic veneers themselves. Tremendous advancements have been made in the field of 3D digital printing for many industrially based applications. Advances in research and development have resulted in tabletop 3D printers that produce rapid prototype specimens having very high accuracy and surface feature details. Recently, these advances have resulted in the manufacture and availability of a wide variety of 3D digital printers that dental offices now use to directly fabricate a wide range of restorative appliances (denture bases and teeth, temporary restorations, splints) as well as ancillary devices (impression trays, surgical implant guides, casts, try-in set-ups, and stents). Contemporary dental 3D printing typically involves use of near or true ultraviolet radiation (405 nm & 385 nm, respectively) in order to fabricate the basic desired form from a vat of photo-polymerizable monomers. Subsequent to initial form fabrication, the specimen is alcohol-washed of excess surface monomer, and is then subjected to an additional exposure of strong near/UV light, in order to maximize the polymerization process and provide optimal physical properties, as well as to minimize cytotoxicity resulting from leaching of unreacted, residual monomer within the bulk of the as-printed item.
    • 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.