Faculty Directory

Ceramic-filled composites for dental applications, biomaterials, ceramics for sensor systems, and undergraduate STEM education.

Ceramic-Filled Composites for Dental Applications

Dental restorations such as fillings and crowns are subject to mechanical fatigue and wear from high cycle point contact loading in the mouth. Our group has explored ceramic filled polymer composites for application as dental joining layers in laminar crowns. When a relatively thick (≥ 10 µm) compliant layer supports an all-ceramic crown, or the layers within a laminar ceramic crown, flexure and failure via radial crack initiation can occur. We have developed a new class of high elastic modulus adhesive composites based on dental resins filled with nano-alumina and micro-diamond fillers to address this problem. We are currently working on extending this work to composites for fillings. Elastic modulus is still a critical property because it is important in helping to transfer the load during chewing from the composite to the tooth. However, strength, toughness and aesthetics are also important. We are working to better understand the effects of surface interactions between fillers and resin and the microstructure of the composite on performance in oral environments to allow us to balance elastic modulus, strength, toughness and aesthetics.

RET (Research Experiences for Teachers) in Engineering: Connecting with Community Colleges

Our RET is the only RET in Engineering to focus on community college faculty and students. Its goal is to increase the interest and success of community college students in STEM classes and careers. Our approach is to integrate community college faculty in cutting edge engineering research that they translate into classroom materials and activities that foster student awareness, interest, and preparation for STEM studies and careers. The program includes biology, mathematics, chemistry, physics and engineering instructors to reach the broadest cross-section of students possible. Twenty-four faculty from six Maryland community colleges have participated at least once in the past three years. The participants have shared their experiences and materials with their colleagues at their home institutions. Six participants have presented their experiences and curriculum elements at three different conferences (AMATYC (American Mathematical Association of Two-Year Colleges), FYEE (First Year in Engineering) and AFFACT (Association of Faculties for Advancement of Community College Teaching). We are in the process of developing a web-based system to share our most successful curriculum elements with community college faculty beyond Maryland.

For more information, see:

Research Experiences for Teachers
"Lloyd Leads Program for Community College Faculty"
"Clark School Wraps 1st Phase of Community College Faculty Program"

• Yang, Y., Pei H., Chen G., Webb, K.T., Martinez-Miranda, L.J., Lloyd I.K., Lu Z., Liu, K., and Nie, Z., Phase behaviors of colloidal analogs of bent-core liquid crystals, Science Advances 4(5) eaas8829 (2018). DOI: 10.1126/sciadv.aas8829
• Saied, M. A., Lloyd, I. K., Haller, W. K., & Lawn, B. R. Joining dental ceramic layers with glass. Dental Materials 27 (10), 1011-1016 (2011).
• Saied, M.A., Wilson, O.C. Jr., Rekow, E.D., & Lloyd, I.K. Design of join glass composition for layered all-ceramic restorations. Journal of the American Ceramic Society 94 (8) 2458-2463 (2011).
• Wang, Y.J. & Lloyd, I.K., Time-dependent nanoindentation behavior of high elastic modulus dental resin composites. Journal of Materials Research 25 (3), 529-536 (2010).
• Lee, J.J.W. et al., Veneer vs. core failure in adhesively bonded all-ceramic crown layers. Journal of Dental Research 87 (4), 363-366 (2008).
• Wang, Y.J. et al., High modulus nanopowder reinforced dimethacrylate matrix composites for dental cement applications. Journal of Biomedical Materials Research Part A 82A (3), 651-657 (2007).
• Lee, J.J.W., Wang, Y., Lloyd, I.K., & Lawn, B.R., Joining veneers to ceramic cores and dentition with adhesive interlayers. Journal of Dental Research 86 (8), 745-748 (2007).
• Lee, J.J.W., Lloyd, I.K., Chai, H., Jung, Y.G., & Lawn, B.R., Arrest, deflection, penetration and reinitiation of cracks in brittle layers across adhesive interlayers. Acta Materialia 55 (17), 5859-5866 (2007).
• Lee, J.J.W., Chai, H., Lloyd, I.K., & Lawn, B.R., Crack propagation across an adhesive interlayer in flexural loading. Scripta Materialia 57 (12), 1077-1080 (2007).
• Donahoe, D.N., Pecht, M., Lloyd, I.K., & Ganesan, S., Moisture induced degradation of multilayer ceramic capacitors. Microelectronics Reliability 46 (2-4), 400-408 (2006).
• Lawn, B.R. et al., Materials design in the performance of all-ceramic crowns. Biomaterials 25 (14), 2885-2892 (2004).
• Xu, G.F., Carmel, Y., Olorunyolemi, T., Lloyd, I.K., & Wilson, O.C., Microwave sintering and properties of AlN/TiB2 composites. Journal of Materials Research 18 (1), 66-76 (2003).
• Quinn, J.B., Sundar, V., & Lloyd, I.K., Influence of microstructure and chemistry on the fracture toughness of dental ceramics. Dental Materials 19 (7), 603-611 (2003).
• Quinn, J.B. et al., Strength and fractographic analysis of chalcogenide As-S-Se and Ge-As-Se-Te glass fibers. Journal of Non-Crystalline Solids 325 (1-3), 150-157 (2003).
• Flanders, L.A., Quinn, J.B., Wilson, O.C., & Lloyd, I.K., Scratch hardness and chipping of dental ceramics under different environments. Dental Materials 19 (8), 716-724 (2003).
• Xu, G.F., Olorunyolemi, T., Wilson, O.C., Lloyd, I.K., & Carmel, Y., Microwave sintering of high-density, high thermal conductivity AIN. Journal of Materials Research 17 (11), 2837-2845 (2002).
• Quinn, J.B., Yen, J., Katz, R.N., & Lloyd, I.K., Subjective ceramic machinability and material properties. Machining Science and Technology 6 (2), 291-299 (2002).
• Olorunyolemi, T. et al., Thermal conductivity of zinc oxide: From green to sintered state. Journal of the American Ceramic Society 85 (5), 1249-1253 (2002).
• Lawn, B.R. et al., Materials design of ceramic-based layer structures for crowns. Journal of Dental Research 81 (6), 433-438 (2002).
• Deng, Y., Lawn, B.R., & Lloyd, I.K., Characterization of damage modes in dental ceramic bilayer structures. Journal of Biomedical Materials Research 63 (2), 137-145 (2002).
• Deng, Y., Lawn, B.R., & Lloyd, I.K., Damage characterization of dental materials in ceramic-based crown-like layer structures. High-Performance Ceramics 2001, Proceedings 224-2, 453-457 (2002).
• Xu, G.F., Lloyd, I.K., Carmel, Y., Olorunyolemi, T., & Wilson, O.C., Microwave sintering of ZnO at ultra high heating rates. Journal of Materials Research 16 (10), 2850-2858 (2001).
• Pert, E. et al., Temperature measurements during microwave processing: The significance of thermocouple effects. Journal of the American Ceramic Society 84 (9), 1981-1986 (2001).
• Quinn, J.B. & Lloyd, I.K., Comparison of methods to determine the fracture toughness of three glass-ceramics at elevated temperatures. Journal of the American Ceramic Society 83 (12), 3070-3076 (2000).
• Nguyen, V.Q., Sanghera, J.S., Lloyd, I.K., Aggarwal, I.D., & Gershon, D., Room temperature dielectric properties of the As40S((60-x))Se-x glass system. Journal of Non-Crystalline Solids 276 (1-3), 151-158 (2000).
• Nguyen, V.Q., Sanghera, J.S., Aggarwal, I.D., & Lloyd, I.K., Physical properties of chalcogenide and chalcohalide glasses. Journal of the American Ceramic Society 83 (4), 855-859 (2000).
• Nguyen, V.Q., Sanghera, J.S., Kung, F.H., Aggarwal, I.D., & Lloyd, I.K., Effect of temperature on the absorption loss of chalcogenide glass fibers. Applied Optics 38 (15), 3206-3213 (1999).
• Nguyen, V.Q., Sanghera, J.S., Freitas, J.A., Aggarwal, I.D., & Lloyd, I.K., Structural investigation of chalcogenide and chalcohalide glasses using Raman spectroscopy. Journal of Non-Crystalline Solids 248 (2-3), 103-114 (1999).
• Wilson, O.C., Quinn, J., Peng, T., Lloyd, I.K., & Thompson, V.P., Environmental effects on material removal and damage in dental ceramics. Journal of Dental Research 76, 3091-3091 (1997).
• Hill, M.D., White, G.S., Hwang, C.S., & Lloyd, I.K., Cyclic damage in lead zirconate titanate. Journal of the American Ceramic Society 79 (7), 1915-1920 (1996).
• Xu, H.H.K., Braun, L.M., Ostertag, C.P., Krause, R.F., & Lloyd, I.K., Failure Modes of Sic-Fiber/Si3n4-Matrix Composites at Elevated-Temperatures. Journal of the American Ceramic Society 78 (2), 388-394 (1995).
• Brower, D.T. & Lloyd, I.K., Investigation of the Effect of Host Composition on the Photoluminescent Properties of Srxba1-Xs Doped with Eu and Sm. Journal of Materials Research 10 (1), 211-213 (1995).
• Benedetto, J.M., Roush, M.L., Lloyd, I.K., Ramesh, R., & Rychlik, B., The temperature dependence of ferroelectric imprint. Integrated Ferroelectrics 10 (1-4), 279-288 (1995).
• Xu, H.H.K., Ostertag, C.P., Braun, L.M., & Lloyd, I.K., Effects of Fiber Volume Fraction on Mechanical-Properties of Sic-Fiber Si3n4-Matrix Composites. Journal of the American Ceramic Society 77 (7), 1897-1900 (1994).
• Xu, H.H.K., Ostertag, C.P., Braun, L.M., & Lloyd, I.K., Short-Crack Mechanical-Properties and Failure Mechanisms of Si3n4-Matrix Sic-Fiber Composites. Journal of the American Ceramic Society 77 (7), 1889-1896 (1994).