Ralph DeLong

Ralph DeLong

Academic Title

Department of Restorative Sciences
Member: Minnesota Dental Research Center for Biomaterials and Biomechanics


Physics and Mathematics, BS, University of Nebraska, 1966
Fixed and Removable Prosthodontics, MS, University of Minnesota, 1981
Nuclear Physics, Ph.D., University of Minnesota, 1974
Other Education
Clinical Dentistry, Doctor of Dental Surgery (DDS), University of Minnesota, 1978

Contact Info




Office Address

16-212 Moos Tower
515 Delaware St. SE
Minneapolis, MN 55455

Bio Statement

Dr. DeLong is a Professor in the Department of Restorative Sciences, and a member of the Minnesota Dental Research Center for Biomaterials and Biomechanics (MDRCBB).

Dr. DeLong's expertise in physics and dentistry led to the development of A.R.T. (Artificial Resynthesis Technology), an oral simulation environment, which is often referred to as the "Artificial Mouth." The Journal of Research & Development chose it as one of the 100 most significant new technical products of the year. Along with co-developer, Dr. William H. Douglas, Dr. DeLong received the "I.R. 100 Award" for the development of a "Biomaterials Evaluation System (Oral)" in 1983.

Dr. DeLong also developed a software program, AnSur? (Reagents, Univ. of MN), that could take data from a 3D surface digitizer and use it to measure surface changes with time. The addition of an optical digitizer spurred the development of the "Virtual Dental Patient" (VDP). In 1997, Dr. DeLong received a NIH/NIDCR grant to test the hypothesis that a virtual computer rendition of a dental patient (VDP) and its clinical source are closely correlated over a wide range of clinical conditions.

In 2004, Dr. DeLong became the Director of the Minnesota Dental Research Center for Biomaterials and Biomechanics (MDRCBB). Established as an industrial/academic collaboration, with the 3M Foundation and 3M Dental Products Division providing the founding funds, the MDRCBB works with industry on the development of new dental biomaterials. New materials are evaluated using technologies in the MDRCBB to determine their applicability and chances for clinical success in the oral cavity. The MDRCBB has been continuously funded since 1991.

Research Interests

The Virtual Dental Patient - Patient specific, accurate 3D representations of articulated upper and lower jaws and their relative movements.

Clinical measurement using 3D digitizing and computer graphics

Robotics and its application to simulation of an artificial oral environment


Member, Phi Kappa Phi Honorary Society

Member, Omicron Kappa Upsilon Honorary Dental Society

I.R. 100 Award, Journal of Research and Development, 1983

Fellow, Academy of Dental Materials


Pintado, M.R., DeLong, R., Ko, C.C., Sakaguchi, R.L. and Douglas, W.H. Correlation of noncarious cervical lesion size and occlusal wear in a single adult over a 14-year time span. J. Prosthet. Dent. 84: 436-443, 2000.

DeLong, R., Pintado, M.R., Ko, C.C., Hodges, J.S. and Douglas, W.H. Factors influencing optical 3D scanning of vinyl polysiloxane impression materials. J. Prosthodont. 10: 78-85, 2001.

Lai, J.H., Wang, L.L., Ko, C.C., DeLong, R. and Hodges, J.S. New organosilicon maxillofacial prosthetic materials. Dent. Mater. 18: 281-286, 2002.

Ko, C.C., Swift, J.Q., DeLong, R., Douglas, W.H., Kim, Y.I., An, K. N., Chang, C. H. and Huang, H. L. An intra oral hydraulic system for controlled loading of dental implants. J. Biomech. 35: 863-869, 2002.

DeLong, R., Ko, C.C., Olson, I., Hodges, J.S. and Douglas, W.H. Helical axis errors affect computer-generated occlusal contacts. J. Dent. Res. 81: 338-343, 2002.

DeLong, R., Ko, C.C., Anderson, G.C., Hodges, J.S. and Douglas, W.H. Comparing maximum intercuspal contacts of virtual dental patients and mounted dental casts. J. Prosthet. Dent. 88: 622-630, 2002.

Ko, C.C., Douglas, W.H., DeLong, R., Rohrer, M.D., Swift, J.Q., Hodges, J.S., An, K.N. and Ritman, E.L. Effects of implant healing time on crestal bone loss of a controlled-load dental implant. J. Dent. Res. 82: 585-591, 2003.

Chang, M.C., Ko, C.C., Liu, C.C., Douglas, W.H., DeLong, R., Seong, W.J., Hodges, J. and An, K.N. Elasticity of alveolar bone near dental implant-bone interfaces after one month's healing. J. Biomech. 36: 1209-1214, 2003.

DeLong, R., Heinzen, M., Hodges, J.S., Ko, C.C. and Douglas, W.H. Accuracy of a system for creating 3D computer models of dental arches. J. Dent. Res. 82: 438-442, 2003.

Tantbirojn, D., Versluis, A., Pintado, M.R., DeLong, R. and Douglas, W.H. Tooth deformation patterns in molars after composite restoration. Dent. Mater. 20: 535-542, 2004.

Versluis, A., Tantbirojn, D., Pintado, M.R., DeLong, R. and Douglas, W.H. Residual shrinkage stress distributions in molars after composite restoration. Dent. Mater. 20: 554-564, 2004.


Minnesota Dental Research Center for Biomaterials and Biomechanics

  • ©2014 Regents of the University of Minnesota. All rights reserved.
  • The University of Minnesota is an equal opportunity educator and employer
  • Last modified on September 18, 2015