Rella P. Christensen, PhD, RDH, has a doctorate in physiology with an emphasis on microbiology from Brigham Young University. She cofounded Clinical Research Associates in 1976 and was its director for 27 years. She is the team leader of Technologies in Restoratives and Caries Research (TRAC Research), a nonprofit institute dedicated to in-depth, long-term clinical studies of restorative materials, preventive dentistry, and dental caries. She practiced dental hygiene for 25 years and founded the University of Colorado’s dental hygiene program.