1. Department of Prosthodontics, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina.
2. University of Mount Union, Alliance, Ohio.
3. Department of Pharmacology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina.
4. Department of Prosthodontics, School of Dentistry, and Department of Pharmacology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina.