The University of Iowa colleges of dentistry and engineering are collaborating to build an effective but low-cost surgical simulator that uses force feedback to teach and assess the tactile skills of dentistry. A prototype simulator was built, and a formative evaluation examined the realism of the haptics and identified directions for future work. Using a cross-over design, twelve experienced practitioners probed two virtual teeth using two instruments attached to the force feedback device. The session was videotaped, the forces recorded, and a standardized questionnaire completed. Two analyses were conducted: an ANOVA examined practitioners' questionnaire responses, and a t-test analyzed the probing forces. Significant tooth order by instrument order interaction and instrument effects were found. Practitioners were generally satisfied. They preferred a standard joystick to an explorer, felt that two-dimensional graphics were sufficient, and emphasized that the existing vibration be eliminated. Random placement of caries should help teach generalized skills.