Skills analysis of a class I amalgam restoration in a mandibular right first molar.

1. Students changed their body position 32% more often than instructors during amalgam condensation. 2. Experienced instructors used 38% fewer strokes than students to condense the amalgam. 3. On the average, instructors used 65% less time per condensation stroke than students. This was not due to ability to move the instrument more quickly, since both students and instructors had similar minimum stroke times, but rather to the fact that instructors performed slowly less often. 4. The upstroke during condensation required nearly the same time for both students and instructors (an eight percent difference). It was the downstroke that was greatly different (a 96% difference). 5. Instructors repeated condensation strokes 22% more often than students, working more systematically with less "jumping around" in the cavity. 6. The total number of carving strokes was not related to experience. 7. Students repeated carving strokes more often than instructors. 8. Students and instructors tended to use the same length of strokes in carving. 9. There was a noticeable difference between instructors and students in the method used to grasp the instruments.