[The measurement of cutting forces in full crown preparation with three-dimensional transducer unit]

To measure the cutting forces applied by clinicians during preparing full crown and to provide basic data for the training of dentistry in a virtual reality.

Each of six prosthodontists and six dental students prepared three extracted maxillary premolars. The cutting forces were measured with a three-dimensional transducer unit. Differences in cutting time and forces between groups were analyzed with independent-samples t-test.

The cutting forces varied in the range from 0.10 N to 4.90 N. The average cutting force (1.71 N) of four axial surfaces was higher than that (0.45 N) of occlusal surface (including functional cusp inclines) (P < 0.01). The cutting time by prosthodontists was shorter than that by the students (P < 0.05). Moreover, the vertical component of the cutting force was higher than the horizontal one (P < 0.01).

The magnitude of cutting forces could be greatly influenced by the motion direction and tendency of the handpiece. The data on cutting forces might serve as the foundation of cutting simulation algorithm for training in a virtual reality.