The rotation of a tissue-borne RDP during function is directionally around how many axes?

The rotation of a tissue-borne removable partial denture (RPD) during function occurs around three axes. This is primarily due to the flexible and dynamic nature of the supporting tissues and the design of the RPD itself, which allows for movement in multiple directions during functional activities such as chewing.

In the context of biomechanics, the three axes of rotation typically refer to:

1. The transverse axis (horizontal rotation), which allows for anterior-posterior movement.

2. The sagittal axis (vertical rotation), which facilitates lateral movements.

3. The frontal axis (vertical rotation), which permits movements that might pivot around the height of the occlusal plane.

These rotations enable the RPD to adapt to the changes occurring in the mouth during function, providing stability and comfort while accommodating the stresses exerted on the prosthesis. The ability of the RPD to rotate about these three axes ensures that it can function effectively during mastication and speech, thus enhancing its performance and user satisfaction.