[The limits of root planing in the furcation area. A mathematical comparison of the radii of curvature on the root surfaces and on the curettes].

In order to draw some conclusions about the furcation region accessibility for periodontal instruments and their cleaning effect, the curvature radii of the root faces of 31 lower molars were mathematically determined and compared with the curvature radii of the working end of normally available curettes. From the results of this work it can be seen, that the Gracey curettes have an essential greater curvature radius as the curvature radius of the root faces. On the other site the special curettes for root planing in the furcation region have a smaller curvature radius as that of the root faces. Using the instruments included in this study, it is not possible to achieve an optimal root planing.