Trick 48 of the book Tricks and Hints G. Ubassys

How to study and rapidly correct the shape of teeth

To adapt the shape of teeth accurately, it is essential to outline their contours and transition points with a pencil. After having smoothed all the teeth with a soft stone burr (Fig.1), choose a colour, here we have chosen red. Hold the pencil at a tangent to the surface (Fig.2) and slide it over the transition angles and the convexities in the work model (Fig.3 to 5). Notice that the blue pencil was used to outline the outer contour of the teeth. Now we use the blue pencil again, but this time with the tip to draw the desired ideal angles (Fig. 6 to 8).
Wherever the blue is superimposed on the red, this means that the transition angle is correctly positioned, when the blue is shifted, this indicates that a correction is required. Again, we shall use the soft burr to mil and shift the red angle nearer to the blue outline (Fig.9). Thus, very quickly and without tiring our eyes, we shall mill down all the false angles signaled by the red pencil marks, so that they match the blue lines (Fig.10 to 12). To check that our transition angles are now correct, we shall once more shade the angles with our red pencil. (Fig.13).
When all the red and blue tracings are perfectly superimposed, then we can be sure that our transition angles are correctly placed (Fig.14 to 16). Once the restorations are finished and polished, notice how the light is reflected on the angles outlined by the pencil (Fig.17 to 19).
This procedure allows us to save a lot of time and the final result is very precise. The method is very effective.
Another quality of this pencil its his complete calcinations. We can realize ceramic increments on the pencils line (Fig.20), this one will burn without any trace.