Accurate way of measuring the distance of tooth cusp to CEJ

Hi everyone, recently I need to perform gingivoplasty to a patient with severe gingival hyperplasia. But the first thing I should do before the actual surgery is to mark the CEJ (cement-enamel-joint) on patient’s gingiva. As the image shows, I decide to measure the distance of tooth cusp to CEJ.
For each tooth, I measured 6 points (buccal and palatal, mesial/middle/distal).

But when I tried to used the above data to perform surgery, I found out for the posterior teeth, the actual distance between the tooth cusp to CEJ is greater(1~2mm) to what I measured in the slicer 3D software. I think it might be caused by the curved surface. So I wonder if there is a more accurate way of measuring this kind of distance.

If you want to measure distance along a curved surface then you can place a curve (with multiple points along the curved surface). Instead of placing points along a straight line manually, you can place a curve with just two points and then resample it on a surface using Markups module / Resample (set “Constrain points to surface” to the model node that you exported from the segmentation).

How did you measure the distance during surgery? Instead of making point measurements, using the Segment Editor module you could design a 3D-printable marking guide that you can snap to the teeth of the patient and would only leave the enamel part exposed.