The first division shows 1mm when top of measuring
block and needle are coincide. Wide of graduation is
1mm and pitch is 2mm, thus each graduation shows
the gingival thickness of 2,3,4,5,6,7mm. Put the
measuring block in right angle to gingiva, then prick
gingival by light force until needle reaches to bone. Pull
out carefully so that measuring block would not moves.
Read the thickness at the back side of measuring block.