HOW to RESIZE a DIGITAL CEPH (Updated December 6, 2010)

HOW TO RESIZE A DIGITAL CEPH
(Updated December 6, 2010)

1.  Make sure you have a ceph image with a mm ruler (like the one shown in front of the patient’s forehead below) or a vertical or horizontal object of known size (in cm or mm) on the image. If yours does not have such an object, proceed to step 13 further below:

2.  Open the ceph in Irfanview (or Photoshop if you have that). Irfanview is free, and can be downloaded from here:
http://download.cnet.com/IrfanView/3000-2192_4-10021962.html?tag=mncol;
The instructions below are for Irfanview; Photoshop may be slightly different.

3.  If you see white or gray areas around the image, click and drag your mouse to select the crop selection; then click “Edit” and select “selected crop”.

4.  Click Image, Convert to grayscale.

5.  Click Image, Resize/resample. Change dpi to 96. Click OK.

6.  Again, click Image, Resize/resample. Check “preserve aspect ratio”.

7.  Now take your best guess, and change the width to, say, 600. Click OK:

8.  Click File, Save original folder. Select to save the ceph as TIF type as shown; change the name to something descriptive, like: ceph 600 (assuming you changed its width to 600); and on the TIFF options window, select LZW; then click the Save button:

9.  Open IPSoft. Make sure the right patient has been selected. Open Dentalcad.

10.  Click the “New” button (upper left); the “Import” button (lower left); browse through your folders until you see the image you just saved; then double click it.

11.  Click “Grid on/off” until you see a grid on top of the image. Click the zoom button. Then compare the grid with the ruler on the ceph. Each square on the grid is 1 cm. In this image, we have a perfect match between ruler and grid, so we can be confident that the size is correct:

12.  Do they match? “Match” means: the distance between two cm marks on the ruler is the same as the distance between two cm lines on the grid. The longer the ruler, the more confident you can be that your size is correct. If the answer is yes, then you are done. If the do NOT match, then repeat steps 7-11 until they do.

13.  If your ceph does NOT show mm, then use this method instead:

  1. Place the ceph points and the teeth, then click the Calculate button.
  2. Print the ceph.
  3. On the printout, measure the line from condylion to the A point with a ruler.
  4. Compare that measurement with the "maxillary length" measurement.
    If they match, you have a 1:1 image. But if they do NOT match, then you must resize the ceph image (using Photoshop or Irfanview), then import to DentalCad etc. until they match.

14.  Note the width that produced the best match. If your ceph machine or lab always uses the same settings, then changing to the same width should always produce correctly sized cephs. If not, then you have to repeat the above steps with each new ceph.

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