Yes you are being shafted, there is a list of dental/orthodontology charges and it shows a "taxpunktzahl" (PP). For a checkup and diagnosis it should be between 25-34 PP, you then have to find out the "Taxpunktwert" for the orthodontologist you visited, I heard the maximum allowed here is CHf 5.80. The 2 multiplied together should be the total cost which should make it a max. of CHf 197.20
The detailed bill will show exactly how many PP he is asking for for each detail of your visit.
If he only took a look and didn't actually give you any treatment then the cost should only be that for the checkup, the diagnosis was "everything is ok"...... Ask your dentist for their Tarif list and see how many PP is listed for the checkup. Also ask for the Taxpunktwert of the Orthodontologist.
If you understand German Goddess go to
www.sso.ch they set the maximum costs for all dental treatment here.