Mark Posterior Contacts
When you click the next step, “Mark Posterior Contacts” the screen should resemble the image below (left). At this stage you should begin clicking on or near the high points of each tooth cusp. As you begin clicking after fifteen or so points (this will vary case to case) a red plane will begin to appear. Pictured below, right.
This red plane will be used to remove or ‘scrape’ off the bottom of the wax rim to create a static occlusal surface. This plane represents how much contact the final appliance will have with the teeth when grinding the final MIP. The tan areas of the teeth shown “poking” through the red plane are the areas of the teeth that will leave an impression in the final appliance. The picture below (left) depicts the result of grinding the MIP in the final appliance and would not be visible at this stage. It is, however, the reasoning behind this stage.
Notice the contact points mimic the depth of the tan area depicted in the posterior contact plane.
The height or depth of these contact points can be adjusted by moving the contact points. For less contact drag the point to the highest point on the cusp. For more contact drag the point lower on the tooth. In cases of nearly flat teeth or a curved spee you can add contact points to large contact areas to shrink them, or delete them altogether to avoid too much contact in the posterior. Don’t worry about the protrusion element just yet, we are about to cut out a window in this surface to make sure we don’t flatten it out.
Once you are satisfied with the amount of contact established, we can move on by selecting “Next” at the bottom of the screen. The plane will then turn gray and a new menu will appear giving the option to paint and delete pieces of this plane. Deleting a portion of this plane will prevent the wax in that area from being removed from the rim.
. For the Farrar, the area of the trimming surface will need to be removed on the lingual side of lower anterior teeth. This will allow the wax for the mandibular stop to remain.
After painting the area, select delete painted. The plane will now appear red again, but with the deleted area removed. The next step will be to subtract the posterior plane and should look something like the image below once complete.
