1. The labial surface of the maxillary centrals should be 8-10mm in front of the center of the incisive papilla. (See the "reference" section in the "addendum" at the end of web site.) The incisal edge should be on the occlusal plane.
2. The midline should be taken from a line drawn down the middle of the face. The maxillary centrals should be on that (vertical) line.
So after we set the midline on the wax rim, the student noticed that the centrals were not exactly in the middle of the arch. He/she therefore moved the midline so it would coincide with the median raphe of the palate (or the middle of the incisive papilla). Naturally when we tried in the teeth the midline was off and all the teeth had to be reset.
You should try to get the lower midline to coincide with the upper. However this is not critical. Sometimes it is impossible to line up the midlines because your lower appliance is a partial and the teeth have drifted.
3. No anterior contact.
4. Buccal overjet all the way around the arch. (No overbite.)
5. Set central fossa of mandibular posterior teeth over the crest of the mandibular ridge.
6. Set teeth flat bilaterally, and half way, to two thirds up the pad.
(Check from the lingual to see if the lingual cusps are on the same level as the buccal cusps.)
7. Simultaneous bilateral posterior contact.
8. Contacts of equal intensity around the arch.
9. Group function. (No canine guidance.)
10. With flat teeth there are no cusps or fossa. There can't be an exact cusp to fossa relationship. Some instructors still prefer a very good approximation of cusp to fossa. (I don't.)
11. The occlusal plane should be at about the commissure of the lips. It should also be just below the dorsum of the tongue. (Just follow your occlusion rims is the easiest rule.)
12. When the set-up is complete check the lingual contacts of the maxillary teeth while viewing from the back of the articulator. Frequently they are out of contact. Open the articulator and dig into the lingual wax to pull down the maxillary linguals. Close the articulator so the maxillary teeth will return to proper contact. Fill the holes in the wax to secure the position of the maxillary teeth.
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©1999 by Julius Rosen, D.D.S.