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ePaper created 2014-10-07, 09:31:41 | version 1.30.01
I CE article _ orthognatic surgery After this is complete, the patient is asked to openhiseyesandlookhimselfdirectlyintheeyesin the mirror. After we have established the natural headposition,wethenusethemeasurementgauge. Our goal is to make sure the leveling bubble is in the lines. This will allow us to take a measurement from the true vertical line to Glabella. Keep in mind that everybody’s head position is a bit different. The further that Glabella is from the trueverticallinewillaffecthowwelookatthelower third of the face. Now we need to establish the axis-horizontal plane (Fig. 7). First, we establish the horizontal position using the ear bow. We’ll use the pointer on the ear bow to make a mark on the nose when the bow is level. We have previously established, through axio- pathtracing,thehingeaxispositiononthepatient’s right and left sides. In combining the horizontal point with the two axis points, the axis-horizontal plane can be established. The axis-horizontal plane is then transferred to the articulator. This allows us to orientate the CBCT data with the articulator mounting. Now we have the true axis-horizontal plane and the true vertical line combined, and now facial, skeletal and functional issues can be assessed. In the example we are using, the patient has amandiblethathasanarchitectureproblem,which causes her to occlude only on the molars with an anterior open bite. Thisispreciselythekindofcasewhereyoushould be looking for degenerative joint disease. All of the above enables us to establish the parameters and coordinates we need to analyze the face and occlu- sion and then apply the correct treatment so the patientwillhaveafunctioningstableocclusionwith the necessary facial improvements. _Soft-tissue analysis The treatment objectives are based on the soft tissue.Youperformthesurgicaltreatmentobjective in this order. 1) Establish the position of the upper lip to the true vertical line in a vertical and horizontal manner. 2) Determine what you need to do with the anterior teeth to create the correct upper lip position. 3) Once you established the anterior part of the maxilla, then proceed to the posterior part of the maxilla and determine if you need to do an intrusion or extrusion of the posterior segments to level the occlusal plane. In most cases where there’s a retrusive chin and a skeletal open-bite, the patient has an oc- clusal plane, measured from the true vertical line that is somewhere between 102 and 108 degrees. By leveling the occlusal plane, based on the an- terior tooth position, you can set the mandible to the maxilla. This will usually balance the lower third of the face. If you still find the chin is too Fig. 11_Shows true hinges access mounting. Fig. 12_Open bite on hinge axis mounted model. Figs. 13a–h_Diagnostic setup. 10 I cone beam3_2014 Fig. 11 Fig. 12 Fig. 13a–h CBE0314_06-15_Freeland 30.09.14 14:13 Seite 5