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ePaper created 2014-10-07, 09:31:41 | version 1.30.01
CE article _ orthognatic surgery I If you use hard structure to determine soft-tissue corrections,thenyou’llcomeupshortofgoodfacial aesthetics. That’s why a soft-tissue analysis is so important Using soft-tissue markers with 3-D facial map- ping,weareabletodiagnosethesofttissue,andwe can also relate it to the hard tissue. In Figure 4, we’ve overlaid the soft tissue on top of the hard tissue. With the markers on, after we convert it to a two-dimensional X-ray, we can see where the sub-pupal area is, where the cheekbones are and where the alar base is. In addition, you will see a marker that we call a hinge access marker, which comes from establishing the true hinge axis of the patient. There is also a marker that’s placed on the nose that we call the horizontal point. We are going to analyze everything from a basic coordinate system of a true vertical to an axis horizontal. The image is orientated from the axis horizontal plane and the true vertical plane, which is based on the patient’s natural head position. Figure 5 shows how these two corners are at 90 degrees from each other. In this analysis, we’re going to record all the soft-tissue measurements, bothhorizontalandvertical,andwe’regoingtobase them on the line that runs through the subnasale (SN). This establishes the true vertical line based on natural head position. Furthermore, we’re including a few hard-tissue measurements that will tell us about the architec- ture of the mandible. These come from Rickets and fromtheJarabakanalysis.Withthisanalysis,wecan cover the basis that we need for orthodontics, but wecanalsocoverwhatweneedinasurgicalworkup. We also need a frontal analysis, which is taken from the patient’s face. Most of the frontal workup is done in examining the patient clinically. This enables us to look at the orbital rim, cheekbone, sub-pupil, alar bases, nasal bases and canthus of the eyes. All of this enables us to assess if we have trans- verse asymmetries, where the occlusal plane is canted instead of level. This also holds true with the mandibularplane,whichwemayalsofindiscanted. This is especially true in cases where there’s a degenerative process happening in one joint. _Head position, profile and frontal analysis The natural head position is different for each in- dividualpatient.Thiswillmakethedistancerecorded for Glabella to the true vertical line different. To measure how far Glabella is from SN (true vertical line), we first need to establish the patient’s natural head position (Fig. 6). To do so, we have the patient stand in front of a mirror. First, the patient is asked to close his eyes and bob his head up and down three times. Fig. 5_ Establishing the true vertical line based on natural head position. Fig. 6_Glabella to subnasale (SN). Fig. 7_Establish the horizontal position. Fig. 8_Surgical treatment objective. Fig. 9_Completed the extrusion of the maxillary segment and balanced the occlusal plane. Fig. 10_Establishing the true vertical line. I 09cone beam3_2014 Fig. 10Fig. 9 Fig. 7Fig. 6Fig. 5 Fig. 8 CBE0314_06-15_Freeland 30.09.14 14:13 Seite 4