ortho - the international C.E. magazine of orthodontics

ortho1_2013 I 09 C.E. article_ orthognathic surgery I Fig. 5_Overlaid soft tissue on top of hard tissue. Fig. 6_ Establishing the true vertical line based on natural head position. Fig. 7_ Glabella to subnasale (SN). Using soft-tissue markers with 3-D facial map- ping, we are able to diagnose the soft tissue, and we can also relate it to the hard tissue. In Figure 5, 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 seeamarkerthatwecallahingeaccessmarker,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 hori- zontal. 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 6 shows how these two corners are at 90 degrees from each other. In this analysis, we’re go- ing to record all the soft-tissue measurements, both horizontalandvertical,andwe’regoingtobasethem onthelinethatrunsthroughthesubnasale(SN).This establishes the true vertical line based on natural head position. Furthermore, we’re including a few hard-tissue measurementsthatwilltellusaboutthearchitecture of the mandible. These come from Rickets and from theJarabakanalysis.Withthisanalysis,wecancover the basis that we need for orthodontics, but we can also cover what we need in a surgical workup. We also need a frontal analysis, which is taken fromthepatient’sface.Mostofthefrontalworkupis 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 mandibular plane, which we may also find is canted. Thisisespeciallytrueincaseswherethere’sadegen- erative 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. 7). To do so, we have the patient stand in front of a mirror. First, the patient is askedtoclosehiseyesandbobhisheadupanddown three times. Afterthisiscomplete,thepatientisaskedtoopen his eyes and look himself directly in the eyes in the mirror. After we have established the natural head position, we then use the measurement gauge. Our goalistomakesurethelevelingbubbleisinthelines. Thiswillallowustotakeameasurementfromthetrue vertical line to glabella. Fig. 5 Fig. 6 Fig. 7