Comparison of three facebow/semi-adjustable articulator systems for planning orthognathic surgery

Our aim was to measure the steepness of the occlusal plane produced by thre e different semi-adjustable articulators: the Dentatus Type ARL, Denar MkII , and the Whipmix Quickmount 8800, and to assess the influence of possible systematic errors in positioning of study casts on articulators that are us ed to plan orthognathic surgery. Twenty patients (10 skeletal class II, aci d 10 skeletal class III) who were having pre-surgical orthodontics at Liver pool University Dental Hospital were studied. The measurement of the steepn ess of the occlusal plane was taken as the angle between the facebow bite-f ork and the horizontal arm of the articulator. This was compared with the a ngle of the maxillary occlusal plane to the Frankfort plane as measured on lateral cephalometry (the gold standard). The Whipmix was closest to the go ld standard as it flattened the occlusal plane by only 2 degrees (P<0.05), The results of the Denar and Dentatus differed significantly from those of time cephalogram as they flattened the occlusal plane by 5 degrees and 6.5 degrees (P<0.01), respectively. Clinicians are encouraged to verify the ste epness of the occlusal plane? on mounted study casts before the technician makes the model.