Comparison Of The Accuracy Of Direct And Indirect Facebow Mountings

Objective:The accuracy of the indirect facebow mounting has been questioned by some clinicians, and may contribute to a significant reference plane error. This study compared the accuracy of indirect hinge axis record transfer to that of a direct transfer. Methods: One healthy white Caucasian male subject was selected as a convenience sample. A maxillary impression was made with a regular set alginate material (JelTrate Plus, Dentsply International, York, PA) cast with Silky Rock Stone (WhipMix Corporation, Louisville, KY) and duplicated three times to make four maxillary casts Three facebow records were made by the same operator on the subject using one of four facebow systems: Hanau H2 (Spring-Bow), Denar Mark II (Slideamatic), SAM 2 (Axioquick), and WhipMix DB 2000 (Quickmount) as the method of hinge axis transfer. Each cast was then mounted on the corresponding manufacturer’s articulator with 12 mountings made using the facebow itself (Direct), and 12 using the indirect mounting jig (Indirect). The maxillary casts were then positioned on the SAM RMI/3D Digitizer (Great Lakes Orthodontics, Tonawanda, NY) and the X, Y, and Z coordinates of three predetermined points were obtained. A One-Way ANOVA was used to determine if differences existed between direct and indirect mounting of the facebow/articulator system in the X, Y and Z axes at á=0.05. Results: No significant differences were found between the direct and indirect measurements on the X axis (p = .889), Y axis (p=1.000) and Z axis (p= .463) for the four facebow systems. Conclusion:The results suggest that the maxillary cast position is not changed if the manufacturers’ direct or indirect articulator mounting method is used.