Ultrasonic Jaw Movement Recorder : Reproduction of Articulator Settings and Movements

Aims: The purpose of this study was to investigate the ability of the KaVo Arcus Digma (KAD)to reproduce articulator settings and movements. The KAD is an ultrasonic mandibular movement recorder, which provides articulator setting information for KaVo Protar semi-adjustable articulators. Traditional methods of setting articulators to a high level of accuracy are complex and time consuming, whilst this system is purported to be simple and quick. Methods: The first part of the study examined the ability of the KAD to record condylar control values pre-set on Protar articulators. Using a mechanical pantograph, the second part of the study tested the ability of the KAD to calculate settings for a Protar articulator that would reproduce the movement of a Denar D5A articulator. Results: The difference between pre-set values and those recorded by the KAD ranged between -8.9 to 4.1 degrees (SD = 2.2 degrees) for sagittal condylar inclination (SCI), -11.5 to 10.8 degrees (SD = 3.6 degrees) for progressive side shift (PSS), -1.5 to -0.3mm (SD = 0.35mm) for immediate side-shift (ISS) and -39.3 to 32.5 degrees (SD = 10.45 degrees) for shift angle (SA). Pantographic tracings demonstrated agreement between the movement of the two articulators so long as ISS was not set. Conclusions: The KAD demonstrated a high level of accuracy in recording SCI but was less accurate in recording PSS. The persistent under-provision of ISS may be of clinical concern. Prescribed SA may be a means of compensating for lack of intercondylar width adjustability in Protar articulators.