Comparative clinical investigation of horizontal condylar inclination using the JMA electronic recording system and a protrusive wax record for setting articulators.

PURPOSE

The rationale for recording protrusive mandibular movement is to accurately adjust an articulator. Techniques to record condylar inclination include extraoral tracings and intraoral recording materials. This study compared horizontal condylar inclination angles (HCI) recorded with a protrusive interocclusal record and an electronic pantographic device, the Jaw Motion Analyzer (JMA).

MATERIALS AND METHODS

Twenty-three volunteers (12 females; 11 males; mean age 46.7 years) were selected for this study. First, a protrusive interocclusal wax record after 5 mm protrusive movement was taken from the volunteers and the HCI angles were determined after mounting the volunteers' casts in 2 different articulators (SAM 2; Reference SL). Second, kinematic hinge axis and the HCIs were recorded after 5 mm protrusive movement from protrusive jaw tracks recorded with the JMA. ICC and mean values for HCI were used for statistical analysis. Mean differences of HCI between the measuring methods were compared by Bland Altman Plots.

RESULTS

The agreement of the HCI between the articulators determined by the protrusive record was good. The mean HCI value recorded with the JMA was significantly higher compared to the values of the protrusive wax records. There was no agreement found between the different methods for calculating the HCI.

CONCLUSION

A large variance in articulator settings obtained by interocclusal records is often found. The JMA was found reliable and valid for measuring HCI values. Within the limitations of this study, the use of a pantographic device should be considered for individually adjusting articulators rather than the use of protrusive records.