Occlusal plane discrepancies generated by transverse horizontal axis deviations.
BACKGROUND
Any deviation from the patient's rotational axis of the mandible during closure and the arc of closure on an articulator has been reported to produce occlusal discrepancies. These discrepancies can affect diagnostic planning procedures and the occlusal relationships of restorations.


OBJECTIVE
This study investigated the magnitude and types of occlusal errors produced by deviations between the patient's transverse horizontal axis and the axle on the articulator.


METHODS
A simplified monoplane model was diagrammatically analyzed for deviations from the model's true transverse horizontal axis. Axis deviations of 5 mm were used in 8 different directions from the true transverse horizontal axis of the model. Changes in the orientation of the mandibular plane to the maxillary plane were illustrated diagrammatically. These changes were quantified by geometric and trigonometric assessments.


RESULTS
All axis deviations produced mandibular plane orientation errors with angular plane malalignment to the maxillary plane on complete closure. These axis deviations also produced anterior-posterior shifting of the mandibular plane relative to the maxillary plane.


CONCLUSIONS
Several different types of planar shifting and angular discrepancies were demonstrated from deviations away from the true transverse horizontal axis.
Bowley
J F
JF
Faculty of Dentistry, Kuwait University Health Sciences Center, Jabriya, Kuwait. johnbowley@hsc.kuniv.edu.kw
Morgano
S M
SM
D003198:Computer Simulation; D003725:Dental Articulators; D003766:Dental Occlusion; D006801:Humans; D007574:Jaw Relation Record / Q000295:instrumentation / Q000379:methods*; D008334:Mandible / Q000033:anatomy & histology / Q000502:physiology; D008437:Maxilla / Q000033:anatomy & histology; D008954:Models, Biological; D012399:Rotation; D013223:Statistics as Topic; D014716:Vertical Dimension