Occlusal errors generated at the maxillary incisal edge position related to discrepancies in the arbitrary horizontal axis location and to the thickness of the interocclusal record.

Statement Of Problem: Determining the arbitrary transverse horizontal axis by using anatomic landmarks is a simpler clinical procedure than locating the kinematic transverse horizontal axis; however, accuracy may vary depending on individual patient anatomy.

Purpose: The purpose of this study was to investigate an arbitrary transverse horizontal axis relative to the maxillary incisal edge and to examine the magnitude of occlusal error produced when this arbitrary transverse horizontal axis is used to mount casts in an articulator.

Material And Methods: Seventy-three adults (43 men, 30 women) participated in this study. The distance of the arbitrary transverse horizontal axis to the maxillary central incisal edge was measured for each participant. A parametric linear regression was used to analyze the effect of sex on the distance of the arbitrary transverse horizontal axis to the maxillary central incisal edge by using statistical software (SPSS v19.0; SPSS Inc). A linear correlation analysis was used to compare the distance from the arbitrary transverse horizontal axis to the maxillary central incisal edge with the participant's height (α=.05). Four distances from the arbitrary transverse horizontal axis to the maxillary central incisal edge (80, 90, 110, 120 mm) and 3 interocclusal record thicknesses (1, 2, 3 mm) were mathematically calculated to examine the magnitude of occlusal error at the central incisor contact.

Results: The mean distance from an arbitrary transverse horizontal axis to the maxillary central incisal edge position was 100.12 (SD 5.33) mm for all participants. Overall, 89.04% of the participants fell within 5 mm of the 100-mm distance. No significant differences in the distance of the arbitrary transverse horizontal axis to the maxillary central incisal edge position were identified between men and women or with the participant's height. The magnitude of occlusal error at the central incisor contact ranged from 0.45 to 11.26 μm.

Conclusions: The distance from an arbitrary transverse horizontal axis to the maxillary central incisal edge position was not influenced by the sex or height of the participants investigated. Variations in the distance from an arbitrary transverse horizontal axis to the maxillary central incisal edge resulted in minor occlusal discrepancies at the central incisor contact.