Accuracy and tracing time of cephalometric analyses on a tablet or desktop computer : A prospective study

BACKGROUND

This prospective study aimed to evaluate the influence of the computer type (tablet or desktop) on accuracy and tracing time of cephalometric analyses.

METHODS

Dental students used a web-based application specifically developed for this purpose to perform cephalometric analyses on tablet and desktop computers. Landmark locations and timestamps were exported to measure the accuracy, successful detection rate and tracing time. Reference landmarks were established by six experienced orthodontists. Statistical analysis included reliability assessment, descriptive statistics, and linear mixed effect models.

RESULTS

Over a period of 8 semesters a total of 277 cephalometric analyses by 161 students were included. The interrater reliability of the orthodontists establishing the reference coordinates was excellent (ICC > 0.9). For the students, the mean landmark deviation was 2.05 mm and the successful detection rate for the clinically acceptable threshold of 2 mm suggested in the literature was 68.6%, with large variations among landmarks. No effect of the computer type on accuracy and tracing time of the cephalometric analyses could be found.

CONCLUSION

The use of tablet computers for cephalometric analyses can be recommended.

The Position of the Virtual Hinge Axis in Relation to the Maxilla in Digital Orthognathic Surgery Planning-A k-Means Cluster Analysis

The aim of this study was to investigate a possible relation between skeletal phenotypes and virtual mounting data in orthognathic surgery patients. A retrospective cohort study including 323 female (26.1 ± 8.7 years) and 191 male (27.9 ± 8.3 years) orthognathic surgery patients was conducted. A k-means cluster analysis was performed on the mounting parameters: the angle α between the upper occlusal plane (uOP) and the axis orbital plane (AOP); the perpendicular distance (AxV) from the uOP to the hinge axis; and the horizontal length (AxH) of the uOP from upper incisor edge to AxV, with subsequent statistical analysis of related cepalometric values. Three clusters of mounting data were identified, representing three skeletal phenotypes: (1) balanced face with marginal skeletal class II or III and α=8∘, AxV = 36 mm and AxH = 99 mm; (2) vertical face with skeletal class II and α=11∘, AxV = 27 mm and AxH = 88 mm; (3) horizontal face with class III and α=2∘, AxV = 36 mm and AxH = 86 mm. The obtained data on the position of the hinge axis can be applied to any digital planning in orthognathic surgery using CBCT or a virtual articulator, provided that the case can be clearly assigned to one of the calculated clusters.