Space planning sensitivity and specificity: Royal London Space Planning and Korkhaus Analyses

To establish the sensitivity and specificity of the Korkhaus and Royal London Space Planning Analyses.

The sample consisted of 30 cases with two sets of study models and lateral cephalometric radiographs taken at least three years apart. These were then further subdivided into Class I (N = 10), Class II division 1 (N = 10) and Class II division 2 cases (N = 10). The Royal London Space Planning Analysis and the Korkhaus Analysis were applied on these cases at both times.

Study model analysis: The Royal London Planning Analysis revealed that in Class I malocclusions, upper and lower arch crowding and spacing changed significantly with time. The total space required and tooth size reduction for the lower arch had also changed significantly. Additionally, in the Class II division 1 malocclusions, lower arch crowding and spacing, total space required and the need for tooth size reduction had significantly increased, while in Class II division 2 malocclusions, a statistically significant increase was observed in the upper and lower arch crowding and spacing. The Korkhaus Analysis showed that in Class I malocclusions, a significant decrease was observed in the lower arch length and the lower anterior arch width. The upper posterior (inter-molar) arch width had significantly increased. In Class II division 1 malocclusions the lower right posterior space available had decreased significantly. The upper posterior arch width and the lower posterior arch width also significantly increased. In Class II division 2 malocclusions, a statistically significant decrease was observed in the lower anterior arch length. There were no significant changes in all angular and the two linear measurements for all classes.

The Royal London Space Planning Analysis and the Korkhause Analysis are clinically sensitive analyses. The Royal London Space Planning Analysis lacks specificity to be a robust model for treatment planning; modification may be required before this technique is accepted.