KPG Index versus OPG Measurements: A Comparison between 3D and 2D Methods in Predicting Treatment Duration and Difficulty Level for Patients with Impacted Maxillary Canines

Table 3

Contingency table comparing Stewart’s measurement versus Ericson and Kurol’s analysis.

(a)

Stewart	Ericson and Kurol		Total
	Easy	Difficult
Shorter	42	36	78
Longer	9	18	27
Total	51	54	105

(b) Chi-square tests

	Value	𝑃 value
Pearson correlation (𝑟)	0.179	0.303
χ ^2	0.455	0.500
Positive likelihood ratio	1.235
Negative likelihood ratio	0.529
Sensitivity	0.824
Specificity	0.333
Positive predictive value	0.538
Negative predictive value	0.667