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 2

Contingency table comparing KPG index versus Ericson and Kurol analysis.

(a)

KPG	Ericson and Kurol		Total
	Easy	Difficult
Easy	48	30	78
Difficult	3	24	27
Total	51	54	105

(b) Chi-square tests

	Value	𝑃 value
Pearson correlation (𝑟)	0.441	0.008*
Yates χ ^2	4.937	0.026^†
Positive likelihood ratio	1.694
Negative likelihood ratio	0.132
Sensitivity	0.941
Specificity	0.444
Positive predictive value	0.615
Negative predictive value	0.889

 *Statistically significant association.
^†Statistically significant rejection of independency.