Table 3.

Frontal sinus width of all samples and pairwise comparison among subgroups

Index	Sex		Dentoskeletal classification			Age			The most convex part of the forehead
	Male	Female	Class I	Class II	Class III	Child	Teenager	Adult	Upper1/3	Middle1/3	Lower1/3
N	204	201	204	127	74	93	160	152	14	187	204
Mean ± SD	0.936 ± 0.291	0.744 ± 0.204	0.849 ± 0.287	0.820 ± 0.277	0.855 ± 0.277	0.766 ± 0.230	0.848 ± 0.250	0.880 ± 0.269	0.757 ± 0.248	0.764 ± 0.217	0.917 ± 0.293
P	<0.001**		0.563			0.005*			<0.001**
Pairwise comparison	Male-Female		I-II	II-III	I-III	C-T	T-A	A-C	U-M	M-L	U-L
	<0.001**		0.340	0.377	0.876	0.019*	0.282	0.001*	0.084	0.000**	0.017*

The N in all categories refers to cases in which the maximum anterior-posterior diameter of the frontal sinus can be traced and measured in the lateral cephalometric radiograph I, II, III; A, T, C; U, M, L: Means Class I, Class II, Class III; Adult, Teenager, Child; Upper, Middle, Lower

SD standard deviation

* Statistical significance (P < 0.05) as determined by the Kruskal-Wallis test and Independent-Samples T-Test

** Highly statistically significant (P < 0.001)