Table 7. Comparison of average scores of OHIP by the grades of IOTN in male patients before and after twelve months of orthodontic treatment.

Male patients
IOTN	OHIP before	OHIP twelve months after	p -Value*
Grade 2	11.21 ± 3.19	5.53 ± 2.76	< 0.001
Grade 3	11.38 ± 3.19	6.25 ± 2.92	< 0.001
Grade 4	11.38 ± 3.70	9.80 ± 3.90	< 0.001

^* Student's t -test.