Table 8. Comparison of average scores of OHIP by the grades of IOTN in female patients before and after twelve months of orthodontic treatment.

Female patients
IOTN	OHIP before	OHIP twelve months after	p -Value*
Grade 2	11.29 ± 3.54	5.97 ± 4.20	< 0.001
Grade 3	12.26 ± 3.08	6.94 ± 3.50	< 0.001
Grade 4	11.90 ± 3.00	9.00 ± 4.81	0.027

^* Student's t -test.