Table 5. Frequency distribution of the root apex to the IAN measurements.

Range	MRA-I		DRA-I
	N	Ratio (%)	N	Ratio (%)
≤ 2.0	0	0.00	2	1.43
2.1 ‒ 4.0	12	8.57	21	15.00
4.1 ‒ 6.0	31	22.14	37	26.43
6.1 ‒ 8.0	51	36.43	45	32.14
8.1 ‒ 10.0	33	23.57	25	17.86
> 10.0	13	9.29	10	7.14
Total	140	100	140	100

MRA-I/DRA-I: mesial/distal root apex to the inferior alveolar nerve distance