Effects of different root canal preparation methods on root fracture resistance: A systematic review of the literature

Table 2 The information statistics of included literature

Ref.	Dental notation	Hand preparation numbers	Hand preparation mean	Hand preparation SD	Ni-Ti preparation numbers	Ni-Ti preparation mean	Ni-Ti preparation SD	Ni-Ti instruments taper
Lan et al[7]	Molar	13	10.2	4.4	13	15.7	9.1	0.06
I
Lan et al[7]	Molar	13	10.2	4.4	13	13.2	6.1	0.08
II
Ren et al[8]	Pre-molar	10	308	8.69	10	228	10.19	0.06
Sathorn et al[9]	Incisor	25	113.5	20.2	25	114.9	37.1	0.04
Shi[10]	Pre-molar	8	459.5	163.4	8	436.75	146.58	0.02
I
Shi[10]	Pre-molar	8	459.5	163.4	8	474.25	101.44	0.04
II
Shi[10]	Pre-molar	8	459.5	163.4	8	431.38	90.67	0.06
III
Singla et al[11]	Pre-molar	10	482.78	19.33	10	399.07	13.279	0.12
Zare Jahromi et al[12]	Molar	16	50.33	19.1	16	63.1	25.46	0.06