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

Table 1 PubMed search strategy

No.	Search history	Limits	Results
I	(Root canal therapy or root canal preparation) and root fracture	Human	1014
		Chinese or English
		All years
II	(Nickel-titanium rotary instrument or manual stainless steel instrument) and root fracture	Human	27
		Chinese or English
		All years
III	(Hand instruments or rotary instruments) and root fracture	Human	32
		Chinese or English
		All years
Total			1073

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