Survival Analysis of Factors Influencing Cyclic Fatigue of Nickel-Titanium Endodontic Instruments

Table 2

Results of the Cox proportional hazard model of the cyclic fatigue lifetime of the instruments. The set of reference categories is 3 mm radius, Wizard Navigator, and red ISO colour.

	Estimat.	Stand. error	value	Hazard ratio
5 mm	−5.461	0.476	0.0001	0.004
Mtwo	−3.212	0.394	0.0001	0.040
ProTaper	5.901	0.566	0.0001	365.291
Revo-S	0.583	0.259	0.0250	1.791
yellow	−1.700	0.207	0.0001	0.310