Flexibility and Cutting Ability of Stainless Steel Endodontic Instruments
J. WAN, J. GUZMAN, B.L. MUSIKANT, and A.S. DEUTSCH, Essential Dental Systems, South Hackensack, NJ
Objective: To examine the effect of pitch number and cross-sectional area on the flexibility and cutting ability of three stainless steel endodontic instruments used in reciprocation.
Methods: Three brands of size 40/.02 stainless steel instruments twisted from rectangular stainless steel wire were tested: Dentsply K-File, Dentsply Reamer, and SafeSiders. Flexibility was determined according to ISO standard 3630-1:2008. Each sample (12/gp) was bound 3mm from the tip in a torque measurement test stand, and flexibility was recorded as the torque required to deflect each sample through 45°. Cutting ability was determined by preparing anterior teeth to a size 30 and operating on them with each sample (12/gp) with a 4:1 reciprocating handpiece at 2500 rpm for 5 seconds. Loosened debris from cutting and subsequent water irrigation was caught in pre-weighed polystyrene dishes, stored at 37°C for 24 hours, and reweighed. Cutting ability was evaluated by the increase in dish weight from the collected debris. Data for both tests were analyzed using 1-way ANOVA and the SNK multiple comparisons testing at a significance level of P<0.05. The effect of pitch number was determined by comparing the Dentsply K-File to the Dentsply K-Reamer; the effect of cross-sectional area by the Dentsply Reamer to the SafeSiders.
Results:
Group | Flexibility (N*cm) |
| Cutting Ability (mg) | ||
| Mean | SNK |
| Mean | SNK |
SafeSiders | 1.57 ± 0.23 | A |
| 1.67 ± 0.12 | A |
Dentsply K-File | 1.93 ± 0.11 | B |
| 1.28 ± 0.34 | B |
Dentsply Reamer | 1.97 ± 0.16 | B |
| 1.27 ± 0.29 | B |
Conclusions: No statistically significant difference was found between the Dentsply K-File and Reamer for either flexibility or cutting ability, while SafeSiders was found to be significantly more flexibility and cut significantly more than the Dentsply K-File and Reamer. Cross-sectional area was observed to have an effect on flexibility and cutting ability.
Keywords: Elasticity, Endodontics and cutting ability
See more of: Dental Materials 10: Instruments and Equipment