To compare the initial penetration depth of fine-fine nickel-titanium (NiTi) and fine-fine stainless-steel (SS) spreaders during lateral compaction of .02 or .04 tapered master gutta-percha cones and to evaluate the effect of increasing canal curvature on penetration depth.
-N= 51 root canals -coronal half of the crown for each tooth was removed, Access, WL using #10 K-file.
-Standardized canal preparation: crown-down continuous taper instrumentation (Profile .04 taper, sizes 20-40).
-2.6% sodium hypochlorite irrigation, orifices enlarged with a #5 Gates Glidden.
-Buccolingual and mesiodistal RGs scanned, and images were digitized, the curvatures of canals were measured according to Schneider.
-The apparatus was placed on an analytical scale to measure the force used during spreader placement. (Fig.)
-The apical 5 mm of each gutta-percha cone was coated with ZOE sealer
-Apical force of 1.5 kg ( 0.05 kg), with no rotational force, was applied to place the spreaders.
-FF, 25 mm NiTi, and FF, 25 mm SS finger spreaders were used with size 40/.04 and size 40/.02 GP cones.
-(a) NiTi spreader with size 40/.02 taper master cone
-(b) NiTi spreader with 40/.04 taper master cone
-(c) SS spreader with 40/.02 taper master cone
-(d) SS spreader with 40/.04 taper master cone.
– For each group, the depth of spreader penetration was recorded three times using a new master cone for each measurement and averaged for analysis.
-Canals were then divided by their degree of curvature into two subgroups 0–20 degrees, and > 20 degrees).
•Most highlighted Results:
Table and figure
- The mean depths of spreader penetration= distance from working length
– The depth of penetration for both NiTi and SS spreaders was significantly less when using .04 Vs. .02 master cones.
– The mean difference in depth of spreader penetration between .04 and .02 tapered cones was 2.93 mm for NiTi spreaders and 3.17 mm for SS spreaders.
– Both NiTi and SS spreaders penetrated to a significantly greater depth in canals with curvatures > 20 degrees compared with canals with curvatures of 0-20 degrees using both .02 and .04 tapered master cones