[Experimental study of preparation errors during instrumentation of artificial curved root canals with stainless steel K files].
OBJECTIVE
To investigate the features and rules of preparation errors developed from instrumentation of curved root canals.


METHODS
8 curved artificial root canals were prepared with stainless steel K files by the step-back technique,the root canals were digitally photographed,the images were analysed by the software Image-Pro Plus,the shapes and positions of the root canals were measured and analysed.SPSS 10.0 software package was used for statistical analysis, paired-samples t test was used to compare the difference of the means among sample groups.


RESULTS
After root canal preparation,the mean value of the angles of canal curvature decreased from 36.21 degrees to 21.98 degrees , while the mean value of the radius of the canal curvature increased from 6.25mm to 11.35mm; the canal axes transported and intercrossed with the original axes at 2 points and created 3 intersection zones.The taper of the root canals was destroyed and a series of instrumentation defaults were created.


CONCLUSIONS
The cause of preparation errors was the transportation of the root canal instruments leaded by the elastic force and cutting effects.
Zhou
Pei-gang
PG
Department of Stomatology, First People's Hospital of Wujiang, Wujiang 215200, Jiangsu Province, China.
Gu
Yong-chun
YC
Ding
Yue-feng
YF
D003722:Dental Alloys; D003762:Dental Instruments; D003786:Dental Pulp Cavity; D006801:Humans; D009532:Nickel; D018915:Root Canal Preparation; D012390:Root Canal Therapy; D013193:Stainless Steel; D014025:Titanium
D003722:Dental Alloys; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium