Purpose: to evaluate resected root-end surfaces of bilaterally matched human teeth for cracks before and after ultrasonic root-end preparation.
N= 40 bilaterally matched single rooted teeth.
o All teeth were initially examined for the presence of root surface cracks using 20× magnification
oG1: teeth uninstrumented. G2: accessed, instrumentation (Crown-down, step-back) & obturated by lateral condensation
oA 3-mm root-end resection was done in both groups using a low-speed diamond blade & stored in methylene blue.
oAfter 48hs, root-ends evaluated by 2 independent investigators with a stereomicroscope & a fiberoptic transillumination.
oAll teeth then received a root-end preparation using the ultrasonic unit & were then re-evaluated using same method.
Most highlighted Results:
oThere were no significant differences when gutta-percha filled roots were compared to uninstrumented roots with regard to the number or type of cracks after root-end resection or root-end preparation.
oThere were no significant differences in the number or type of cracks following root resection and ultrasonic root-end preparation when compared to teeth with root resection alone.
oFollowing resection of the forty roots, ten cracks were observed on six root-ends
oFollowing root-end preparation, there were 13 cracks present on eight of the forty root-ends
•Even though the presence of cracks was not significant in instrumented & obturated root canals or in roots with retro-prep with ultrasonics, staining with methylene blue dye is an important step.