ABSTRACT
Objective:To evaluate the effects of different ultrasonic retroprep tips on the root-end preparation in cadavers.Methods:34 anterior teeth in situ in maxillary and mandibular jaws in cadavers were chosen and the root-end of 3 mm of all teeth was exposed. Root canal was prepared and filled with gutta-purcha in all teeth,3 mm of the root end was cut off.The teeth were divided into 2 treat-ment groups(n=1 5),and 1 control group(n=4).The root-end preparation was made using ultrasonic diamond tip and stainless steel tip respectively to 3 mm depth.The teeth in control group were not treated.Microcracks,marginal integrity and gutta-percha clearance were observated under SEM.Results:Diamond ultrasonic tips provoked a smaller number of cracks(P=0.059)and destroy of margin-al integrity(P=0.269)than stainless steel tips.Less gutta-percha clearance was produced by stainless steel tip than that by diamond ultrasonic tip(P=0.006).Conclusion:Diamond ultrasonic tip is more suitable for root-end preparation.