Document Type : Original Article


1 Graduated from General Dentistry, Zahedan University of Medical Sciences, Zahedan, Iran

2 Medical student, Taras Shevchenko National university of Kyiv


Introduction & Aim: The problem of crack formation during apical cavity preparation is one of the current challenges of endodontic problems. The purpose of this study was to investigate in vitro evaluation of effect of supporting bone on preventing cracks in roots resected by ultrasonic and bur.

Materials and Methods: In this experimental study, 113 single-rooted human teeth with single canal and direct root were examined in the control group (40 teeth) and the experimental group (73 teeth). To evaluate the number of canals and the curvature of the root, P.A digital radiographs were prepared from buccolingual and mesiodistal directions. All teeth were evaluated for surgical microscopy in terms of crack, external analysis, and any defect. In all samples, the apical cavity was provided with diamond burs and a spray of air and then irrigated with sodium hypochlorite. In the control and experimental group, the samples were divided into two groups with of supporting bone and no of supporting bone. Each group was again divided into two subgroups (A, B). Then from the 3 mm apical portion of the roots, it was cut off by bur (subgroup A) and ultrasonic (subgroup B). The cut surface was examined by endoscopy microscope for presence or absence of crack.

Results: All samples with supporting bone in both groups were free from cracks by ultrasonic and bur. In endodontic roots, without supporting bone, 92.86% in bur method and 90% in the ultrasonic technique, lacked cracks. In the control group, without bone support, 20% in the bur method and all the samples in the ultrasonically free of cracks.

Conclusion: Supporting bone prevents cracking in endodontic roots by ultrasonic and bur.


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