MICROCOMPUTED TOMOGRAPHY OF CALCIUM-HYDROXIDE EXPOSED VITAL NERVE TISSUE: A PILOT PROTOCOL

Abstract

<h3>Background</h3> Calcium hydroxide (CH) preparations are used in many endodontic procedures. Extrusion of CH into the mandibular canal may cause inferior alveolar nerve (IAN) injury. With an in vivo rat sciatic nerve sample, this phenomenon was subsequently imaged by using multiple modalities. <h3>Objective</h3> The aim of this study was to determine if histologic differences were evident on microcomputed tomography (MCT), scanning electron microscopy (SEM) and hematoxylin and eosin (H&E)–stained light microscopy in control and test nerve sections. <h3>Materials and Methods</h3> Fourteen sciatic nerve samples were harvested from 7 laboratory rats after CH paste was placed in vivo for a set amount of time. A control was taken on the same nerve more dorsal than the test site. Specimens were scanned on an MCT unit (SkyScan1272, Bruker, Kontich, Belgium) at 2.5 µm, 1200 ms, rotation step of 0.2, frame of 3, and random movement of 30. Samples were observed under a scanning electron microscope (FEG 250; ThermoFisher, Waltham, MA) at ×200, ×400, ×800, ×1000, and ×1500 magnifications under the low-vacuum secondary electron detector (LFD). Images were interpreted to determine if differences were present in the CH samples compared with the controls. <h3>Results</h3> Preliminary findings showed promise for demonstrating nerve structure and form. In addition, the animal model protocol appears helpful for testing CH and other substances on nerve tissue in vivo. <h3>Discussion</h3> MCT and SEM imaging are effective tools in evaluating nerve structure and change in conjunction with H&E–stained histologic samples. <h3>Acknowledgments</h3> We would like to thank John Chrisler and John Hough for their assistance with surgical and specimen preparations during this project.