IADR Abstract Archives
Evaluation of Calcium Hydroxide Pastes in Exposed Vital Nerve Tissue.
Objectives: Calcium hydroxide (CH) preparations are used in many endodontic procedures. Extrusion of CH into the mandibular canal may cause inferior alveolar nerve (IAN) injury. Using an in-vivo rat sciatic nerve sample, this phenomenon was subsequently imaged using multiple modalities. To determine if morphological differences were evident using micro-computed tomography (uCT), and scanning electron microscopy (SEM) in control and test nerve sections
Methods: 14 sciatic nerve samples were harvested from 7 laboratory rats after CH paste was placed in-vivo for a set amount of time. Control was taken on the same nerve more dorsal than the test site. Specimens were scanned with a uCT (SkyScan1272, Bruker, Kontich/Belgium) at 2.5um, 1200ms, rotation step of 0.2, frame of 3, and random movement of 30. Samples were observed under a SEM (FEG 250, ThermoFisher,USA) at 200x,400x,800x,1000x and 1500x of magnification under the low vacuum Secondary Electron detector (LFD). Images will be interpreted to determine if differences are present in the CH samples compared to the controls.
Results: The nerve sections obtained from the control group demonstrated normal morphologic characteristics. For the CH paste group, varying degrees of axonal and myelin degeneration and loss of cellular outline were observed at 30 minutes, 60 minutes, 90 minutes, and 120 minutes of exposure. In addition, the animal model protocol appears hopeful for testing CH and other substances on nerve tissue in-vivo.
Conclusions: Morphologic differences were observed between the CH paste group when compared with the control at different time points. uCT and SEM imaging are effective tools in evaluating nerve structure.
Methods: 14 sciatic nerve samples were harvested from 7 laboratory rats after CH paste was placed in-vivo for a set amount of time. Control was taken on the same nerve more dorsal than the test site. Specimens were scanned with a uCT (SkyScan1272, Bruker, Kontich/Belgium) at 2.5um, 1200ms, rotation step of 0.2, frame of 3, and random movement of 30. Samples were observed under a SEM (FEG 250, ThermoFisher,USA) at 200x,400x,800x,1000x and 1500x of magnification under the low vacuum Secondary Electron detector (LFD). Images will be interpreted to determine if differences are present in the CH samples compared to the controls.
Results: The nerve sections obtained from the control group demonstrated normal morphologic characteristics. For the CH paste group, varying degrees of axonal and myelin degeneration and loss of cellular outline were observed at 30 minutes, 60 minutes, 90 minutes, and 120 minutes of exposure. In addition, the animal model protocol appears hopeful for testing CH and other substances on nerve tissue in-vivo.
Conclusions: Morphologic differences were observed between the CH paste group when compared with the control at different time points. uCT and SEM imaging are effective tools in evaluating nerve structure.