INTRODUCTION

Early detection of vertical root fracture (VRF) is important for clinical endodontic practice. The purpose of this study was to measure the fracture width (distance between 2 sides of the fracture) of VRF teeth in vitro by using 2 micro-computed tomography (μ-CT) systems with different spatial resolution and voxel size.

METHODS

Thirty-seven endodontically treated teeth with VRF were scanned by 80-μm pixel size μ-CT. Fifteen teeth with no obvious fracture line, blurred image, or fracture space less than 100 μm were scanned by 9-μm pixel size μ-CT.

RESULTS

Presence of 2 VRF lines was more common in premolars (82%) than in molars (53%). In 7 premolars (32%) and 9 molars (60%), the VRF lines extended to within the apical 3 mm of the root. All fracture lines were detected by 9-μm pixel size μ-CT, but only 22 of 37 VRF teeth had vertical fracture identified by 80-μm μ-CT. From μ-CT examination, none of the fracture lines showed consistent and uniform fracture space. If 2 fracture lines were present, they were typically in opposite (not linear) directions. There was a significant correlation between 2 fracture lines or fracture lines extending within the 3 mm of the apex and fracture width greater than 100 μm.

CONCLUSIONS

Application of 9-μm μ-CT can be accurately used for early detection of VRF. Fracture characteristics (eg, number of fracture lines, extension of fracture line) may affect the fracture width. Appropriate use of μ-CT technology can be helpful for early diagnosis of VRF.