title: Role of MRI for detecting micro cracks in teeth.
abstract: OBJECTIVE
  To evaluate the limit of tooth crack width visualization by two MRI pulse sequences in comparison with CBCT.
  
  
  METHODS
  Two extracted human teeth with known crack locations and dimensions, as determined by reference standard microCT, were selected for experimental imaging. Crack location/dimension and the presence of common dental restorative materials such as amalgam were typical of that found clinically. Experimental imaging consisted of conventional CBCT scans and MRI scans with two pulse sequences including Sweep Imaging with Fourier Transformation (SWIFT) and gradient echo (GRE). CBCT and MR images of extracted teeth were acquired using acquisition parameters identical to those used for in vivo imaging. Experimental and reference standard images were registered and the limit of tooth crack visualization was determined.
  
  
  RESULTS
  Collected images indicate that SWIFT could demonstrate cracks with 20-µm width, which is 10 times narrower than the imaging voxel size. Cracks of this size were not visible in GRE images, even with a short echo time of 2.75 ms. The CBCT images were distorted by artefacts owing to close location of metallic restorations.
  
  
  CONCLUSIONS
  The successful visualization of cracks with the SWIFT MRI sequence compared with other clinical modalities suggests that SWIFT MRI can effectively detect microcracks in teeth and therefore may have potential to be a non-invasive method for the in vivo detection of cracks in human teeth.
authors.affiliation: 1 Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Djaudat
authors.initials: D
authors.lastname: Idiyatullin
authors.affiliation: 1 Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Garwood
authors.affiliation: 2 Department of Diagnostic and Biological Sciences, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Laurence
authors.initials: L
authors.lastname: Gaalaas
authors.affiliation: 3 Division of TMD and Orofacial Pain and Department of Neurology, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Donald R
authors.initials: DR
authors.lastname: Nixdorf
mesh_terms: D016477:Artifacts; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003387:Cracked Tooth Syndrome / Q000000981:diagnostic imaging*; D003723:Dental Amalgam; D005240:Feasibility Studies; D005583:Fourier Analysis; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D055114:X-Ray Microtomography / Q000379:methods
chemical_list: D003723:Dental Amalgam
keywords: CBCT; MRI; dentistry; diagnostic imaging; tooth fractures