Radiology Commons^™

Influence Of Stainless Steel Orthodontic Brackets On Magnetic Resonance Imaging, Christian James Hoybjerg

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Magnetic resonance imaging (MRI) machines provide 2D as well as 3D images that are excellent in contrasting soft-tissue in the maxillofacial region and are void of ionizing radiation. The drawbacks include the lack of depiction of cortical bony detail and image degradation caused by substances in the scanned area. Specifically, in the orthodontic field stainless steel brackets cause more distortion of MR images then any other bracket material. It is unknown what type of stainless steel alloy causes the most MRI distortion. The purpose of this study is to evaluate the degree of craniofacial MR distortion caused by various …

Observer Reliability Of Cephalometric Landmark Identification On 3-D Mr Images, Michael S. Pollack

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Cephalometric analysis is a cornerstone of orthodontic diagnosis, yet much information is lost when 3-dimensional structures are assessed with 2-dimensional methods. CBCT offers 3-dimensional imaging but at the cost of higher levels of ionizing radiation. Magnetic resonance imaging provides 3-dimensional imaging without ionizing radiation and additionally imparts visualization of soft tissue structures. Prior to employing MR images for cephalometric analysis, reliability of landmark identification must be assessed. The purpose of this study was to evaluate intra- and interobserver reliability in 3-dimensional landmark identification using MR images.

Materials and Methods: Fifteen cranial MR images (3.0 T, MP-RAGE) from subjects between …

Effects Of Functional Appliances On The Tmj And Mandibular Length Of Skeletal Class Ii Patients: A Cone Beam Computed Tomography Study, David C. Lee

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Functional appliances have been efficiently used in the treatment of Class II malocclusions caused by retrognathic mandibles. Cone beam computed tomography has enabled us to make more accurate linear measurements by eliminating superimposition of other structures and to analyze skeletal anatomic detail in all three planes of space. This retrospective study evaluated the osseous changes in the temporomandibular joint (TMJ) and length of the mandible in skeletal Class II malocclusion patients treated with the fixed functional appliances and compared measurements with Class I malocclusion patients treated with orthodontic mechanics that did not alter skeletal relationships.

Materials and Methods: Twelve …