Browsing by Subject "Teeth"
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Item Assessing the Accuracy and Reliability of Root Crack and Fracture Detection in Teeth Using Sweep Imaging with Fourier Transform (SWIFT) Magnetic Resonance Imaging (MRI)(2017-08) Schuurmans, TylerIntroduction: Magnetic Resonance Imaging (MRI) has the potential to aid in determining the presence and extent of cracks/fractures in teeth due to more advantageous contrast, without ionizing radiation. An MRI technique called Sweep Imaging with Fourier Transform (SWIFT) has overcome many of the inherent difficulties of conventional MRI with detecting fast-relaxing signals from densely mineralized dental tissues. The objectives of this in vitro investigation were to develop MRI criteria for root crack/fracture identification in teeth and to establish intra- and inter-rater reliabilities and corresponding sensitivity and specificity values for the detection of tooth-root cracks/fractures in SWIFT MRI and limited field of view (FOV) CBCT. Materials and Methods: MRI-based criteria for crack/fracture appearance was developed by an MRI physicist and 6 dentists, including 3 endodontists and 1 Oral and Maxillofacial (OMF) radiologist. Twenty-nine human adult teeth previously extracted following clinical diagnosis by a board-certified endodontist of a root crack/fracture were frequency-matched to 29 non-cracked controls. Crack/fracture status confirmation was performed with magnified visual inspection, transillumination and vital staining. Samples were scanned with two 3D imaging modalities: 1) SWIFT MRI (10 teeth/scan) via a custom oral radiofrequency (RF) coil and a 90cm, 4-T magnet; 2) Limited FOV CBCT (1 tooth/scan) via a Carestream (CS) 9000 (Rochester, NY). Following a training period, a blinded 4-member panel (3 endodontists, 1 OMF radiologist) evaluated the images with a proportion randomly re-tested to establish intra-rater reliability. Overall observer agreement was measured using Cohen’s kappa and levels of agreement judged using the criteria of Landis and Koch. Sensitivity and specificity were computed with 95% confidence interval (CI); statistical significance was set at 0.05. Results: MRI-based crack/fracture criteria were defined as 1-2 sharply-delineated, high-signal (bright/white) line shape(s) that must be visible on multiple contiguous image slices. The line shape(s) must present as: single entities, or parallel pairs in close proximity, or pairs in close proximity exhibiting convergence or divergence extending from the external boundary of the tooth to the pulpal cavity. Intra-rater reliability for MRI was fair-to-almost perfect (κ=0.38-1.00) and for CBCT was moderate-to-almost perfect (κ=0.66-1.00). Inter-rater reliability for MRI was fair (κ=0.21; 95%CI:0.10-0.31; p< 0.001) and for CBCT was moderate (κ=0.45; 95%CI:0.34-0.56; p<0.001). Sensitivity: MRI=0.59 (95% CI:0.39-0.76; p=0.46); CBCT=0.59 (95% CI:0.59-0.76; p=0.46). Specificity: MRI=0.83 (95% CI:0.64-0.94; p<0.01); CBCT=0.90 (95% CI:0.73-0.98; p<0.01). Conclusions: Education and training for both imaging modalities is needed to improve reliabilities for the identification of tooth-root crack/fractures. Despite the advantages of increased contrast and absence of artifact from radio-dense materials in MRI, comparable measures of sensitivity and specificity (in relation to CBCT) suggest quality MRI improvements are needed, specifically in image acquisition and post-processing parameters. Given the early stage of technology development and multiple available pathways to optimize MR imaging of teeth, there may be a use for SWIFT MRI in detecting cracks and fractures in teeth.Item The morphology and evolution of tooth replacment in the combtooth blennies (Ovalentaria: Blenniidae)(2020-07) Williams, KeifferThis research investigates the morphology and evolution of tooth replacement in the combtooth blennies. Blennies exhibit complex dentition that is not easily categorized by previously established metrics of teleost tooth replacement (extraosseous and intraosseous replacement). Most blennies are heterodont, possessing a single row of comb-shaped feeding teeth on the anterior portion of their jaws, and enlarged canines on the posterior portion of their lower jaws used for agonistic interactions. However, this bizarre dentition has been intentionally overlooked in classic surveys of teleost dentition due to its complexity. In Chapter 1, I investigate how feeding teeth are replaced in salariin blennies by establishing a descriptive model of tooth replacement for the Pacific Leaping Blenny, Alticus arnoldorum. This fish exhibits tooth replacement and tooth attachment that defy the discrete categorizations used for most other teleost dentitions. Using my descriptive model, I then propose hypotheses of how feeding teeth function in this fish. In chapter 2, I investigate how modes of tooth replacement have evolved in blennies. I find that canines in blennies are consistently replaced intraosseously, while feeding teeth across the family vary from intraosseous to a derived form of extraosseous replacement. These results further support the concept of teleost tooth replacement as a continuum rather than discretely classified modes. My results also suggest teleost tooth replacement needs to be carefully examined within a phylogenetic context to better understand how trophic morphological novelties evolve, as modes of tooth replacement likely play a key role in ecological and functional morphological shifts in teleosts.Item The Relationship Between the Amount of Orthodontic Tooth Movement and the Effectiveness of Computer Assisted Treatment(2017-06) Czarnik, ScottAim: To evaluate the effectiveness of SureSmile technology and determine if a correlation exists between discrepancy and overall movement throughout treatment. Methods: Digital pre-treatment models, predicted final treatment models, and actual final treatment models of 30 patients were superimposed to determine both the overall movement each tooth completed throughout treatment, the amount of discrepancy between predicted and actual results, and if any correlation exists between these two findings. Results: Statistically significant correlation between amount of overall tooth movement and discrepancy between predicted and actual final alignment was found in the following instances: Mesial-distal dimension in maxillary canines. Facial-lingual dimension of maxillary central incisors, and lateral incisors. Torque of maxillary central incisors, lateral incisors, 1st molars, and all mandibular teeth. Rotation of maxillary central incisors. Conclusion: The effectiveness of SureSmile is highly variable and dependent on tooth type and dimension of movement.