Browsing by Subject "Diagnosis"
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Item Mri Detection Of Vertical Root Fractures In Endodontically Treated Teeth(2020-08) Groenke, BethINTRODUCTION: Vertical root fracture (VRF) is known to occur in root canal treated (RCT) teeth and results in tooth loss. VRFs are difficult to diagnose. Magnetic Resonance Imaging (MRI) has the potential to identify VRF due to beneficial partial volume averaging, without using ionizing radiation. This investigation aims to compare the sensitivity and specificity of MRI versus cone-beam computed tomography (CBCT) in detecting VRF, using micro-computed tomography (microCT) as the reference standard. It also will describe the limits of MRI for detecting VRF. METHODS: 115 extracted human tooth roots were RCT using common techniques. VRFs were induced in a proportion that resulted in 62 VRF samples and 53 non-fractured control samples. All samples were imaged in a phantom using MRI and CBCT. Axial images for MRI and CBCT were presented to three board-certified endodontists. Evaluators determined VRF status and a confidence assessment for that decision. 30% of images were resampled to calculate intra- and inter-rater reliability. For MRI, the most coronal slice with discernible VRF was measured on correlated microCT to determine the minimum VRF width (µm). RESULTS: Sensitivity for MRI and CBCT were 0.66 (95%CI:0.53-0.78) and 0.58 (95%CI:0.45-0.70). Specificity was 0.72 (95%CI:0.58-0.83) and 0.87 (95%CI:0.75-0.95). Intra-rater reliability ranged from k=0.29-0.48 for MRI and k=0.30-0.44 for CBCT. Inter-rater reliability for MRI was k=0.37 and CBCT k=0.49. Median VRF width detected using MRI was 39µm (first quartile:20µm, third quartile: 58µm). CONCLUSION: MRI demonstrated ability to repeatedly detect VRF as small as 20 µm. There was no significant difference between sensitivity nor specificity for MRI versus CBCT in detecting VRF, despite the early stage of MRI development.Item Optimal head position: A new frame of reference for cephalometric analysis(2013-08) Teeters, Christopher AndrewIntroduction: Facial considerations are important in any contemporary cephalometric analysis based on a soft-tissue paradigm, and head position is often an important component of these soft-tissue measurements. Natural head position (NHP) has long been used as the reference position for craniofacial morphology and it has been subject to great scrutiny due to its inherent variability. This study aims to determine if there is an operator-defined optimal head position (OHP) that is deemed the most pleasant, universal to all skeletal classifications, and parallel to Frankfort Horizontal (FH). Methods: 31 subjects (10 orthodontists, 10 orthodontic residents, and 11 orthodontic staff members) were asked to take an online survey evaluating 9 soft-tissue rendering profile positions (2.5 degrees apart) of 30 different models (N=31, Power = 0.92). They were asked to indicate the most pleasant profile orientation and to disclose whether they were orthodontists, residents, or staff members. Results: Chi-square tests and two one-sided t-test procedure (TOST) tests were performed to test the null hypotheses. All null hypotheses were rejected, therefore: (1) not all profile orientations were chosen with equal frequency. The most commonly chosen angle was 0 (about 30% of the choices, p < 0.0001) corresponding to the Helion-Canthion line (HC line) parallel to the floor and about 70% of the choices were within 2.5 degrees of the angle 0. There was no significant difference in the head orientations chosen by orthodontists, orthodontic residents, and staff members; (2) the three skeletal classes demonstrated a very similar pattern of angle choice, which was most often 0 (p < 0.05); and (3) the soft-tissue HC line and hard-tissue FH deviation resulted in a mean of deviation range of values within the limits of ±0.5° (p< 0.001) denoting very high concordance between HC line and FH. Conclusions: 70% of responders chose the orientation within one standard deviation consistent with HC parallel to the floor (p < 0.001). We noticed that the most commonly chosen angle was 0 for each of the three skeletal groups (p < 0.05), and that their frequency distributions of angle choice had very similar shapes. The suggested OHP reference plane proved to be parallel to FH and it was deemed to be an esthetically pleasing and easily determined soft-tissue head orientation. We believe that OHP can be confidently and meaningfully used in contemporary cephalometric analyses. This head orientation may be obtained prior to taking pictures and radiographs (including CBCTs) or after the exposure, by rotating the picture or soft tissue rendering until the HC line is parallel to the floor.Item The Oswestry Disability Index and back pain(2012-07-24) Germscheid, Jonathan