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Start Over Author "Abdullah, Saleem" Publisher springer science and business media llc
62 results on '"Abdullah, Saleem"'

2. Diagnostic compatibility of various fixed orthodontic retainers for head/neck MRI and dental MRI

Author

Alexander Juerchott, Christoph J. Roser, Muhammad Abdullah Saleem, Mathias Nittka, Christopher J. Lux, Sabine Heiland, Martin Bendszus, and Tim Hilgenfeld

Subjects
General Dentistry
Abstract

Objectives To evaluate the diagnostic MRI compatibility of different fixed orthodontic retainers using a high-resolution 3D-sequence optimized for artifact reduction. Materials and methods Maxillary and mandibular retainers made of five different materials were scanned in vitro and in vivo at 3 T MRI using an MSVAT-SPACE sequence. In vitro, artifact volumes were determined for all maxillary and mandibular retainers (AVmax; AVmand). In vivo, two independent observers quantified the extent of artifacts based on the visibility of 124 dental and non-dental landmarks using a five-point rating scale (1 = excellent, 2 = good, 3 = acceptable, 4 = poor, 5 = not visible). Results Rectangular-steel retainers caused the largest artifacts (AVmax/AVmand: 18,060/15,879 mm3) and considerable diagnostic impairment in vivo (mean landmark visibility score ± SD inside/outside the retainer areas: 4.8 ± 0.8/2.9 ± 1.6). Smaller, but diagnostically relevant artifacts were observed for twistflex steel retainers (437/6317 mm3, 3.1 ± 1.7/1.3 ± 0.7). All retainers made of precious-alloy materials produced only very small artifact volumes (titanium grade 1: 70/46 mm3, titanium grade 5: 47/35 mm3, gold: 23/21 mm3) without any impact on image quality in vivo (each retainer: visibility scores of 1.0 ± 0.0 for all landmarks inside and outside the retainer areas). Conclusions In contrast to steel retainers, titanium and gold retainers are fully compatible for both head/neck and dental MRI when using MSVAT-SPACE. Clinical relevance This study demonstrates that titanium and gold retainers do not impair the diagnostic quality of head/neck and dental MRI when applying an appropriate artifact-reduction technique. Steel retainers, however, are not suitable for dental MRI and can severely impair image quality in head/neck MRI of the oral cavity.

Published
2023

7. In vivo assessment of artefacts in MRI images caused by conventional twistflex and various fixed orthodontic CAD/CAM retainers

Author

Christoph J. Roser, Tim Hilgenfeld, Muhammad Abdullah Saleem, Thomas Rückschloß, Sabine Heiland, Martin Bendszus, Christopher J. Lux, and Alexander Juerchott

Subjects
Orthodontics, Oral Surgery
Abstract

Purpose To assess magnetic resonance imaging (MRI) artefacts caused by different computer-aided design/computer-aided manufacturing (CAD/CAM) retainers in comparison with conventional hand bent stainless steel twistflex retainers in vivo. Materials and methods MRI scans (3 Tesla) were performed on a male volunteer with different CAD/CAM retainers (cobalt–chromium, CoCr; nickel–titanium, NiTi; grade 5 titanium, Ti5) and twistflex retainers inserted. A total of 126 landmarks inside and outside the retainer area (RA; from canine to canine) were evaluated by two blinded radiologists using an established five-point visibility scoring (1: excellent, 2: good, 3: moderate, 4: poor, 5: not visible). Friedman and two-tailed Wilcoxon tests were used for statistical analysis (significance level: p Results Twistflex retainers had the strongest impact on the visibility of all landmarks inside (4.0 ± 1.5) and outside the RA (1.7 ± 1.2). In contrast, artefacts caused by CAD/CAM retainers were limited to the dental area inside the RA (CoCr: 2.2 ± 1.2) or did not impair MRI-based diagnostics in a clinically relevant way (NiTi: 1.0 ± 0.1; Ti5: 1.4 ± 0.6). Conclusion The present study on a single test person demonstrates that conventional stainless steel twistflex retainers can severely impair the diagnostic value in head/neck and dental MRI. By contrast, CoCr CAD/CAM retainers can cause artefacts which only slightly impair dental MRI but not head/neck MRI, whereas NiTi and Ti5 CAD/CAM might be fully compatible with both head/neck and dental MRI.

Published
2023

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