Jannick De Tobel1,2,3,4, Griet Iona Loïs Parmentier5,6,7, Inès Phlypo8,9, Benedicte Descamps10, Sara Neyt11, Wim Leon Van De Velde12, Constantinus Politis7, Koenraad Luc Verstraete5, Patrick Werner Thevissen13. 1. Department of Radiology and Nuclear Medicine, Ghent University, Corneel Heymanslaan 10, 9000, Ghent, Belgium. jannick.detobel@ugent.be. 2. Department of Head, Neck and Maxillofacial Surgery, Ghent University Hospital, Ghent, Belgium. jannick.detobel@ugent.be. 3. Department of Oral and Maxillofacial Surgery, Leuven University Hospitals, Leuven, Belgium. jannick.detobel@ugent.be. 4. Department of Imaging and Pathology-Forensic Odontology, KU Leuven, Leuven, Belgium. jannick.detobel@ugent.be. 5. Department of Radiology and Nuclear Medicine, Ghent University, Corneel Heymanslaan 10, 9000, Ghent, Belgium. 6. Department of Head, Neck and Maxillofacial Surgery, Ghent University Hospital, Ghent, Belgium. 7. Department of Oral and Maxillofacial Surgery, Leuven University Hospitals, Leuven, Belgium. 8. Department of Dentistry-Special Care in Dentistry, PaeCoMeDiS, Ghent University, Ghent, Belgium. 9. Department of Dentistry-Community Dentistry and Oral Public Health, PaeCoMeDiS, Ghent University, Ghent, Belgium. 10. IbiTech-Medisip-Infinity lab, Ghent University, Ghent, Belgium. 11. MOLECUBES NV, Ghent, Belgium. 12. Department of Oral and Maxillofacial Surgery, General Hospital Saint-Lucas, Ghent, Belgium. 13. Department of Imaging and Pathology-Forensic Odontology, KU Leuven, Leuven, Belgium.
Abstract
PURPOSE: To compare the Ghent and Graz magnetic resonance imaging (MRI) protocols for third molars, focusing on the assessment of apical closure. To study the influence of (1) voxel size and (2) head fixation using a bite bar. To compare both protocols with a ground truth of apical development. MATERIALS AND METHODS: In 11 healthy volunteers, 3T MRI was conducted, including four Ghent sequences and two Graz sequences, with and without bite bar. After removal, 39 third molars were scanned with 7T μMRI and μCT to establish the ground truth of apical development. Three observers in consensus evaluated assessability and allocated developmental stages. RESULTS: The Ghent T2 FSE sequence (0.33 × 0.33 × 2 mm3) was more assessable than the Graz T1 3D FSE sequence (0.59 × 0.59 × 1 mm3). Comparing assessability in both sequences with bite bar rendered P = 0.02, whereas comparing those without bite bar rendered P < 0.001. Within the same sequence, the bite bar increased assessability, with P = 0.03 for the Ghent T2 FSE and P = 0.07 for the Graz T1 3D FSE. Considering μCT as ground truth for staging, allocated stages on MRI were most frequently equal or higher. Among in vivo protocols, the allocated stages did not differ significantly. CONCLUSION: Imaging modality-specific and MRI sequence-specific reference data are needed in age estimation. A higher in-plane resolution and a bite bar increase assessability of apical closure, whereas they do not affect stage allocation of assessable apices.
PURPOSE: To compare the Ghent and Graz magnetic resonance imaging (MRI) protocols for third molars, focusing on the assessment of apical closure. To study the influence of (1) voxel size and (2) head fixation using a bite bar. To compare both protocols with a ground truth of apical development. MATERIALS AND METHODS: In 11 healthy volunteers, 3T MRI was conducted, including four Ghent sequences and two Graz sequences, with and without bite bar. After removal, 39 third molars were scanned with 7T μMRI and μCT to establish the ground truth of apical development. Three observers in consensus evaluated assessability and allocated developmental stages. RESULTS: The Ghent T2 FSE sequence (0.33 × 0.33 × 2 mm3) was more assessable than the Graz T1 3D FSE sequence (0.59 × 0.59 × 1 mm3). Comparing assessability in both sequences with bite bar rendered P = 0.02, whereas comparing those without bite bar rendered P < 0.001. Within the same sequence, the bite bar increased assessability, with P = 0.03 for the Ghent T2 FSE and P = 0.07 for the Graz T1 3D FSE. Considering μCT as ground truth for staging, allocated stages on MRI were most frequently equal or higher. Among in vivo protocols, the allocated stages did not differ significantly. CONCLUSION: Imaging modality-specific and MRI sequence-specific reference data are needed in age estimation. A higher in-plane resolution and a bite bar increase assessability of apical closure, whereas they do not affect stage allocation of assessable apices.
Keywords:
Adolescent; Adult; Age determination by teeth; Magnetic resonance imaging; Third molar
Authors: Jannick De Tobel; Elke Hillewig; Michiel Bart de Haas; Bram Van Eeckhout; Steffen Fieuws; Patrick Werner Thevissen; Koenraad Luc Verstraete Journal: Eur Radiol Date: 2019-01-07 Impact factor: 5.315
Authors: M Hagen; S Schmidt; R Schulz; V Vieth; C Ottow; A Olze; H Pfeiffer; A Schmeling Journal: Int J Legal Med Date: 2020-01-02 Impact factor: 2.686