International Journal of Legal Medicine

, Volume 133, Issue 2, pp 583–592 | Cite as

Magnetic resonance imaging of third molars in forensic age estimation: comparison of the Ghent and Graz protocols focusing on apical closure

  • Jannick De TobelEmail author
  • Griet Iona Loïs Parmentier
  • Inès Phlypo
  • Benedicte Descamps
  • Sara Neyt
  • Wim Leon Van De Velde
  • Constantinus Politis
  • Koenraad Luc Verstraete
  • Patrick Werner Thevissen
Original Article



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.


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.


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.


Age determination by teeth Third molar Adolescent Adult Magnetic resonance imaging 



Intra-class correlation coefficient


Micro computed tomography


Micro magnetic resonance imaging


Constructive interference in steady state


Fast spin echo


Multiplanar reconstruction


Specific absorption rate


Zero echo time



We are very grateful to all participants and everybody who helped with recruitment. We wish to express our most sincere gratitude and appreciation to Martin Urschler for making the exact parameters of the Graz protocol available for our research and for his critical appraisal of the manuscript. We also want to thank Dominique Neyts for her critical review of the manuscript. Lastly, we gratefully acknowledge the contribution of Geert Dermout and Louis Simoen in the production of the figures.


This study has received funding by the American Society of Forensic Odontology (ASFO) in form of its Research Grant 2017.

Compliance with ethical standards

This project was approved by the Ghent University Hospital Ethics Committee.Written informed consent was obtained from all volunteers, and in case of minors, from their parents.

Conflict of interest

Sara Neyt declares a relationship with the following company: MOLECUBES NV (Gent, Belgium). The μCT scans for the current study were performed free of charge by this company.

The other authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.

Supplementary material

414_2018_1905_MOESM1_ESM.docx (395 kb)
ESM 1 (DOCX 394 kb)


  1. 1.
    Schmeling A, Grundmann C, Fuhrmann A, Kaatsch HJ, Knell B, Ramsthaler F, Reisinger W, Riepert T, Ritz-Timme S, Rösing FW, Rötzscher K, Geserick G (2008) Criteria for age estimation in living individuals. Int J Legal Med 122:457–460. CrossRefGoogle Scholar
  2. 2.
    Schmeling A, Dettmeyer R, Rudolf E, Vieth V, Geserick G (2016) Forensic age estimation. Dtsch Arztebl Int 113:44–50. Google Scholar
  3. 3.
    Schmeling A, Geserick G, Reisinger W, Olze A (2007) Age estimation. Forensic Sci Int 165:178–181CrossRefGoogle Scholar
  4. 4.
    Thevissen PW, Fieuws S, Willems G (2010) Human dental age estimation using third molar developmental stages: does a Bayesian approach outperform regression models to discriminate between juveniles and adults? Int J Legal Med 124:35–42. CrossRefGoogle Scholar
  5. 5.
    Hillewig E, Degroote J, Van der Paelt T et al (2013) Magnetic resonance imaging of the sternal extremity of the clavicle in forensic age estimation: towards more sound age estimates. Int J Legal Med 127:677–689. CrossRefGoogle Scholar
  6. 6.
    Gelbrich B, Frerking C, Weiss S et al (2015) Combining wrist age and third molars in forensic age estimation: how to calculate the joint age estimate and its error rate in age diagnostics. Ann Hum Biol 42:389–396. CrossRefGoogle Scholar
  7. 7.
    Fieuws S, Willems G, Larsen-Tangmose S, Lynnerup N, Boldsen J, Thevissen P (2016) Obtaining appropriate interval estimates for age when multiple indicators are used: evaluation of an ad-hoc procedure. Int J Legal Med 130:489–499. CrossRefGoogle Scholar
  8. 8.
    Pinchi V, De Luca F, Focardi M et al (2016) Combining dental and skeletal evidence in age classification: pilot study in a sample of Italian sub-adults. Legal Med 20:75–79. CrossRefGoogle Scholar
  9. 9.
    Štern D, Kainz P, Payer C, Urschler M (2017) Multi-factorial age estimation from skeletal and dental MRI volumes. In: International Workshop on Machine Learning in Medical Imaging. Springer Quebec City, Canada, pp 61–69Google Scholar
  10. 10.
    Thevissen PW, Kvaal SI, Dierickx K, Willems G (2012) Ethics in age estimation of unaccompanied minors. J Forensic Odontostomatol 30(Suppl 1):84–102Google Scholar
  11. 11.
    Lockemann U, Fuhrmann A, Püschel K, Schmeling A, Geserick G (2004) Arbeitsgemeinschaft für Forensische Altersdiagnostik der Deutschen Gesellschaft für Rechtsmedizin. Rechtsmedizin 14:123–126. CrossRefGoogle Scholar
  12. 12.
    Gustafson G, Koch G (1974) Age estimation up to 16 years of age based on dental development. Odontol Revy 25:297–306Google Scholar
  13. 13.
    Gaudino C, Cosgarea R, Heiland S et al (2011) MR-imaging of teeth and periodontal apparatus: an experimental study comparing high-resolution MRI with MDCT and CBCT. Eur Radiol 21:2575–2583. CrossRefGoogle Scholar
  14. 14.
    Flugge T, Hovener JB, Ludwig U et al (2016) Magnetic resonance imaging of intraoral hard and soft tissues using an intraoral coil and FLASH sequences. Eur Radiol 26:4616–4623. CrossRefGoogle Scholar
  15. 15.
    Baumann P, Widek T, Merkens H et al (2015) Dental age estimation of living persons: comparison of MRI with OPG. Forensic Sci Int 253:76–80. CrossRefGoogle Scholar
  16. 16.
    Guo Y, Olze A, Ottow C, Schmidt S, Schulz R, Heindel W, Pfeiffer H, Vieth V, Schmeling A (2015) Dental age estimation in living individuals using 3.0 T MRI of lower third molars. Int J Legal Med 129:1265–1270. CrossRefGoogle Scholar
  17. 17.
    De Tobel J, Hillewig E, Bogaert S, Deblaere K, Verstraete K (2017) Magnetic resonance imaging of third molars: developing a protocol suitable for forensic age estimation. Ann Hum Biol 44:130–139. CrossRefGoogle Scholar
  18. 18.
    De Tobel J, Hillewig E, Verstraete K (2017) Forensic age estimation based on magnetic resonance imaging of third molars: converting 2D staging into 3D staging. Ann Hum Biol 44:121–129. CrossRefGoogle Scholar
  19. 19.
    De Tobel J, Phlypo I, Fieuws S, Politis C, Verstraete K, Thevissen P (2017) Forensic age estimation based on development of third molars: a staging technique for magnetic resonance imaging. J Forensic Odontostomatol 35:117–140Google Scholar
  20. 20.
    Levesque GY, Demirijian A, Tanguay R (1981) Sexual dimorphism in the development, emergence, and agenesis of the mandibular third molar. J Dent Res 60:1735–1741CrossRefGoogle Scholar
  21. 21.
    Weiger M, Pruessmann KP, Bracher AK, Köhler S, Lehmann V, Wolfram U, Hennel F, Rasche V (2012) High-resolution ZTE imaging of human teeth. NMR Biomed 25:1144–1151. CrossRefGoogle Scholar
  22. 22.
    Hovener JB, Zwick S, Leupold J et al (2012) Dental MRI: imaging of soft and solid components without ionizing radiation. J Magnetic Resonance imaging : JMRI 36:841–846. CrossRefGoogle Scholar
  23. 23.
    Levesque GY, Demirjian A (1980) The inter-examiner variation in rating dental formation from radiographs. J Dent Res 59:1123–1126CrossRefGoogle Scholar
  24. 24.
    Unterpirker W, Ebner T, Stern D, Urschler M. (2015) Automatic third molar localization from 3D MRI using random regression forests. In: Proceedings of the 19th Conference on Medical Image Understanding and Analysis (MIUA) Lincoln, United Kingdom. pp. 195–200Google Scholar
  25. 25.
    Liversidge HM (2008) Timing of human mandibular third molar formation. Ann Hum Biol 35:294–321. CrossRefGoogle Scholar
  26. 26.
    George J, Nagendran J, Azmi K (2012) Comparison study of growth plate fusion using MRI versus plain radiographs as used in age determination for exclusion of overaged football players. Br J Sports Med 46:273–278. CrossRefGoogle Scholar
  27. 27.
    Hillewig E, De Tobel J, Cuche O, Vandemaele P, Piette M, Verstraete K (2011) Magnetic resonance imaging of the medial extremity of the clavicle in forensic bone age determination: a new four-minute approach. Eur Radiol 21:757–767. CrossRefGoogle Scholar
  28. 28.
    Tangmose S, Jensen KE, Lynnerup N (2013) Comparative study on developmental stages of the clavicle by postmortem MRI and CT imaging. J Forensic Radiol Imaging 1:102–106. CrossRefGoogle Scholar
  29. 29.
    Urschler M, Krauskopf A, Widek T, Sorantin E, Ehammer T, Borkenstein M, Yen K, Scheurer E (2016) Applicability of Greulich-Pyle and Tanner-Whitehouse grading methods to MRI when assessing hand bone age in forensic age estimation: a pilot study. Forensic Sci Int 266:281–288. CrossRefGoogle Scholar
  30. 30.
    Nasel C, Gahleitner A, Breitenseher M, Czerny C, Solar P, Imhof H (1998) Dental MR tomography of the mandible. J Comput Assist Tomogr 22:498–502CrossRefGoogle Scholar
  31. 31.
    Gourtsoyiannis NC. (2011) Clinical MRI of the abdomen: why, how, when. Springer Science & Business Media, Berlin.
  32. 32.
    Saloner D (1995) The AAPM/RSNA physics tutorial for residents. An introduction to MR angiography. Radiographics 15:453–465. CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Jannick De Tobel
    • 1
    • 2
    • 3
    • 4
    Email author
  • Griet Iona Loïs Parmentier
    • 1
    • 2
    • 3
  • Inès Phlypo
    • 5
    • 6
  • Benedicte Descamps
    • 7
  • Sara Neyt
    • 8
  • Wim Leon Van De Velde
    • 9
  • Constantinus Politis
    • 3
  • Koenraad Luc Verstraete
    • 1
  • Patrick Werner Thevissen
    • 4
  1. 1.Department of Radiology and Nuclear MedicineGhent UniversityGhentBelgium
  2. 2.Department of Head, Neck and Maxillofacial SurgeryGhent University HospitalGhentBelgium
  3. 3.Department of Oral and Maxillofacial SurgeryLeuven University HospitalsLeuvenBelgium
  4. 4.Department of Imaging and Pathology—Forensic OdontologyKU LeuvenLeuvenBelgium
  5. 5.Department of Dentistry—Special Care in Dentistry, PaeCoMeDiSGhent UniversityGhentBelgium
  6. 6.Department of Dentistry—Community Dentistry and Oral Public Health, PaeCoMeDiSGhent UniversityGhentBelgium
  7. 7.IbiTech-Medisip-Infinity labGhent UniversityGhentBelgium
  8. 8.MOLECUBES NVGhentBelgium
  9. 9.Department of Oral and Maxillofacial SurgeryGeneral Hospital Saint-LucasGhentBelgium

Personalised recommendations