Magnetic resonance imaging of third molars: developing a protocol suitable for forensic age estimation

Area of Science:

• Forensic Anthropology
• Radiology
• Dental Science

Background:

• Traditional dental age estimation relies on radiographs of third molar development, exposing individuals to ionizing radiation.
• Magnetic resonance imaging (MRI) presents a radiation-free alternative for visualizing dental development in three dimensions.

Purpose of the Study:

• To develop a magnetic resonance imaging (MRI) protocol for visualizing all third molars.
• To specifically focus on assessing third molar root apex development for forensic age estimation.

Main Methods:

• Evaluated various MRI sequences (T1 vs T2 weighting, UTE, fat suppression) and parameters (resolution, slice thickness, 3D imaging).
• Utilized ex vivo porcine jaws and in vivo scans of 10 volunteers (aged 17-25).
• Assessed image suitability based on resolution, contrast, signal-to-noise ratio, and acquisition time.

Main Results:

• T2-weighted images were superior to T1-weighted images for visualizing root apices.
• An in-plane resolution of 0.33 x 0.33 mm² was necessary for clear visualization of root apices.
• A T2 FSE sequence with a 2 mm slice thickness achieved sufficient resolution and contrast within acceptable acquisition times.

Conclusions:

• Three Tesla MRI is a viable technique for forensic age estimation of third molars.
• A T2 FSE sequence offers the required resolution for age assessment within a clinically acceptable timeframe.