Facial approximation: an evaluation of mouth-width determination

Area of Science:

• Forensic Anthropology
• Facial Reconstruction
• Craniometry

Background:

• Facial approximation relies on predicting soft tissue dimensions from skeletal remains.
• Existing methods for estimating mouth width from skulls lack rigorous scientific validation.
• Inaccurate soft tissue predictions can compromise the reliability of facial approximations.

Purpose of the Study:

• To evaluate the accuracy of commonly used methods for determining mouth width from skull morphology.
• To compare the efficacy of established methods against a newly proposed guideline.
• To assess the impact of inaccurate mouth width predictions on facial approximation reliability.

Main Methods:

• Photogrammetric analysis was employed on living Australian European and Central/South East Asian participants.
• Three established methods were tested: pupil distance, medial iris border distance, and canine-premolar junction distance.
• A novel guideline was developed and tested, correlating canine width with pupil distance.

Main Results:

• Established methods 1 (pupil distance) and 3 (canine-premolar) showed significant inaccuracies, overestimating and underestimating mouth width, respectively.
• Method 2 (medial iris borders) was more accurate but still underestimated mouth width.
• The new guideline demonstrated no statistically significant difference from actual mouth widths, with minimal average deviation.

Conclusions:

• Commonly used methods for mouth width estimation in facial approximation are unreliable.
• The newly proposed guideline offers a more accurate approach for predicting mouth width from skeletal remains.
• Further validation of the new guideline with independent datasets is recommended to enhance forensic facial reconstruction accuracy.