Digital radiography and GIMP software in mandibular sex estimation: implications for forensic anthropology

Abstract

Background: Forensic anthropology frequently utilizes mandibular features to establish biological sex. The mandible, being the most resilient cranial bone, demonstrates marked sexual dimorphism. Among its indices, the gonial and antegonial angles have emerged as reliable parameters for sex differentiation. With digital imaging widely available, open-source tools such as GIMP allow precise, reproducible, and cost-effective morphometric analysis of orthopantomograms (OPGs).

Materials and Methods: This cross-sectional study analyzed 500 archived OPGs (250 males, 250 females; age 20–40 years) from AIIMS Nagpur. In orthopantogram, gonial and antegonial angles were measured bilaterally using GIMP (v2.10.34). Statistical analyses were conducted with Jamovi (v2.6).

Results: Females exhibited significantly larger gonial (130.80° ± 5.35) and antegonial (167.85° ± 2.15) angles compared to males (123.03° ± 5.43 and 162.69° ± 2.12, respectively; p < 0.001). Regression analysis confirmed significant dimorphism, even after adjusting for age. Discriminant function analysis demonstrated that both angles contributed positively to sex classification, yielding a robust predictive model. No significant sex-related differences were observed in age group distribution (χ² = 0.812, df = 2, p = 0.666).

Conclusion: Mandibular gonial and antegonial angles measured from OPGs using GIMP demonstrate significant sexual dimorphism in the 20–40-year age group. Females consistently displayed larger angular values, supporting their diagnostic value for sex estimation. These findings underscore the relevance of digital radiography and open-source analysis in forensic anthropology, orthodontics, and maxillofacial surgery.

Keywords: Forensic Anthropology, Mandible,  Sexual Dimorphism,  Gonial Angle,  Antegonial Angle, Orthopantomogram,  GIMP Software