GEOMETRIC MORPHOMETRIC STUDY OF MANDIBULAR BODY MORPHOLOGY IN CHILDREN: IMPLICATIONS FOR FORENSIC AGE AND SEX ESTIMATION

The mandible is one of the bones that have special characteristics in comparison to other bones. The mandible is the strongest bone on the face and an important part of the forensic profile. The purpose of this study was to identify differences in the morphology of the mandible body related to age and sex in children used on the panoramic radiograph. Eight anatomical landmarks were digitised on 305 panoramic radiographs (159 male and 146 female) using TPSdig2 software. The shape data were analysed with MorphoJ using Generalised Procrustes Analysis (GPA), Principal Component Analysis (PCA), Canonical Variate Analysis (CVA), and Discriminant Function Analysis (DFA). The shape and size differences were tested by Procrustes ANOVA. Two groups (G1 male and G2 female) were used for the determination of sex, while three age groups (3 to 6, 7 to 9 and 10 to 12 years) were tested for age prediction. Morphological variation was visualised with wireframe and lollipop diagrams. The total shape variation was explained by the first four principal components (PC1–PC4) covering 82%. DFA accuracy to classify sex was 64.15% (G1) and 67.12% (G2), and of cross validation was 61.63%, and 63.69%. Inequalities based on age group were generally more accurate: 81 to 87% (Age Group 1) and even up to 93.68% for the older subgroups. Procrustes ANOVA revealed no difference in centroid size for the sexes, but significant differences in shape (p < 0.001). Shape and size variations were both significant between age groups (p < 0.001). Geometric morphometric techniques can demonstrate discriminatory features in mandibular body shape for age and sex. It's a useful screening tool for forensics in cases involving children.

Mandibula merupakan salah satu tulang yang mempunyai ciri khas berbanding tulang lain. Ia adalah tulang paling kuat pada bahagian wajah dan memainkan peranan penting dalam profil forensik. Kajian ini bertujuan mengenal pasti perbezaan morfologi badan mandibula yang berkaitan dengan umur dan jantina dalam kalangan kanak-kanak melalui radiograf panoramik. Sebanyak lapan titik anatomi telah didigitalkan pada 305 radiograf panoramik (159 lelaki dan 146 perempuan) menggunakan perisian TPSdig2. Data bentuk dianalisis melalui MorphoJ menggunakan Analisis Prokrustes Teragih (GPA), Analisis Komponen Utama (PCA), Analisis Variat Kanonikal (CVA), dan Analisis Fungsi Diskriminan (DFA). Perbezaan bentuk dan saiz diuji menggunakan Procrustes ANOVA. Dua kumpulan (G1 lelaki dan G2 perempuan) digunakan untuk penentuan jantina, manakala tiga kumpulan umur (3–6, 7–9 dan 10–12 tahun) diuji untuk ramalan umur. Variasi morfologi divisualisasikan melalui rajah wayar (wireframe) dan lollipop. Jumlah variasi bentuk dijelaskan oleh empat komponen utama pertama (PC1–PC4) meliputi 82%. Ketepatan DFA dalam mengklasifikasikan jantina ialah 64.15% (G1) dan 67.12% (G2), manakala ketepatan pengesahan silang ialah 61.64% dan 63.70%. Bagi kumpulan umur, ketepatan klasifikasi adalah antara 80.17% hingga 93.68%. Procrustes ANOVA mendapati tiada perbezaan saiz centroid antara jantina, namun terdapat perbezaan signifikan dalam bentuk (p < 0.001). Variasi bentuk juga signifikan antara kumpulan umur (p < 0.001). Teknik morfometrik geometri berupaya menunjukkan ciri diskriminatif dalam bentuk badan mandibula bagi tujuan anggaran umur dan jantina. Ia merupakan alat saringan yang berguna dalam bidang forensik melibatkan kes kanak-kanak.