• Phonkit Sinpitaksakul, D.D.S., Grad. Dip. Clin.
• Sunpatch Benjavongkulchai, D.D.S., M.Sc.
• Anansit Jinawong, D.D.S.
• Chawanat Wongpattaraworrakul, D.D.S.
• Sirapat Pipattanachat, D.D.S.
• Pisha Pittayapat, D.D.S., M.Sc., Ph.D.*

Objective: The aim of this study was to evaluate developmental stages of the radius bone and
compare it with the chronological age of Thai population.

Methods: Three hundred hand and wrist radiographs (150 males, 150 females) of subjects (age 7-20
years) were retrospectively collected. The developmental stages of the distal end of the radius bone
were modified from Tanner-Whitehouse 3 and categorized into 4 stages: 1) non-capping, 2) capping,
3) partial fusion and 4) complete fusion. Each radiograph was scored by 3 observers. Sixty subjects
were re-evaluated for intra- and inter-observer agreement. Statistical analysis was performed.

Results: The mean ages of each stage were presented: stage 1, 10.63 ± 1.52 years in males and
9.54 ± 1.08 years in females; stage 2, 13.83 ± 1.15 years in males and 12.06 ± 1.28 years in females;
stage 3, 15.39 ± 0.74 years in males and 14.18 ± 1.22 years in females; stage 4, 17.57 ± 1.45 years in
males and 17.04 ± 1.56 in females. Statistically significant differences were found between ages of
males and females in stage 1, 2 and 3. Distribution of data showed that all subjects with partially
fused radius bone were younger than 18. However, subjects presented with completely fused radius
bone could be at least 15 years old. Additionally, when the subjectûs known age was 18 years old or
older, complete fusion of the radius bone could be observed.

Conclusion: Radius bone developmental staging is a potential predictor for age estimation of legal
cases in Thai population. Further studies with increased number of subjects will be of benefit.

(CU Dent J. 2018;41:13-22)