Identification of bone-specific alkaline phosphatase in saliva and its correlation with skeletal age

Context: Bone-specific alkaline phosphatase (B-ALP), a product of osteoblasts, is a bone formation marker whose serum levels fluctuate with puberty and adolescence. Aims: This study aims to assess B-ALP levels in saliva and correlate it with different skeletal maturity stages of hand-wrist radiographs using Hagg and Taranger method. Settings and Design: Observational study and cross-sectional design. Subjects and Methods: Total sample comprised of 90 individuals, right hand-wrist radiographs, and 2 ml unstimulated whole saliva samples taken from each patient on the same day. The hand-wrist radiographs were traced and staged into 5 subgroups (18 individuals each) according to Hagg and Taranger method. Statistical Analysis Used: One-way analysis of variance (ANOVA) and Tukey's multiple post hoc test. Results: The comparison of salivary B-ALP values between the different skeletal subgroups using one-way ANOVA depicted statistically significant results (P = 0.0003). Pairwise comparison using Tukey's multiple post hoc procedures showed that salivary B-ALP levels were comparatively higher in subgroup 3 and that the difference between subgroups 1 and 3 (P = 0.0109) and subgroups 3 and 5 (P = 0.0014) was statistically significant. Conclusion: B-ALP could be successfully identified and quantitatively estimated in saliva and showed significant correlation with different skeletal age subgroups as determined by Hagg and Taranger method.