The Role of Bone Alkaline Phosphatase and Osteocalcin in Saliva as Indicators of Skeletal Maturity in Children

The aim of this study was to investigate the levels of bone alkaline phosphatase (BALP) and osteocalcin (OC) in the saliva of growing patients of different maturation levels. The sample consisted of 55 patients (34 females and 21 males of 7-16 years old). Two milliliters of saliva were collected and BALP and OC levels were assessed. Skeletal age was estimated using the cervical vertebral maturation method (CVM). The relationship between the biomarkers' concentration in saliva and skeletal age was examined with the Spearman's coefficient "rho" (rho). Correlations between skeletal age groups and BALP and OC concentrations were assessed with the Kruskal-Wallis or the Mann-Whitney tests. No statistically significant differences in the levels of BALP (p = 0.568) and OC (p = 0.996) in saliva were identified according to the patient's skeletal age. The use of BALP and OC levels in saliva seems to be dubious for skeletal growth assessment. However, slightly differentiated levels of those biomarkers, especially of BALP, through the different maturation stages, with higher concentrations at the pubertal phase, have been noticed. More studies are needed to clarify the exact potential role of these biomarkers as predictors of pubertal onset.